List of presentations

Hydrologic connectivity as a design element promotes plant diversity and functional soil development in created wetlands in Virginia, USA
Ahn C.A., Dee S.D., Peralta R.P., Wolf K.W.

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Wetland mitigation banks have recently been a popular way of compensating natural wetland loss in the U. S. However, created mitigation wetlands do not always adequately develop and/or provide ecological functions lost with the loss of natural wetlands. In most cases of wetland mitigation, some measure of vegetation is a performance standard, and in many cases, vegetation is the only performance standard in the post-creation monitoring. We are currently monitoring ecosystem development in three wetland mitigation banks, all created in the Virginia piedmont with varying design elements. The purpose of the study is to investigate structural and functional attributes of vegetation and soils that are in development in created wetlands as affected by hydrologic connectivity as a design element. We conducted floristic assessments for herbaceous vegetation in a few created wetlands, using Floristic Quality Index (FQI), and measured plant biomass production as peak biomass, both for above- and below-ground. We also measured several soil physicochemical parameters (i.e., pH, bulk density, organic matter content, total carbon and total nitrogen content), and fingerprinted soil bacterial communities using both universal primer and a functional primer for denitrifying community in the wetlands. The preliminary results show a clear clustering among sites by their age for vegetation, soil physicochemistry and bacterial community, and some patterns within the sites by soil moisture affected by the design element. All of the vegetative attributes, including FQI, were fairly influenced by site hydrologic regime with significantly higher values of percent cover, H’, FQI observed in relatively drier sites. The soil parameters seemed associated with age and hydrologic connectivity, but the association varied by site. Soil microbial community profiles showed a clear clustering between the sites (i.e., by age), and within the sites mostly by hydrologic regime. Investigating the possible relationships between the variables studied may deliver useful information in developing indicators that can be used in evaluating wetland ecosystem quality.
Keywords: wetland creation, plant diversity, soil physicochemistry, soil bacterial community

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Environmental factors associated with long-term changes in chlorophyll-a concentration in the Amazon floodplain
Alcântara E.H., Novo E.M.L.M., Stech J.L., Barbosa C.C.F., Bonnet M.P.

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The study of chlorophyll-a concentration in flood pulsed wetlands has been based mostly on datasets obtained at different sites or along track lines occupied during cruises. In situ water data, however, are limited in time and space. This is a particularly serious constraint in remote regions of difficult access, such as the Brazilian Amazon floodplain waters. Moreover, in situ sampling monitoring has a high probability of undersampling. Some authors have used satellite imagery to address the wide range of spatial and temporal variability of chlorophyll-a concentration in the Brazilian Amazon floodplain. However, these authors have estimated the chlorophyll concentration in a synoptic manner. Also, the authors don’t discuss the relationship between the chlorophyll concentration and other environmental parameters that might explain the reported variability in time and space. Long-term environmental time series of continuously collected data are fundamental to identify and classify pulses, and in determining their role in aquatic systems. Based on this, this paper has the objective of analyzing the chlorophyll-a concentration time series and its relationship with other environmental parameters. It uses in situ daily mean limnological (chlorophyll-a concentration, water level, water surface temperature, pH and turbidity) and meteorological (wind intensity, relative humidity and short wave radiation) data collected through an automatic system (Integrated System for Environmental Monitoring-SIMA). SIMA is a set of hardware and software designed for data acquisition and real time monitoring of hydrological systems. The data are collected in pre-programmed time intervals (1 hour) and are transmitted by satellite in quasi-real time for any user in a range of 2500 km from the acquisition point. We used Pearson correlation to determine the quantitative relation between the chlorophyll time series and other environmental parameters. The periods of high variability were studied using the Fourier power spectrum and the time-frequency structure of chlorophyll time series were analyzed using the wavelet power spectrum. To show the relationship between chlorophyll and the significant time series highlighted by Pearson’s correlation the cross wavelet analysis was carried out and the coherence and phase analyzed. The time series of chlorophyll-a shows two high peaks (47 µg/L and 53.30 µg/L) of concentration during a year: first during the rising water and second during the low water level. A little peak was observed during the high water level (10 µg/L). For the most part of rising, high and falling water level, the chlorophyll concentration is often low (from 2.26 µg/L to 9.11 µg/L). The causes of this were discussed. The relationship between the chlorophyll-a time series and others parameters were analyzed using the Cross Wavelet and coherence and phase concepts. With periodicities ranging from 2-60 days the chlorophyll-a concentration well agrees with turbidity and water level; and coherence ~1 and in-phase for rising and low water period.
Keywords: Time series, wavelet, Fourier, Cross-wavelet, limnology, Amazon floodplains, chlorophyll

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The Mesopotamia Marshlands National Park Planning Process
Alwash A., Cattarossi A., Galli G., Fant M.

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One of several Projects implemented by Nature Iraq is the establishment of a National Park in the Marshlands areas as a means to bring economic development to the region in a sustainable way that improves and protects the environment and cultural heritage. The selected site for the park (Central and Abu Zirig Marsh) was determined through a step by step process conducted with the relevant Iraqi Ministries. The primary objective of the Mesopotamian Marshland National Park is to provide the southern marshes of Iraq with a plan to guarantee the restoration/protection of the environment and the cultural heritage while ensuring a sustainable development of the territory, by encouraging diverse economic activities that integrate well with the Park, and increasing the values of its unique features. But a key objective of such a park is the eventual development of sustainable tourism. The strategy for the establishment and management of the Park foresees three parallel development paths (Scenario 1 Education/research; Scenario 2 Socio-economic development; Scenario 3 Tourism) to be followed. The three scenarios are built on a common cross-cutting “basis” which is the Conservation of Nature (Scenario 0). A draft management plan of the park was presented in April 2008 to the Iraqi authorities. The document’s proposals have then been shared with the local population through a consultation process led by a specially appointed committee. Aiming at demonstrating and enforcing the message of sustainability to the inhabitants of the park’s neighboring areas, several pilot projects (environmental awareness raising, aquaculture, water buffalos, drip irrigation for date palms orchards etc.) are being implemented with the active cooperation of the local committee. The results of these activities will be used to define the final version of the management plan, which provides the guidelines for the establishment and development of the National Park.
Keywords: Iraq, Mesopotamian Marshlands, Protected Areas, Sustainable Development, Eco Tourism, Environmental Education, Environmental Legislation, Stakeholder Involvement, Biodiversity

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A Spatially Explicit Carbon Cycling Model to Test Floodpulse Concepts in the Upper Mississippi River
Amato K.R., Martin B., Pope A., Hannon B., Theiling C., Ickes B., Houser J., Sparks R.

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Principal tenets of the Floodpulse Concept (FPC), published in 1989, are: (1) the annual flood cycle is the major driving variable that determines patterns of productivity; and (2) most of the production in the river-floodplain ecosystem is derived from the floodplain. The FPC noted that annual productivity in temperate zone rivers is likely to vary according to the coupling of the floodpulse with the annual temperature regime. Tenets of the FPC and alternative concepts have been tested using stable isotope techniques to determine the origins of organic matter in higher level consumers (e.g., fish). One difficulty with short-term studies, including the isotope studies, is seasonal and year-to-year variability in temperature-flood coupling and in the extent and timing of connection between river channels and their off-channel areas, including the floodplains. Short-term studies provide “snapshots” of flood-pulsed systems, but may not represent the patterns that prevail over time spans of decades. Spatially explicit models that can map stocks and flows of carbon in response to water, sediment and temperature regimes would be useful in testing theory, guiding sampling design, and in assessing impacts of projects, such as dams and diversions that change water regimes. We describe a spatially-explicit carbon model which has been coupled to a spatially-explicit hydraulic model to predict patterns of productivity in floodplain-river ecosystems. The ecological model was developed using freeware Net Logo 4.0.4 and was based on maps of water depth and velocity generated by an ADH 2-dimensional hydraulic model. Any 2-D hydraulic output in map format could be used by the ecological model. Hydraulic models are usually developed during planning and design stages for dams and diversions and can be used by the ecological model to assess impacts of the projects on trophic dynamics. ADH refers to ADaptive Hydraulics, a multi-dimensional hydraulic modeling program in development by the U.S. Army Corps of Engineers. Aquatic areas on the maps varied with river stage and were divided into 30 m2 patches. Fluxes of carbon into and out of the patches were based on the 2-d hydraulic model. The time step was one hour. Transfers of carbon among stocks within a patch were based on physical processes of scour and settling and biological processes of photosynthesis, respiration, predation, excretion, egestion, natural mortality, and decomposition. Carbon stocks included: particulate organic carbon (POC), detritus (POC that is in or on the sediment), dissolved organic carbon (DOC), decomposers, phytoplankton, aquatic macrophytes, periphyton, herbivores, and consumers (of herbivores, detritus, decomposers, or other consumers). Primary productivity responded to temperature, light, and water velocity. There were space limitations and prey refuges (i.e., prey cannot be reduced to zero). The model was developed for a reach of the Upper Mississippi River (UMR), but is applicable to other river systems. Key rate coefficients were based on literature or data from the UMR. Different ecological parameters and hydraulic maps could be developed to answer different questions or to tailor the model to other reaches or rivers.
Keywords: Flood Pulse Concept, carbon cycling, spatial modelling, Mississippi River

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The long, slow pulse: adaptation law and policy for pulsing wetlands
Ankersen T.T.

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Water bodies and wetlands pulse over variable temporal cycles, some of which can be decadal. Moreover, in some cases, the cycles are episodic and/or stochastic in nature. Tropical cyclones provide a good example of this sort of episodic stochasticity. In others cases, episodic pulsation can occur slowly and relatively predictably over time, as in the case with certain lakes in the North Central Region of the United States and in the karst region of northern Guatemala. These sorts of known and unknown pulsing cycles challenge human instinct, as presented by development patterns that reflect human desire to live on or near the water. Humans have not adapted their development planning to account for wetland pulsing, resulting in adaptation responses that favor structural solutions to remove or displace pulsing in areas of human habitation. More recently, a new challenge has emerged to test human development planning in the coastal zone. Anthropogenically induced climate change is expected to cause mean sea level to rise in a range of at least 7 to 23 inches over the rest of this century. This does not account for forces that could accelerate the rate and rise of sea level through ice melt. The temporal effect of gradual sea level rise is a “long, slow pulse.” If they are to be maintained coastal wetlands will have to be permitted to migrate. Humans may be in the way. Planners and some policy makers have begun to take sea level rise seriously. This has resulted in the development of an emerging body of national and sub-national climate change policy. Climate change policy addressing sea level rise typically contemplates three strategic approaches to human settlement: protection (shoreline hardening), accommodation (flood-proofing) and strategic retreat. These approaches are not mutually exclusive and can be considered in concert through region scale planning. This planning approach can also be applied to the maintenance and restoration of pulsing inland wetlands. This paper will review regulatory and incentive-based policy tools being discussed in terms of planning for sea level rise, and consider their application to pulsing inland wetlands and water bodies. Institutional and legal barriers to the implementation of these tools will be discussed. Examples where these tools are currently being applied will also be presented.
Keywords: Adaptation, law, policy planning, strategic retreat, flood-proofing, protection, climate change, sea level rise

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Integrated management of the Makgadikgadi Wetlands to enhance development, livelihoods and biodiversity conservation.
Arntzen J.W., Ruthenberg P.

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Southern African non-perennial rivers: Proposing a new prototype methodology for assessing environmental water requirements
Avenant M., Seaman M.T., Armour J., Barker C.H., Du Preez P.J., Hughes D., King J.M., Rossouw L., Van Tonder G., Watson M.

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Ecological consequences of diurnal flooding in tidal freshwater wetlands
Barendregt A., Wassen M.

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Diurnal flooding can be observed in the upper end of tidal estuaries, where flooding water originating from the river is constantly fresh. Here, the input from the river is confronted with a tidal wave, so that the sand banks, mud flats, low and high marshes and tidal forests are flooded mostly twice a day. A sequence of processes is linked to these flooding conditions. First, the physical processes organize new locations with sedimentation where succession can start, or they start sedimentation or erosion in existing types of vegetation. Second, the mixing of river water with the estuarine water starts chemical processes with cycling of nutrients and metals and the precipitation of suspended matter. Balance studies with water flowing in and out of a wetland indicate that within a few hours the nitrification and denitrification is high (10-60 %). Most phosphorus is fixed in the soil by iron. Silica is recycled to a structure that is bio-available. Third, the ecological conditions indicate that biomass production is extremely high because nutrients and water are not limiting. The two most important factors that explain the variation in the vegetation are the elevation, with the ecological consequence of the flooding frequency and period, and the succession with the accumulation of organic matter in and on the soil. Next to this, the vegetation might develop into woodland, or remain as a marsh, also depending on the human impact. The animals in tidal freshwater wetlands live in a range from aquatic to terrestrial habitats. The flooding frequency is a determining factor in (semi)terrestrial animal distribution comparable with the vegetation. At least three guilds are given in the flooding frequency: the aquatic, the humid terrestrial and the intermediate animals; the latter characteristic for shorelines. The fish fauna is complex, since there are groups from estuarine - even from saline - conditions, from riverine conditions, and anadromous species that use these wetlands in their migration or use the tidal wetlands to mature. Such wetlands are used by society for all kind of purposes. Many areas are reclaimed for agriculture, housing and to create harbours; cities like Hamburg, Antwerp, Philadelphia and Washington DC are created in between wetlands of this type. Restoration projects are applied at many locations, for the profits for men and nature. The most severe threat in future is the seawater rise, because these wetlands are the first that will be flooded or changed by inflow of saline water.
Keywords: tidal freshwater wetlands, diurnal flooding

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Economic value of the Okavango Delta, Botswana, and implications for management of water and wildlife
Barnes J.I., Turpie J.K., Arntzen J., Lange G.-M.

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The economic value of the Okavango Delta, Botswana, was estimated based on existing information and key informant interviews, in order to evaluate its importance and the broad implications of future management options. Households in and around the delta earn a total of P225 million per year from natural resource use, sales, salaries and wages in the tourism industry, and rents and royalties in CBNRM arrangements (1US$ = Pula 5.4). Its wildlife supports a thriving ecotourism industry which was estimated to generate a gross income of some P1 115 million. Groundwater recharge is worth an estimated P16 million, carbon sequestration P86 million and wastewater treatment about P2.2 million. The provision of a refuge for certain wildlife species that migrate to other area is worth some P30 million. The total impact of the direct use of the resources of the Delta is estimated to be P0.96 million. Thus the wetland contributes 2.1% of the country’s GNP. The natural capital asset value of the Okavango Delta is some P3.4 billion. Management of the Okavango Delta and the Ramsar Site in general will need to strike a balance between meeting the needs of the people living in and around the delta and generating its important contribution to the national economy. People living in the study area derive roughly equal benefits from natural resources and from tourism, the latter being slightly higher. However, there is an important difference in the form that these benefits take. Natural resources provide subsistence value and some cash income. They have the capacity to provide a safety-net for households that suffer shocks and provide a risk-spreading mechanism for poor households that are vulnerable to the vagaries of environmental variability. Tourism, on the other hand, generates hard, reliable cash income to households, providing the type of income that most households aspire to. Thus both aspects are important. Tourism also makes a substantial contribution to Botswana’s GNP, which in turn provides more revenue and social security to households all over the country. The implications of the potential future changes in freshwater inflow into the delta due to extraction and climate change, as well as the implications of potential changes in land use management of the delta were evaluated through scenario analysis and found to be significant. It is essential that Botswana works to ensure adequate flows in future through international agreements and maintains a strong conservation focus in the delta.
Keywords: Key words: wetland valuation, ecosystem services, environmental accounting, environmental management, environmental flows

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Impact of flow changes on livelihoods and national income in the Okavango River Basin
Barnes J., Saraiva R., Mmopelwa G., Mbaiwa J., Magole L., Wamunyima D.

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This paper reports on the socio-economic assessment carried out for the transboundary diagnostic assessment (TDA) of the Okavango River Basin. It formed part of an environmental flows assessment (EFA) which included hydrological, biophysical and socio-economic elements, and which measured the likely impacts of water use developments on flows and flow-related natural resources, livelihoods and incomes. Empirically based natural resource use models were used to value all livelihoods and income generated from river/wetland-related natural resources use in the basin. These data were combined with the EFA model to measure the likely effects of flow change on these values. The Okavango river basin is thus far relatively unaffected by development. Human populations in the basin tend to be poor and rely significantly on natural resources for their livelihoods. River/wetland-based natural resources contribute significant proportions of the household income of basin residents (19% in Angola, 32% in Namibia and 45% in Botswana). They contribute US$60 million annually to livelihoods in the basin as a whole (US$4.4 million in Angola, US$12 million in Namibia, and US$44 million in Botswana). Their direct contribution to national incomes amounts to US$100 million annually, and their total economic impact amounts to some US$234 million annually. These values are derived mostly through tourism in the lower parts of the basin, but households also directly benefit from fish, reeds, wetland grass, wetland grazing and wetland crops. Future water use developments, in the upper parts of the basin, will significantly reduce these flow-related incomes. Major development of water uses might cause long term economic losses amounting to US$65 million in Angola, US$330 million in Namibia, and US$2.1 billion in Botswana. Such water use development might reduce average household livelihoods income by 9% in Angola, 13% in Namibia, and 32% in Botswana. Planning for future development in the basin needs to take these findings into account. Macro-economic cost-benefit analysis should be applied to ensure that basin development minimises such losses and contributes optimally to national welfare.
Keywords: Key words: Livelihoods, Economic contribution, Flow-related change, Impacts

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Environmental flows and wetland restoration in the Lower Zambezi River basin: progress and prospects
Beilfuss R., Chiburre J., Bento C., Guele R.

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The Lower Zambezi basin supports nearly 4 million people and features the Zambezi Delta, Mozambique’s premier Wetland of International Importance under the Ramsar Convention. Over the past century, hydropower and infrastructure projects have substantially altered hydrological patterns and processes in the lower Zambezi basin and delta, reducing ecosystem services, rural livelihoods, and biodiversity in the system. A new partnership between Mozambique water management authorities, dam operators, development planning authorities, research institutions, and conservation NGOs was established to assess the opportunities and constraints for implementing environmental flow releases (EFRs) to restore the ecological health of the river basin and key wetlands. A preliminary environmental flow process, building on more than a decade of bio-physical and socio-economic research, was undertaken to identify potential conflicts/tradeoffs among water users/water use concerns in the Zambezi Delta with respect to EFRs (flood-related small-scale agriculture, commercial large-scale agriculture, estuarine ecology, coastal fisheries, freshwater fisheries, livestock, large mammals, waterbirds, floodplain vegetation, invasive vegetation, natural resource utilization, water quality, groundwater recharge/water supply, in-channel navigation, settlement patterns, human health) and to explore the potential for improving delta conditions through EFRs from Cahora Bassa Dam. The low capacity to inflow ratio (0.67) for Cahora Bassa (mean annual inflows ~77.1 Bcm and live storage capacity at normal maximum operating level is 51.7 Bcm) forces late dry season water spillage most years to protect the dam wall, according to a design flood rule curve. Simulation modeling to assess hydrological feasibility of EFRs indicates that immediate improvement in the delta flow regime could be made with almost no impact on hydropower production by redistributing those outflows to generate early wet season EFRs that also provide improved storage capacity to attenuate large, potentially damaging floods (especially when downstream tributaries are in peak discharge). For example, a 2-week discharge of 4500 cms in December could be achieved in 95.6% of all years with 97.3% firm power reliability and 99.6% of baseline energy production, and a 4-week discharge of this magnitude and timing could be achieved with 96.7% firm power commitment and 99.2% of baseline energy production. Ongoing steps in the operator-driven process aim to (1) engage stakeholders in consensus-building for EFRs through information exchange and stakeholder education; (2) define measurable objectives and indicators and prepare initial EFR recommendations in a workshop setting; (3) implement an effective flood forecasting and warning system for the reservoir and downstream tributaries; (4) establish a robust monitoring and data collection program (hydrological, biophysical, socio-economic); (5) make water release experiments; (6) monitor and evaluate releases for adaptive management; (7) define new EFRs as appropriate in follow-up workshops. EFRs are being closely linked to integrated river basin development planning and protected area management.
Keywords: land use, flood pulse, flood protection, consensus-building, monitoring, adaptive management

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How flooding, competition and grazing influence Phyla canescens invasion into floodplain wetlands, Australia
Berney P.J., Price J.N., Ryder D.S., Whalley R.D.B., Wilson G.G., Gross C.L.

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The disturbance provided by seasonal flood pulses is recognised as a major factor shaping wetland plant community composition. Changes to such an historical disturbance regime in wetland systems can facilitate the invasion of exotic species. However, attempts to revert to a more 'natural' disturbance regime may not necessarily restore native dominance as this will depend upon the competitive interactions with invading species, and other agents of disturbance such as livestock grazing. Indeed, the success of attempts to reinstate an historical disturbance regime will be governed by whether the change causes mortality of the invaders or if the vigour of the native species is increased enabling them to out-compete the invaders. On numerous inland terminal floodplain wetlands in semi-arid regions of Australia's Murray-Darling Basin, water couch (Paspalum distichum) meadows are important feeding areas for colonial nesting waterbirds and are also highly valued for cattle grazing. However, these meadows are being transformed as water couch is being replaced by the alien species lippia (Phyla canescens), an invasive perennial forb from South America. In recent decades, water resources development for irrigated agriculture has substantially altered the water regime into these wetlands. Altered hydrological conditions are believed to have enhanced the competitive ability of lippia with respect to native species, facilitating its establishment in core wetland areas. In addition, grazing pressure from domestic livestock and native herbivores may be interacting to create conditions favouring establishment of lippia. This study investigated the competitive interactions between water couch and lippia under a range of water levels in both the field and glasshouse conditions to determine the influence of water regime on shaping plant community composition. In addition, GPS trackers on cattle were used to monitor patterns in grazing behaviour. In the field, an abrupt boundary was observed between zones dominated by water couch and those dominated by lippia, separated by a narrow ecotone of approximately 8m in which both species appeared to co-exist. Following flooding, the percent foliar cover of water couch in the ecotone increased but had returned to near pre-flood levels within 12 weeks post-flooding. GPS collar data from cattle showed a high level of grazing pressure on water couch communities. Following the field study, a factorial competition experiment using four inundation levels and six combinations of intra-and inter-specific competition was set up in a glasshouse. The results indicated that the while competitive ability of lippia is reduced with flooding, inundation does not actually cause mortality, while morphological changes in the lippia plant when inundated may assist its dispersal. Both water couch and lippia had similar competitive effects on each other across all water levels. These results indicate that it is unlikely that changes to the water regime that increase the period of flooding will eliminate lippia from these wetlands. Managers may need to reassess the effects of grazing pressure as it is evident that grazing levels are more uneven among wetland plant communities than previously thought.
Keywords: Competition, Grazing, Disturbance, Paspalum distichum, Phyla canescens

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The effect of flow regulation in the Orange River on the river estuary
Biggs D.

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The Orange River is the most southerly large international river in Africa. The river basin is shared by Botswana, Lesotho Namibia and South Africa. Due to the fact that most of the basin is in an arid area with a long dry season, while extensive flooding occurs in the summer rainy season, the river has been extensively regulated, particularly in South Africa which is the most economically active country in the region. Both the diamond and gold fields of South Africa and Lesotho lie in the Orange River Basin. Water from the river is used not only for agriculture, but mining, industry, hydropower generation and human consumption as well. This development has a significant influence on the Orange River Mouth, which is a Ramsar Conservation Site. The source of the Orange River is in the mountains of Lesotho on the eastern side of Southern Africa which forms the watershed. Half the runoff of the river originates there. Winter precipitation is in the form of snow, which melts in September causing a freshet , or sudden stream flow. The rest of the river basin is in a summer rainfall area, causing the river under natural conditions to sometimes stop flowing in the late winter months. Widespread thunder storms in summer cause at least high river flows, often resulting in flooding. Due to regulation of the river via large dams in the middle reaches of the river which are used both for hydropower generation as well as irrigation, inter-basin transfers, mining, industry and human consumption, the flow regime of the river is not only altered in time, but in volume as well.The Orange River discharges into the Atlantic Ocean on the border between Namibia and South Africa. Due to the diamondiferous terrain traversed by the river, large alluvial diamond deposits are found at the mouth of the river. These are mined both in Namibia and South Africa. Sandwiched between these two mining developments is the Orange River Mouth which is a Ramsar site. The ecosystem relies on the intermittent dry spells and flood pulses of the Orange River for survival. The River mouth closes during dry spells, allowing a salt marsh to form. During high flow periods, the sand bar across the river mouth is breached, flushing the estuary. This has given rise to a unique environmental scenario. Due to the regulation of the river as well as the mining activities on both sides of the river mouth, this hydrological pattern has been changed significantly, severely compromising the ecology of the river mouth. This paper looks at the magnitude of the influences of the activities mentioned above as well as the significance thereof, and discusses alternative mitigating measures to simulate the natural conditions in an attempt to stem the degradation of the Ramsar Site.
Keywords: flow regulation, Orange River

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Implications of Irrigation Farming on an Ephemeral River System: The Case of the Hardap Irrigation Scheme, Namibia
Biggs D.

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Hardap Irrigation Scheme is located in the Fish River, southern Namibia. The Fish is an ephemeral tributary of the Orange River.. The Hardap Irrigation Scheme was built in the 1960s and consists of Hardap Dam, with a capacity of 300 million m³ and an irrigation scheme of 2,200 ha downstream of the dam. At the time that the scheme was constructed, it was not customary to do environmental impact assessments as it is today. For that reason it is of interest to evaluate the environmental and social impacts of this scheme on the approximately 100-km reach of the river directly affected by the dam. Due to the variance in flow, (or pulsing), typical of an ephemeral river, the design capacity of the dam was radically influenced. In order to achieve a realistic assurance of supply for the irrigation scheme, the capacity of the dam is three times the mean annual runoff (MAR). In spite of its large capacity in relationship to the runoff, the assured yield of the dam is only about half of the MAR. Another result of the varying size of flood pulses, is that floods still occur downstream of the dam. The first major flood was in 1971, shortly after the dam was completed. Major floods still occur, doing damage to both the irrigation scheme as well as the town of Mariental. The soils chosen for irrigation were highly saline due to the high evaporation rate which is prevalent in such an arid area. For that reason the irrigation scheme was designed for flood irrigation to enable flushing out of salts from the irrigation fields. In spite of the land having been under irrigation for more than 40 years, flood irrigation is still widely practised. The preferred crops of the majority of farmers are cereals, alternating wheat in winter with maize in summer, thus leading to a harvest of two crops a year. Since most of the farmers still practise flood irrigation, return flows to the river are high, as flood irrigation is one of the most inefficient forms of irrigation. Not only are return flows high, but they are high in nutrients as fertilizer application is also highly inefficient when flood irrigation is practised. This combination of circumstances gives rise to lush vegetation growth downstream from the irrigation scheme, as water is now available throughout the year thereby changing the character of the ephemeral river by altering the flood pulse duration.
Keywords: ephemeral, irrigation, dam, flooding, return flow

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Vegetation and wildlife Eflows indicators in the Okavango River Basin: their relation to flows and their potential response flow variations
Bonyongo C.M., Curtis B., Roberts K., Santos C., Amado C.

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The Okavango River Basin supports a high diversity of flora and fauna that are variably related to flows of the basin river systems. The highest diversity of flora and fauna within the basin is found in the Okavango Delta. In view of the potential developments within the basin, an environmental flows assessment for the Okavango River Basin was conducted to establish potential response of vegetation and wildlife to flow variation. Flow related vegetation and wildlife indicators were identified based on available literature and expert knowledge of the basin wildlife and vegetation. Six wildlife indicators were identified for the whole basin. They are semi aquatics, frogs and river snakes, middle floodplain grazers, outer floodplain grazers and lower floodplain grazers. For vegetation, ten river indicators namely channel macrophytes, upper wet bank 1 (reeds), upper wet bank 2 (trees & shrubs), river dry bank, floodplain dry bank, floodplain residual pools, lower river floodplain, middle river floodplain and upper river floodplains. For the Delta, eight vegetation indicators were identified. They are open waters, permanent swamps, lower floodplain upper floodplain, occasionally flooded grassland sporobolus islands, riparian woodland and savanna/scrub. As expected, aquatic and semi aquatic indicators appeared to be more sensitive to flow variation. A development scenario analysis predicted that under low and medium water development scenarios, there will be no major deviation from the present day conditions of vegetation and wildlife, while a high water development scenario would significantly affect vegetation and wildlife, especially in the Delta. A high water development scenario would result in significant reduction of flows, and that will effectively change the floodplain vegetation which offers high quality grazing when the floods recede. The loss of floodplain ecosystems would definitely have negative impacts on floodplain grazers. However, major knowledge gaps were identified during the process, suggesting that long-term monitoring of the response of indicators to flow variation is an absolute necessity.
Keywords: Flow, wildlife, vegetation, Okavango basin

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Pulse flow of the Boteti River and its impact on large mammal populations and their conservation
Brooks C.J, Harris S.

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The Boteti River is a principal out flow of the Okavango Delta. The flow of water along the river pulses at irregular intervals in relation to regional rainfall and flood dynamics within the Delta. The river forms the western boundary of the Makgadikgadi Pans National Park, and during wetter phases the river forms a wide (30-80 m) flow of water that creates a physical barrier for the park boundary. However, during dry phases the river exists as a dry riverbed with dispersed waterholes along its course, providing vital drinking water for wildlife and cattle, but enabling transgression of the park boundary by both wildlife and cattle. We investigated the impact of resource competition between cattle and wildlife to determine if cattle were competing for grazing resources with wildlife, principally zebra (Equus burchelli antiquorum) and wildebeest (Connochaetes taurinus) and limiting their populations. Both the zebra and wildebeest populations have fallen dramatically over the past few decades. Our objective was to determine if a man-made barrier (wildlife fence) aligned along the river to replace the physical barrier of the flowing river would be of beneficial or negative impact to the local wildlife population. We found that there was a significant overlap in dietary preference between cattle and wildebeest in all of the habitats across which they both utilised, and to a lesser extent also between cattle and zebra. Cattle movement into the park across the dry riverbed may have excluded both zebra and wildebeest from preferred grazing close to waterholes. Zebra and wildebeest suffered increasing resource constraints and environmental constraints through the competitive effects with cattle, which may have had a predominant impact upon falling wildlife population numbers. We conclude that the erection of a fence along the alignment of the Boteti River will be of long-term benefit to the wildlife populations by excluding cattle from the Makgadikgadi Pans National Park.
Keywords: pulsing river, Boteti River, wildlife fence, zebra, wildebeest, cattle, resource competition

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Characterization of riverine floodplain habitats and benthic macroinvertebrates across a human disturbance gradient in Pennsylvania (USA) rivers
Brooks R.P., Yetter S.E., Bishop J.A., Wardop D.E.

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The Pulsing Paradigm: where science meets adaptive ecosystem management
Brown M.T.

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The Everglades: Pulsing on the edge of chaos
Brown M.T.

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Shaped by climatic pulses over millions of years, decadal cycles of drought and rain, annual cycles of flood and fire, and daily solar cycles, the Florida Everglades ecosystem is a wide, shallow wetland on the southern tip of the continental United States. The Everglades occupies a Pleistocene limestone shelf that was first inundated during the Jurassic Period and remained so through most of the Cretaceous Period. The Florida peninsula has been alternatively covered with seawater at least seven times since bedrock formed. The current Everglades ecosystem is approximately 5,000 years old. Subtropical in climate, the historical Everglades wetland covered the southern half of a watershed that began in the “highlands” (30 meters elevation, NGVD) of central Florida where the Kissimmee River collected surface runoff and flowed 75 kilometers southward to discharge into Lake Okeechobee, a vast shallow lake at about the midpoint of the basin. Excess wet season water in the lake would overflow the southern lake edge and form a slow moving "Everglades river-of-grass" about 100 km wide by about 160 km long that flowed southward to Florida Bay at the southern tip of Florida. The climate is characterized by a 7-month wet season from April through October within which about 75 percent of precipitation (1200mm) falls primarily from tropical cyclones and thunderstorms. Twenty-five percent (400mm) of the annual precipitation falls during the dry season from November to March; the result of frontal activity. Precipitation in August through October can be as much as double normal amounts due to tropical depressions, storms, and hurricanes. Tropical storms average one a year, and major hurricanes about once every seven to ten years. Growing, shrinking, dying, and reappearing within years or decades, the ecosystems of the Everglades are in constant states of change, driven by the pulsing of climate, seasonal wet and drought cycles, and the frequency of fire. Prior to human drainage activities, the Everglades was a web of sawgrass marshes, wet prairies and thinly treed cypress swamps totalling about 10,000 km² in size. The margins between ecosystems were subtle and often imperceptible as a consequence of the extremely flat terrain (sloping about 3 cm per kilometer, north to south), Today after many years of human dominance, much of the hydrologic pulse has been altered or removed completely. The waves of human populations migrating to southern Florida that began in the mid 1800's and have continued into the present resemble yet another set of pulses that have had profound effects on the hydrology and ecology of the Everglades. In the early years every effort was made to drain the Everglades to turn it into productive farmland. Later protection for the many human settlements that had sprang up throughout south Florida demanded dikes and levees. Still later, the Everglades became an important source of fresh water for the millions of people living on its eastern boarder, and management shifted toward water supply. With each of these initiatives, came changes in hydrology, which ultimately changed the ecosystem. The pulses of human management are not over, as currently governmental agencies in the name of restoration are spending unprecedented amounts of money and energy to undo many of the previous “improvements”. In this paper we will explore these pulses, their interaction, their ordering and disordering influences and develop a generalized model of pulsing systems that includes both externally and internally derived pulses of differing frequencies and intensities to explore the consequences of management which often has a single objective. Then we will explore Odum’s suggestion that “...if pulsing is general, then what is sustainable in ecosystems, is a repeating oscillation that is often poised on the edge of chaos” (Odum, Odum and Odum, 1995).
Keywords: Everglades, pulsed systems, order

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Flood pulse influences in the biogeochemistry dynamics of Paraguay River, Pantanal Wetland - Brazil
Calheiros D.F., Oliveira M.D. , Futter M.N.

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The Pantanal is one of the biggest wetlands in the world (about 160,000 km², with 140,000 km² in Brazil, 15,000 km² in Bolivia and 5,000 km² in Paraguay), forming the upper part of the Paraná-Paraguay River System, or the La Plata Basin, in the centre of South America. It has been designated a National Heritage by Brazilian Federal Constitution, Humanity Heritage and a United Nations Biosphere Reserve as it is still in pristine condition. Information on the spatiotemporal variability of inundation patterns is required to better understand and manage the hydrology, biogeochemistry, and ecology of the extensive floodplains of tropical regions such as the Pantanal Wetland. Water quality data have been collected sporadically, making statistical analysis more difficult. The main goal of this research is to estimate monthly and seasonal (rising, flood, falling and dry hydrological season) fluxes of water and nutrients in the Paraguay River, the main river of the Pantanal floodplain. Fluxes were estimated using daily records of the river level at Ladário Station (LD) collected by the Brazilian Navy since 1900, and an upper river station (São Francisco - SF) monitored by National Water Agency (ANA) where both discharge and water level have been measured. The SF water level:discharge relationship was used to estimate pro-rated flows at LD. Monthly water quality sampling for 30 parameters has been conducted for 20 years (1989-2009) just upstream of Ladário Station. In this introductory analysis we present trends in monthly and seasonal fluxes of water, nutrients (NTotal, NO₃, NO₂, NH₄, PTotal, and PO₄) and suspended sediments. The preliminary results showed that the dynamics of nutrients and sediments are correlated with discharge. Fluxes of PTotal and NTotal are strongly dependent on hydrology. Fluxes of NO₃ show a complex pattern related to hydrology. Droughts in the preceding season can have a major effect on PO₄ flux. This hydro-ecological understanding of nutrients dynamics can be used to project the effects of climate change on nutrient fluxes and to better understand the controls on primary and secondary aquatic production in the Paraguay River. Grants: LTER/CNPq
Keywords: Pantanal wetland, Paraguay River, flood pulse, nutrients

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Gradient Spectral Analysis of Hydro-Ecological Seasonal Variation in the Pantanal Wetland, Brazil
Calheiros D.F., Oliveira M.D., Dantas M., Rosa R.R.

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The Pantanal wetland is one of the largest wetlands in the world (ca. 140.000 km2), considered as a National Heritage by the Brazilian Federal Constitution and Humanity Heritage and Biosphere Reserve by the United Nations. For understanding the hydrology, biogeochemistry, and ecology of the extensive floodplains of tropical regions, such as Pantanal Wetland, information is necessary regarding the spatial and temporal variability of inundation patterns, and also essential to managing this complex ecosystem. Most of the time series of water quality data collected from this natural system result in partial data set, thus compromising the performance of usual statistical analysis. The main goal of this research is to apply a new computational methodology for short time series analysis, showing non-linear behavior in the time, amplitude and frequency domains to understand the hydro-ecological functioning of this river-floodplain system. The applied methodology, called Gradient Spectral Analysis (GSA), combines two mathematical techniques, the so-called Gradient Pattern Analysis (GPA) and the Wavelet Multiresolution Analysis (WMA). The GSA classifies different non-linear regimes taking into account short time series samples generated from dynamic processes previously associated with chaotic and stochastic models, and classifies the pattern variability from high to low scaling and asymmetry fluctuation. We classified short times series (240 events) related to long term hydro-ecological research of the Paraguay River, the main river of the Pantanal floodplain. The data set is based on hydrological monitoring at Ladário Station, carried out daily by the Brazilian Navy since 1900, and the monitoring of 30 parameters of water quality, sampled monthly during 20 years (1989-2009). Initially we correlated the seasonal variation of the river level records with the variation of 5 main limnological parameters. The preliminary results showed that the dynamics of Dissolved Oxygen and Electrical Conductivity were correlated directly with the River Level, the dynamics of Dissolved Carbonic Gas and Total Phosphorus were very close, but Total Nitrogen presented a larger distance, showing high asymmetry. Based on these first round results, there is a good indication that this analysis will be robust enough for the prediction of behavior variables for further application on climate change forecasting and correlation with primary and secondary aquatic production. Grant: LTER/CNPq
Keywords: Pantanal Wetland, Paraguay River, Limnological data, Gradient Spectral Analysis

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Anthropogenic impacts influencing the hydro-ecological processes of Pantanal Wetland - Brazil
Calheiros D.F., Oliveira M.D., Padovani C.R.

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The Pantanal Wetland is an extensive floodplain in the centre of South America, belonging to the Paraná-Paraguay River System. It is one of the biggest wetlands in the world, recognized as a National Heritage by the Brazilian Federal Constitution, and Humanity Heritage and Biosphere Reserve by United Nations as it is still in a good level of conservation. The Upper Paraguay River catchment area covers about 496,000 km² and the Pantanal about 160,000 km², which is shared by Brazil (80%), Bolivia and Paraguay (20%). The livelihood of pantaneiros in the floodplain area relies on the environmental health and maintenance of the natural hydro-ecological processes. The main economic activities are cattle ranching, subsistence and professional fishery, as well fish catch tourism. However, in the Brazilian area the use of natural resources, mainly in the surrounding plateau, is taking place in an unsustainable way. Despite that 85% of the Pantanal floodplain still remains with the original vegetation cover, land use impacts in the high lands as deforestation (60-80% converted to pasture, soy bean, cotton, sugar cane and corn crops), erosion, sedimentation, contamination (primarily pesticides and urban and agroindustrial sewage) have occurred since 70’s. The values of total suspended matter achieve as high as 5,000 t/day in the Cuiabá River and 11,000 t/day in the São Lourenço River during rainy seasons. The contamination of pesticides includes recent use of DDT, a forbidden substance in Brazil, and other toxic substances for fish as λ-cyhalothrin. Sedimentation is occurring in all main rivers that form the floodplain, mainly in the Taquari River where about 5,000 km² are permanently flooded, resulting in alteration of the natural flood pulse. However, the main problem is the high number of planned dams in the main tributaries. It is crucial to change, as fast as possible, the hydrological regime of the dams already built to a more ecological one and leave some catchments free of them. This recent expansion of electric power dams (29 current and more 86 dams to be build = 115 projects), mainly small ones (≤ 30 MW) in the northern part of the basin (ca. 70% in Mato Grosso State), is already in progress. The synergic impacts of all dams will influence the water dynamics in the whole wetland, since the upper basin is responsible for 75% of the water’s system. To minimize those impacts, it is necessary to rethink the development of the region, based on integrated and participative planning and management taking into account the all catchment area. Changes in the crop/cattle production practices also need be rethought, following the environmental legislation related to protect riparian forest and springs, putting in action a strong program of recovering degraded areas, as well as implementing agro-ecological production systems in the surrounding plateau. If the wise use of natural resources were not put into practice, the hydro-ecological processes of the Pantanal wetland will be deeply changed, losing the environmental services in quantity and quality such as fish production. All those impacts together are interfering negatively in its ecological processes, resulting in actual and potential environmental and social problems. Grant: LTER/CNPq
Keywords: Pantanal Wetland, Environmental impacts, deforestation, dams, contamination

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Global Sensitivity Analysis of the Pitman Rainfall-Runoff Model in the Okavango Basin
Cathey A.M., Munoz-Carpena R., Hughes D.

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The Okavango Basin and Delta comprises a unique hydrologic system that delivers an important flood pulse for wildlife and humans from humid Angola to semi-arid Namibia and Botswana. The Angolan portion of the Basin contributes that vast majority of the rainfall and occupies 60 percent of the 192,500 km2 system. Understanding the hydrologic dynamics in the upstream contributing basin is crucial for understanding the flooding within the Delta. Rainfall and flow data is largely unavailable for much of the contributing watershed over the past 30 years. The Pitman model, which is embedded in the GIS user interface SPATSIM, has been used to model the river flow in the Okavango River. This is a rainfall runoff model that has recently been updated to incorporate groundwater storage. The model was calibrated on data from 12 years of data and tested on an additional six years. Global uncertainty and sensitivity analyses were conducted through this research in order to quantify model reliability along with parameter importance. Each of the 41 input parameters in the Pitman model is examined for first and higher order sensitivities and the total model uncertainty is determined. Numeric ranges for the input parameters are determined through literature values and expert opinion. The Morris Method is a qualitative sensitivity analysis technique that is used to screen the input parameters in order to detect those that are the most sensitive. The variance based extended FAST quantitative uncertainty and sensitivity analysis method is then used on the subset of most sensitive parameters. The two-step global sensitivity and uncertainty analysis enables all of the model input parameters to be investigated through a computationally intensive quantitative method while at the same time minimizes the computational requirements by focusing on the most sensitive parameters in the final step. The output function for analysis is the flow at the inlet of the Delta. This global uncertainty and sensitivity analysis of the Pitman model in the Okavango Basin will aid managers, scientists, and modelers in making decisions regarding the risk of development scenarios and allocating monitoring resources as well as improve our overall understanding of the system. Managers can be informed of the model reliability and the uncertainty associated with model predictions. This information will allow a risk assessment when considering the outcomes of development scenarios. Furthermore, in order to improve future model results, the determination of the most sensitive and uncertain parameters may become the focus of monitoring efforts.
Keywords: hydrologic modeling, uncertainty analysis, sensitivity analysis, pitman model, okavango

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ITK Asset Base, Livelihood Security and Sustainable Rangeland Management in a Flood-Pulsed and Climate Variable Basin – The Case of Mopipi and Mokoboxane in the Boteti Sub-District, Botswana
Chanda R., Darkoh M.B.K., Segosebe E.M., Magole L., Atlhopeng J.R., Mulale K.

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How Internal Processes Affect Resilience to State Change in High-Disturbance Wetland Ecosystems
Childers D.L., Grimm N., Heffernan J., Minckley T., Vivoni E.

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Ecosystems experience regime shifts in response to both natural and human-induced disturbances. Much of our knowledge about regime shifts comes from ecosystems with relatively benign disturbance regimes (e.g., lakes), yet alternate stable states are more often found in disturbance-structured ecosystems. We are addressing theories of ecosystem regime shift and stable state resilience by studying aridland wetlands (ciénegas). These wetlands are effectively ecosystems “on the edge”—systems in an environment very nearly too dry for wetlands, yet routinely perturbed by scouring floods. Our overarching question for this new research initiative is: Can internal processes in ecosystems with substantial disturbance regimes enhance resilience to state change that is driven by exogenous perturbations? Our experimental work addresses a more specific central question: Does release from resource limitation enhance the resistance of ciénega ecosystems to flooding or drying disturbance, thereby reducing susceptibility to state change, by altering allocation of aboveground and belowground biomass and production? We address this question using hydrological, ecological, biogeochemical, and paleoecological approaches in five ciénega ecosystems in the southwestern U.S. and Mexico along a flash-flood disturbance gradient. Central to our research is the hypothesis that enhancing nutrient availability will reduce belowground production (total and as fraction of total production) in aridland wetlands that experience minimal/no flooding, fitting resource allocation theory, but will stimulate belowground production in wetlands with a flooding regime, contrary to allocation theory. Our primary response variable is an index of aboveground and belowground plant biomass and production. We are also quantifying: 1) plant community composition; 2) nutrient dynamics in soils, sediments, and hyporheic water; 3) soil/sediment oxygen and microbial activity; 4) soil/sediment accretion and erosion; 5) surface and subsurface hydraulics and canopy flow, and; 6) the efficacy of wetland restoration in aridland streams. Our historical research at all five sites is investigating the origination of ciénega development, state change responses to floods and climate variability, and vegetation changes through the late Holocene. Finally we are using an existing catchment model to characterize the late Holocene history of flood frequency at all sites, and integrating the output with our paleoecological analyses. We have adopted a conceptual framework based on a stability landscape defined by two hydrologic axes—flooding and drying—and a third internal process axis represented by biomass and productivity allocation in wetland plants. Our process-based, interdisciplinary experimental approach is advancing theory on ecosystem resilience and state-change thresholds while also providing practical knowledge on the restoration of ciénega ecosystems—a unique and threatened component of aridland streams throughout the world.
Keywords: ecosystem resilience, state change, aridland wetlands, pulsed flooding, productivity, biogeochemistry, hydrology, paleoecology

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Health Implications of hydro-climate variability and change in the Okavango Delta
Chimbari M.J.

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Responding to flood pulsing challenges in the Okavango Delta
Chimbari M.J., Ringrose S., Bonyongo C., Magole L., Masamba W., Kgathi D., Mbaiwa J.

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The Harry Oppenheimer Okavango Research Centre (UB-HOORC) was established in 1992 following the decision by the Government of Botswana to abandon its intended project aimed at expanding access of waters from the Okavango Delta to downstream communities. The decision was timely as the Delta then went into a major drying cycle which lasted from the early 1990s to early 2000 when the floods began to return to the outflow section of the Delta. This positively impacted a large proportion of the over 100 000 people who depend on the floodwaters. The decadal flood pulse has since underpinned much of HOORC’s research either directly or indirectly as the extreme variability of flow has to be built into the reality of sustainable management and hence forms the mandate of HOORC. To fulfil its mandate HOORC defined its operational objectives in a way that addressed all the key determinants for sustainable management of the Okavango Delta. Thus, HOORC’s research focuses on flow variability as this relates to fluxes at the land-water interface, ecosystem dynamics, livelihood adaptations including tourism and governance interventions. This paper describes the evolution of HOORC as it adapted to better address its mandate, highlights major research contributions towards the improved management of the Okavango Delta and emphasizes how HOORC is transforming itself to meet future research challenges. Key research outputs in the areas of climate change, flow variability characterization, the valuation of ecosystem services, impacts of tourism and governance issues are reviewed. Furthermore, HOORC’s has interactions with decision makers and communities at various policy levels are highlighted. The paper concludes by considering HOORC’s future role in the context of a transforming University of Botswana and ongoing/intensifying climate change related challenges faced both by the Okavango Delta and Kgalagadi dry ecosystems.
Keywords: sustainable management, climate change, Okavango Delta, Harry Oppenheimer Okavango Research Centre

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A method for distinguishing different water sources during flood events in river floodplains, northern Poland
Chormański J., Karalevich J., Kardel I., Okruszko T., Wassen M.

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The Biebrza wetlands are located in an ice-marginal valley in northeastern Poland and cover some 195 000 hectares. The Biebrza river is not regulated, the valley is not reclaimed and still has marsh, fen and grassland vegetation whereas large scale human interventions in hydrology are absent. The most characteristic feature of the Biebrza river is flooding, which occurs almost every year during the spring thaw. During these floods the inundated wetlands covers many km². This water may in principle derive from three different sources: 1) rain and snow-melt water, 2) river water and 3) groundwater. We developed a method to distinguish these water sources enabling us to estimate the area inundated by the different water types. Our analysis was based on long term monitoring of water levels via gauge stations and an in depth analysis of floods for the period 2001-2008. We used Landsat images, field surveys during floods and chemical analysis of water samples. The satellite images of the Landsat 5 TM and the Landsat 7 ETM+ captured during maximum flood were processed. This included the calculation of ratio of bands 7/4, the Normalized Differential Vegetation Index (NDVI) and a Principal Component Analysis (PCA). The results of these transformations were stored in new bands and were classified by using the maximum likelihood classifier for identification of inundated areas. The image of 2002 was verified with high overall accuracy on the basis of 796 sample points. Samples obtained from hydro-chemical transects were statistically analyzed using PCA. The results of the statistical analysis were imported to ArcGIS. Geographical analysis resulted in maps depicting the spatial distribution of the first three principal components. K-means cluster analysis was performed by establishing clusters, which finally were interpreted as representing the three different water sources: river, groundwater and snowmelt. Validation was performed by comparing the results with vegetation maps. There was a good match between water sources and generalized vegetation maps. We conclude that the method was demonstrated to be useful for analysing vast floodplain wetlands in which it is relevant to know the spatial distribution of different water sources during inundations. In the case of ecological studies aiming at conservation/restoration of habitat condition within floodplain wetlands, there is a need to know the balance between water from different sources. Distinguishing different water sources during inundation of river floodplains is also important for constructing and verification of floodplain hydrodynamic models.
Keywords: wetlands, water source, remote sensing

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Hydrologic Thresholds and the Persistence of Landscape Pattern in the Everglades
Cohen M.J., Watts D.L., Heffernan J.B., Osborne T.Z.

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Many wetlands exhibit self-organized spatial patterns in which biotic feedbacks create a patchy landscape mosaic, which in turn greatly enhances overall habitat value. The underlying feedbacks that create pattern are scale-dependent; that is, pattern emerges from the coupled action of local positive feedbacks and distal negative feedbacks, the spatial characteristics of which determine pattern geometry. The feedbacks that create and maintain patterned wetlands are almost always linked to reciprocal biotic controls on hydrology (e.g., via peat accretion or sedimentation) or nutrient redistribution (e.g., via evaporative gradients or flow convergence). Since hydrologic changes and nutrient enrichment are most frequently the wetland attributes impacted by human activities, and because landscapes can shift catastrophically from patterned to homogeneous states with changes in exogenous drivers, understanding the link between hydrology and pattern persistence or loss is integral to ecosystem management. The ridge-slough-tree island patterned peatland mosaic is among the most important and charismatic features of the Everglades. Determining the hydrologic conditions (hydroperiod, water level mean and variance, flow velocity) under which the feedbacks controlling landscape pattern are preserved is critical to restoration. Ongoing work shows that catastrophic pattern loss occurs along multiple axes of hydrologic modification, underscoring the need for a more comprehensive link between hydrology and ecosystem condition than can be provided by simply setting minimum flow requirements. This talk will examine the three primary mechanisms that underly pattern formation in this landscape: the presence of multiple peat accretion equilibria, the distal effects of peat accretion on landscape discharge, and the animal-induced redistribution of phosphorus. Further, it will explore the hydrologic thresholds (too dry, too wet, too stable) that lead to catastophic pattern loss, and propose hydrologic targets (flows, levels, variances) for the restoration and maintenance of landscape pattern.
Keywords: patterned landscape, Everglades, environmental flows, self-organization

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Bird distribution in the Okavango Delta in response to flood variability
Cooper-Mullin C., Hancock P., Ramberg L.

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Carbon Sequestration and Nutrient Retention in Tidal- versus River-pulsed Floodplain Forests
Craft C.B.

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I measured soil organic carbon (C) nitrogen (N) and phosphorus (P) pools and accumulation in tidal and non-tidal floodplain forests of the southeastern U.S. to compare the importance of pulsing frequency and duration on C sequestration and nutrient retention. Soil cores were collected from tidal and non-tidal reaches of the Altamaha River, Georgia, the third largest river on the US east coast and the largest un-dammed river along its mainstem. Percent organic C and N (0-30 cm) were nearly ten times greater in tidal (21% C, 1.27% N) than non-tidal floodplain forest soils (2% C, 0.14% N). Soil total P was two times greater in tidal forests (590 ug/g) than in non-tidal forests (200 ug/g). Because of its high organic matter content (42%), bulk density was five times lower in tidal (0.26 g/cm³) versus non-tidal forest soils (1.27 g/cm³). ¹³⁷Cs soil accretion did not differ between tidal (1.0 mm/yr) and non-tidal (0.7 mm/yr) floodplain forests. Soil organic C and N pools (0-30 cm) were two times greater in the organic-rich tidal forest soils (546 g C/m², 33 g N/m²) relative to the mineral soils of the non-tidal floodplain forests (241 g C/m², 19 g N/m²). Phosphorus pools, however, were greater in non-tidal forest soils, 2.68 g/m² versus 1.53 g P/m² in tidal forest soils. Because of their high organic matter content, tidal forests had higher rates of C sequestration (42 g/m²/yr) and N accumulation (2.7 g/m²/yr) than non-tidal floodplain forests (28 g C/m²/yr, 1.9 g N/m²/yr). Phosphorus accumulation did not differ between tidal and non-tidal forests (0.22-0.23 g/m²/yr) whereas sediment accumulation was greater in the non-tidal floodplain forests, 490 g/m²/yr versus 300 g/m²/yr in the tidal forests. Tidal floodplain forests, because they are inundated more frequently and for longer cumulative duration during the year, sequester more organic C and N than non-tidal floodplain forests that, while inundated during the spring flood pulse, are dry much of the year which allows soil organic matter to oxidize to CO₂. Non-tidal forests, however, are more important sinks for sediment that is deposited when floodwaters inundate the wetland during the spring flood pulse.
Keywords: Water quality, nitrogen, phosphorus, sediment

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Exploring scenarios to restore the Kirua Swamp in the Pangani River Basin, Tanzania
Cross K., Clark B., Kamugisha S., Sadiki H., King J., Brown C., West K., Turpie J., Mwendera E.

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Flooded plain wetland management in China and its response to flooding
Cui Lijuan

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Monitoring wetland health using aquatic macroinvertebrates: Generating and applying the data
Dallas H.F., Mosepele B.

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Biomonitoring is recognised as a useful tool for determining the ecological health of aquatic ecosystems. It is based on the concept of biological integrity and use is made of biological indicators and indices developed using biotic components of the aquatic environment. Tools for assessing wetland health of the Okavango Delta based on aquatic macroinvertebrates were examined in a pilot study in two focal areas within the Moremi Game Reserve. The study focused on one specific aquatic habitat, namely the vegetation of channel margins, which was distinguished on the basis of flow (out-of-current and in-current). Aquatic macroinvertebrates were sampled during July and October 2008, representing the high and low flow periods. Sites were further differentiated into reference sites, i.e., least disturbed; and monitoring sites, i.e., exposed to anthropogenic activities. Data were analysed to determine the extent of the spatial and temporal variation in macroinvertebrate assemblages. Spatial differences in number of taxa, macroinvertebrate assemblages and frequency of occurrence were observed at both the level of focal area (Nxaraga and Xakanaka) and aquatic habitat (marginal vegetation, in- or out-of-current), although this was not always consistent from one area to another or one habitat to another. Temporal differences were also observed but this was in relation to the number of taxa and not the assemblage, with more taxa generally occurring in October compared to July. Whilst these results seem to complicate the interpretation of bioassessment data, it was nonetheless possible to generate a prototype Index of Biotic Integrity (IBI) based on aquatic macroinvertebrates and to test and refine the prototype biotic index, the Okavango Assessment System (OKASS) developed previously. The utility of two approaches for interpreting data, namely an IBI and OKASS, were compared. Generally, monitoring sites that had a higher degree of human disturbance were distinctly different from comparable reference sites, while monitoring sites that had intermediate to low human disturbance scores varied in terms of their difference from comparable reference sites. This suggests that natural spatial variation of macroinvertebrate assemblages at reference sites masked the detection of impairment at slightly impacted monitoring sites. In addition, it suggests that faunal assemblages have not changed noticeably at mildly impacted sites. It may also suggest that the taxa occurring in the Delta are not sensitive enough to indicate mild impacts, or that the resolution, namely family level, is not sensitive enough to distinguish between subtle changes prevalent at mildly impacted sites. The information collected and analysed in this pilot study should provide a solid basis for future monitoring of wetland health using aquatic macroinvertebrates. The development of two complementary methods means that future bioassessment data may be interpreted using both methods. This will allow the prototype methods to be evaluated and improved upon.
Keywords: biomonitoring, aquatic macroinvertebrates, habitats, reference sites, Index of Biotic Integrity, biotic index, OKASS

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Variation in hydroperiod drives aquatic biodiversity in the Okavango Delta
Davidson T., Mackay A., Mazebedi R., Todd M., Wolski P.

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The Okavango Delta is a pristine wetland of international importance. Notwithstanding a lack of endemism and relatively low species richness at individual sites the aquatic biodiversity of the delta is crucial to the value of the delta. The complex mosaic of habitats results in high between-site differences in species composition. Here we present a synthesis of biological diversity data sampled as part of the DARWIN initiative project running from September 2006 - to April 2009. A number of elements of aquatic biodiversity were sampled, including diatoms, macroinvertebrates and submerged macrophytes. Baseline water chemistry was determined seasonally for each site. In addition, Landsat (5 and ETM) satellite images were used to generate 16 inundation maps depicting maximum annual inundation extent during years 1989-2007 (excluding 1991 and 2003) from which we derived the hydrological variables of flood and hydroperiod. Flood is a measure of the number of times a site has flooded over the last 15 years and hydroperiod is an index of the number of months of inundation and the amplitude of water level change over the last 15 years. Sampling sites were situated in four focal areas, in the upper pan-handle, in the lower pan-handle, Xakanxa and the Boro and a number of habitat types were included. Sampling was undertaken 5 times covering each phase of the flood pulse. Multivariate statistical methods were employed to determine the chief controls on biodiversity and assemblage composition. The composition of the unicellular algae, diatoms, were chiefly controlled by calcium, silica and hydroperiod. Macroinvertebrate assemblages were structured largely by habitat and hydroperiod. The submerged macrophyte flora of individual sites was determined largely by potassium concentration and hydroperiod. The chemical variables, such as Ca and K, which explained large proportion of the variance in the diatom and macrophyte assemblages respectively, were strongly correlated with hydroperiod. Thus, even where hydroperiod was not singled out as the principal controlling variable, it is likely to drive the variation in the variable that the multivariate model identified as the major structuring factor. In conclusion, the beta diversity of biological assemblages at a number of trophic levels in distinct habitats such as lagoons, main channel, permanent floodplain, seasonal floodplain appears to be reliant on the variation in flood regime between years. The recent development of hydroperiod as a semi-quantitative estimate of duration and amplitude of flooding for all areas of the delta has made analysing the relationship between an index of flooding and the aquatic flora and fauna possible for the first time.
Keywords: Freshwater Biodiversity, Hydroperiod, Diatoms, Macroinvertebrates, Macrophytes

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Biodiversity in flood-pulsed wetlands
Day J.

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While we usually think of flood-pulsed wetlands as being large and perennial (the Okavango and the Amazonian várzea, for instance) strong fluctuations in water supply and therefore in accompanying chemical and biological conditions are characteristic of smaller and temporary wetlands too. Differences in the magnitude of such fluctuations and in geomorphology together create a wide range of types of flood-pulsed wetlands from small rock pools and tree-holes to extensive pans and major floodplains. We also tend to think of ecosystems affected by strongly fluctuating conditions as being ‘harsh’ and stressed and, by implication, supporting relatively low levels of biodiversity. In fact, as long as the fluctuations are predictable, and have been predictable for long enough for their biotas to become adapted to them, conditions in pulsed systems are often conducive to the development of relatively high levels of biodiversity. Stress is in the eye of the beholder, rather than the denizens, of non-perennial systems. Overall numbers of taxa may be greater still in systems where water does not disappear completely because two rather different assemblages may occur at the high and low points of the hydrological cycle. Physical perturbation of flood-pulsed systems by humans is usually the result of modifying the hydrology. Consequences for the biota can be severe in systems where the biota is adapted to a particular hydroperiod and because changes in hydrology are usually accompanied by changes in the type and quantity of resources entering the system. Climate change will modify rainfall as well as temperature. We can predict that temperature effects will be greater than hydrological ones in flood-pulsed wetlands that experience wetter conditions in future. In systems in which less water becomes available, the biotas of permanent wetlands are likely to be threatened more by reduced quantities of water, and less predictable hydrological cycles, than by increased temperatures. In contrast, those of temporary wetlands are already adapted to surviving drought as desiccated propagules of one sort or another and if anything, their ranges will increase as perennial wetlands become seasonal.
Keywords: biodiversity adaptation perturbations

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Government response to the immediate impacts of the 2009 high floods in the Okavango Delta
Dube O.P.

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Floods are part of the hydro-meteorologically triggered disasters, which include tropical cyclones, drought, wild fires, dust storms, pest plagues etc. Among these, drought has been the most commonly experienced in Botswana. As a result, Government structures for dealing with drought are more developed, although the approach remains largely reactive. In contrast, experience in dealing with floods is limited because these are comparatively rare events in Botswana’s semi-arid environment. However, this scenario may change, given the projected increase in climate variability due to climate change. The National Disaster Management Office (NDMO) in the Office of the President is the main body within Government tasked with the responsibility of managing natural and human induced hazards and disasters such as the 2009 Okavango floods disaster which displaced numerous villages and also affected Government structures and schools. The philosophy of NDMO in dealing with disasters is that “disaster risk reduction (DRR) is everybody’s business” and the role of NDMO is to coordinate disaster risk reduction activities by different Ministries, sectors and other stakeholders e.g. NGOs. The NDMO therefore worked closely with the District Disaster Management Committee (formed by officers from different Ministries) that was supervised by the District Commissioner, to determine the severity of the floods and the interventions required. These interventions included among others evacuation to safer areas, provision of shelter and food and attending to numerous stresses emanating from such displacement. The NDMO, with the support of the Office of the President, played a critical role during the floods disaster of securing and coordinating resources from Government, private sector and the Red Cross and in facilitating delivery of these resources to the affected areas as well as keeping the nation at large informed and linking to other organizations outside Botswana that could be of assistance. The NDMO is currently working with different Government departments to put greater emphasis on disaster prevention.
Keywords: Government response, flood impacts, disaster management, Okavango

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A strategic framework for maintaining the ecological character of Australia’s tropical wetlands
Finlayson M.

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A strategic framework for monitoring natural and human-induced change in the pulse-flow wetlands of the coastal plains of northern Australia is presented. The framework provided a basis for ongoing environmental investigations and also supports methods used to monitor the vulnerability of the coastal wetlands to change, including climate change and sea-level rise. The information derived through the framework has been used to assess scenarios, highlight the potential significance and implications of changes, and assist land managers formulate management responses. As a consequence of the investigations associated with the framework questions have been raised about the importance of natural drivers of change compared to anthropogenic drivers, such as the occurrence of alien, invasive species – questions that have proven difficult to answer. The framework incorporates large-scale studies for monitoring atmospheric and hydrodynamic processes as well as mapping and monitoring environmental change in the freshwater wetlands and the floodplains. In undertaking these analyses a conceptual ecological model of the wetlands was developed and used to assess the importance of the processes that underpin the ecological character of the wetlands. Monitoring was proposed to address processes influencing the stability and rate of change of the floodplain environments. These include largescale processes, such as inter-annual variability in weather conditions affecting the morphology of the coastal plains, shoreline and riverbank stabilisation, headward expansion of tidal creeks, and salinisation of freshwater basins. Information management was also addressed and a Geographic Information System structure proposed for effective data collation, analysis and management to facilitate data sharing and participation of multiple agencies and organisations interested in wetland change, especially where a landscape perspective or whole ecosystem approach is advocated. The usefulness of the framework within a complex and multi-dimensional social environment is discussed and salient lessons drawn, including those relating to the perceptions and realities of power and managerial responsibility.
Keywords: wetlands management, Australia, tropical wetlands

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Analysis of ecosystem services in pulse-flowed wetlands in northern Australia
Finlayson M., de Groot R.

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A framework for the analysis of the ecosystem services provided by pulse-flow wetland and riverine ecosystems of northern Australia was developed to assist with the analysis and assessment of trade-offs between different and at times conflicting socio-economic and cultural values. The knowledge base was derived from a mix of indigenous and non-indigenous sources with the former tending to focus more on cultural and the latter on economic values. The analyses focussed on the Daly and Mary River catchments and identified over 15 different services, of which four were economically most valuable, namely, carbon sequestration, water use, agriculture/horticulture and tourism. The economic benefits provided by these services were estimated at approximately A$50.7 million/year for the Mary River catchment (approx A$450/ha) and approximately A$82 million/year for the Daly River catchment (approx A$230/ha). These are relatively low figures compared to values for other wetlands which on average are estimated at US$3000 (approx A$4000) per ha/year, partly caused by the fact that only a few services were studied economically. A policy analysis highlighted the sectoral and integrated effect of policies and institutions on the wetland services and indicated discrepancies between higher-level strategies and management practices. The implications for management were explored by highlighting potential trade-offs and decision-making processes that could encourage consensus and communication between stakeholder representatives and government agencies. Further insight into the spatial distribution of the wetland services is required to support more analysis of the possibilities and constraints for multi-functional use of the catchments, especially when dealing with proposals to regulate the water flows in the rivers. As the latter has proven controversial, it is proposed that more detailed analysis is needed of selected ecosystem services, or individual categories of policies to see how these affect and/or are affected by different factors at different scales including national responses to climate change, including potential conflicts between proposals for water resource development and regulation.
Keywords: environmental services, pulsed-flow wetlands, northern Australia

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Determinants of ungulate biomass in grazing ecosystems: The importance of scale, floodpulses and habitat connectivity
Fynn R.W.S.

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Maximizing the intake of protein and energy is critical for productive ungulate populations. Strong declines in forage quality in the dry season means that ungulates need a high quality growing-season resource to put on as much fat and protein in the wet season as possible to allow for sufficient body stores during the dry-season protein and energy deficit. In addition, high quality forage is needed by lactating females during this period of greatly increased nutrient demands. During the dry season ungulates have to find some quality forage to minimize the rate of decline in their body stores. Significantly larger ungulate populations can be sustained in regions where they are able to migrate into regions that provide green grazing during the late dry-season, such as after the recession of floodwaters on floodplains or in areas that receive a large proportion of their total rainfall during the dry-season. In addition, productive herbivore populations can only be sustained where lactating females are able to track large-scale stochastic pulses in high quality forage during the growing season associated with patchiness of fire and rainfall in regions of high soil fertility (the resource heterogeneity effect). Owing to the ability to track stochastic pulses in quality forage at large scales, ungulates do not always return to the same sites each year resulting in better resting of the forage resources (the trophic decoupling effect), which combined with severe (but transient) grazing, trampling and dunging effects of large herds in large-scale migratory systems, accelerates nutrient cycling and primary productivity, while improving grassland structure and forage quality (the herd effect). Thus ungulates are able to increase their own carrying capacity at large scales. In addition to forage quality, ungulates also have to consider predation risk. Migratory herbivores experience greater decoupling from their predators than sedentary herbivores through the suppressive effects of migratory movements on predator populations, lower dispersion amongst the regional predator population and greater ability to select habitat that minimizes predation risk (the trophic decoupling effect). Loss of the ability to select foraging sites at large scales often results in greater ungulate-predator coupling and a decline in the ungulate population. This paper discusses the theory of angulate baiomass, raising research questions in the context of the pulsed and stochastic nature of quality forage in the Okavango region as influenced by the flood pulses, resource heterogeneity and the stochastic nature of rainfall in the outlying woodland regions.
Keywords: migration, adaptive foraging, resource heterogeneity, green forage

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Developing and Nurturing River Basin Governance
Gabaake G.

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Public and Private Partnership in Cultural Tourism – Case Study of Tsodilo Community Development Trust.
Gaborekwe R., Magole L.

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Hydrology of Nyanza Gulf and its influence on nutrient dynamics and functional capacity of Nyando wetland system
Gikuma-Njuru P.

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Fate of nutrients in floodplain lakes under the hydrological regime of a temperate climate zone in central Europe
Glinska-Lewczuk K., Burandt P.

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The ultimate characteristic of floodplain lakes is their exceptional hydrological and hydrochemical variability. Any floodplain ecosystem undergoes hydrological processes, which together with management practices at a catchment level, regulate nutrient loading reaching aquatic ecosystems. A defining characteristic of temperate floodplain lakes in central Europe, opposite to e.g. the tropics, is their seasonal but generally unpredictable hydrological cycle underpinned by relatively variable meteorological conditions. Rivers in northern Poland represent the mixed type of hydrological regime (sensu Pardè, 1933) with the annual pattern of two periods of high flows separated by two periods of lower activity of water. The first period – the main one, occurs in mid-winter (January-February) or spring (March-April) due to snow melt and is responsible for the highest peak flows, whereas the second period is the result of intensive rains during summer (June-July). Summer floodplain inundations are relatively rare and when they appear, they are superimposed by other factors e.g. channel overgrowth. This cycle can range from isolated, very shallow or even desiccated water bodies during the dry season, to much deeper water bodies inundated by a major river, local runoff and precipitation. A lake’s dimensions can increase orders of magnitude in volume and surface area, to become indistinguishable from waters inundating the floodplain. Nevertheless, the two genetic types of flood have different and individual consequences for the water quality in floodplain ecosystems. We assumed that the variable hydrological conditions imposed by the flood pulse on floodplain lakes underpin a pronounced seasonal response in chemical composition of water. The results of the 4-year research (2005-2008) conducted on 23 floodplain lakes located along meandering sections of three young-glacial river valleys (Lyna, Drwęca and Slupia) in northern Poland, showed that the flood pulsing alters both morphometry and water quality of floodplain lakes. The comparison of the following parameters: water temperature, dissolved oxygen, electrical conductivity, and pH as well as N03-N, NO2-N, NH4-N, SRP (soluble reactive phosphorus), TP-total phosphorus as well as cations (Ca2+, Mg2+, Na+, K+), anions (Cl-, SO42-, HCO3-) and total dissolved matter exhibited significant differences between water examined during spring and summer floods. Nonetheless on a genetic type of flood, high water levels (floods) contributed to the increase of water aeration and the dilution of the majority of ions in floodplain lake water. At all sites during spring inundations, we observed more significant aeration of water (even oversaturation) than during summer. Although the flood water is a significant source of nutrients, the ions of geochemical origin (Ca2+, Mg2+, SO42-, HCO3-) showed statistically lower concentrations during spring inundations when compared to summer floods. Biotic components of the floodplain ecosystems significantly changed response of overgrown lentic ecosystems to summer flood waters. A permanent hydrological connectivity to the river channel diminished the effects of flood on water quality in lakes of permanent water exchange.
Keywords: floodplain lake, hydrological regime, flood, temperate climate, aeration, nutrients

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Maputaland's Swamp Forests And Floods: Is the Stage Set for Rapid Change? (South Africa)
Grobler R.E., Grundling P., Price J.P., Grundling A.T., Bredenkamp G.J.

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Hydrological landscape setting of the oldest fen in Africa (Mfabeni, South Africa)
Grootjans A.P., Grundling P.L., Price J.S.

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The nature of flood events in the Mfabeni mire and implications for sustained flow to the Lake St Lucia Estuary, South Africa
Grundling P., Price J.P., Grootjans A.P.

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The Role of Pulsing Precipitation Events in Maintaining Wetlands on Primary Aquifers in South Africa
Grundling A.T., Price J.S., Malherbe J., van Zyl D., Grobler R.

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The response of a Tonle Sap-Great Lake system fishery to annual flood pulsing
Halls A.S., Paxton B.R., Ngor P.

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Large floodplain-river ecosystems around the world driven by a single annual flood pulse and supporting important commercial, artisanal and recreational fisheries are coming under mounting pressure to meet multi-sectoral demands. Many of these systems intersect international boundaries and are located in regions with developing economies where water storage infrastructure and hydropower facilities form central components of national and regional development strategies. Under natural flow conditions, the annual flood pulse in floodplain-rivers promotes the lateral transport of water, nutrients and organisms across the aquatic-terrestrial interface which enhances their biological productivity. Hydrological manipulation by water resource infrastructure alters the magnitude, duration and timing of the flood pulse reducing this productivity. The Tonle Sap-Great Lake (TS-GL) system in Cambodia is the most distinctive hydrogeomorphic feature in the Mekong River Basin. The Great Lake itself is the largest wetland in southeast Asia and supports one of the most productive inland fisheries in the world. Flow regulation by hydropower dams currently being proposed for construction upstream of the TS-GL on the main stem and tributaries of the Mekong River in Laos and Cambodia is likely to contribute significantly to declines in fish production and loss of biodiversity. Therefore, there is an urgent need to provide accurate predictions on the response of river fish populations to forecasted changes in river flow. In this study, 12 years of catch survey data from trawl boats (dais) located on the Tonle Sap River were used to investigate the effects of the flood pulse on fish production. An annual Flood Index was developed that takes account of flood duration, magnitude and the percentage of floodplain inundation in the Great Lake basin. A general linear model (GLM) was employed to test the ability of the Flood Index to explain seasonal variations in dai catch rates with month, lunar phase and dai location included as additional categorical explanatory variables. Correlations between the Flood Index and daily catch rates were positive and highly significant with the model explaining up to 66 % of the variation in Dai catch rates. The predictions emerging from the model suggest that reduced flooding will result in a proportional non-linear decline in fish yield with a reduction in the Flood Index. The findings therefore provide strong evidence to suggest that attenuated flooding downstream of impoundments will negatively impact fisheries in the TS-GL system and the Mekong River system as a whole.
Keywords: fisheries, flood pulse, tonle sap, cambodia, flow regulation, dams

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Protecting and Restoring Environmental Flows under the Florida Water Resources Act
Hamann R.

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Assessing climate change vulnerability of Botswana’s tourism sector in pursuit of an adaptation
Hambira W.L.

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The tourism sector in Botswana has grown to be the second largest economic sector as a result of the bid by the Botswana Government to diversify the economy in order to reduce overdependence on the mineral sector. The Okavango Delta, a unique wetland situated in the Ngamiland District, is currently the most favoured tourist attraction. However, climate variability poses a threat to many ecosystems upon which tourism is anchored including wetlands. Like all other relevant sectors in Botswana, the tourism sector will inevitably need to adapt to climate change hence the need to develop a suitable adaptation strategy to climate change. For this to be achieved, the extent to which the industry is vulnerable to climate change has to be determined and this is dependent upon the exposure of the industry to the direct and indirect impacts of climate change. Direct impacts include: a change in climate dependent tourism seasonal activities which could have a negative impact on the competitiveness of destinations and the profitability of tourism businesses. On the other hand the indirect impacts could be: environmental changes resulting in change in water availability, biodiversity loss, reduced landscape aesthetics, altered agricultural production (e.g. food and wine tourism), increased natural hazards, damage to infrastructure, increase in vector borne diseases etc..; mitigation policies meant to reduce GHG emissions may result in an increase in transport costs and may foster environmental attitudes that may lead tourists to change their travel patterns; societal changes may also indirectly affect tourism e.g. reduction of global GDP due to climate change may reduce wealth available to consumers for tourism and anticipated growth in tourism. The Okavango Delta is one of the most important tourist site in Botswana comprising of the following tourists attractions: the delta itself, the Tsodilo Hills world Heritage site, Moremi game Reserve, Gchwihaba caves, Maun Educational Park and Nhabe Museum. Ironically, even though the area is rich in tourism resources, Ngamiland district happens to be one of the poorest districts in Botswana. Without a proper climate change adaptation strategy in place, the aforementioned tourist attraction sites will remain exposed to impacts of climate change and this would be detrimental to the tourism industry and the communities whose livelihoods are dependent upon it. While an adaptation strategy does not reduce the threats, it will help reduce the vulnerability of those affected. This paper thus endeavous to screen for climate change vulnerability in Botswana’s Tourism industry with special reference to wetland based tourism. The methodology entails an assessment of vulnerability indicators such as trends in climate change variables such as precipitation and temperature; physical risks as may be shown by flood risks and share of land covered by forests; impending impacts of climate change on tourism resources such as biodiversity, water supply, infrastructure, regulatory and market aspects. A preliminary content analysis of existing sources of information pertaining to these attributes shows that Botswana’s tourism industry is indeed vulnerable to climate change and hence a suitable adaptation strategy needs to be developed. This is essential for sustainable tourism and community livelihoods.
Keywords: tourism, climate change, vulnerability assessment, adaptation

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Floods, fishery and fish populations in the Zambezi and Kavango Rivers
Hay C.J., van der Waal B.C.W., Klingelhoeffer E., Naesje T., Thorstad E.

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Annual surveys with standardized fleets of gillnets undertaken for periods of 12 and 10 years at fixed stations in the Kavango River and Zambezi, Chobe and Kwando Rivers in Namibia were analysed as part of a fish life monitoring programme by the Namibian Ministry of Fisheries and Marine Resources. The fleet of gillnets used consisted of 11 panels with mesh size increments from 12 mm to 150 mm, ensuring coverage of all larger fish sizes. A similar fish community structure was found in both rivers with the fish community dominated by medium sized fish species such as Brycinus lateralis, Schilbe intermedius, Marcusenius altisambezi and Hydrocynus vittatus, all species adapted to utilize the floodplains. The larger and economically important species were however far more common in those areas where the fish were protected from netting activities in both the Kavango and the Kwando rivers. At those stations where long-term gillnetting had taken place, the fish community structure was depressed for larger fish sizes that are harvested commercially 75 to 120 mm mesh nets. In the conservation area in the Kavango River [ Mahango Game Reserve, now part of the Bwabwata National Park] and the Kwando [Mudumu National Park in Caprivi] the recorded catches were generally double and especially so for the larger cichlids than in those areas where fishing occurred. The results indicate that the fishery impact varied, with some species absorbing impacts while others appear more sensitive to fishery pressure. Examples of species that experienced negative impacts from the fishery were the two cichlids, Oreochromis andersonii and Oreochromis macrochir but Hydrocynus vittatus, Serranochromis macrocephalus and Schilbe intermedius seemed to be less affected. The year-to-year changes in experimental gillnet catch per unit effort values indicate that the average peak level of the annual flood plays an important role in fish production as does the highest peak level in a particular flood cycle. An index of flooding was created, based on average water level above 2 metres, and the number of days the water was higher than 2 metres. The fish were divided into three groups according to the mesh sizes in which they were caught - small mesh sizes 22 to 35 mm, medium mesh sizes 45 to 73 mm and the large mesh sizes 93 to 150 mm. The small and medium size fish species seem to react to the flood of that year whereas the large species reacted positively [when the flood was high] or negatively [low floods] to the flood cycle two years prior to the survey dates. Fish production may be influenced by the flood cycle from more than one specific year. A combination of two years or even more may culminate in the effect the flood cycle has on fish production. Fish species and communities in highly pulsed systems naturally respond to the unpredictability of the flood regime. They compensate for the variability by having short trophic pathways, lateral and longitudinal migratory behaviour, colonizing abilities, short life cycles, seasonal spawning with a high fecundity and no parental care. These species are also r-selected and growth to maturity within 1-2 years. The natural mortality is variable, the biomass is low, but the productivity is high. Furthermore, the species are very resilient, with a high potential yield. These species could be used as a basis for a fishery. At present the fishery and prescriptive regulations are directed at the larger but slower growing cichlid species that seem to be much more vulnerable to fishing pressure as experienced in the study. Recommendations on directing fisheries on the short-lived floodplain species are proposed to counter the present depletion of especially cichlid populations by commercial fishing, affecting the long-term sustainable tourist angling attraction of the region.
Keywords: floodplain fisheries, fish production, flood peak levels, Kavango River, Zambezi River

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The effects of flood pulses on organic carbon storage and peat accumulation in the seasonal floodplains of the Okavango Delta, Botswana
Heinl M., Rutz D., Murray-Hudson M., Sliva J.

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The accumulation of organic matter in soils in tropical environments with a prominent dry and hot season is basically limited to permanently or regularly flooded areas along river courses. The accumulation process is dependent on the duration of anaerobic conditions in the soil profile caused by the flood. In Botswana, the high dynamic of the flood pulses in the floodplains of the Okavango Delta creates a huge variety of site conditions with different flood durations and frequencies resulting in a diverse and small-scale pattern of accumulated organic matter. The study carried out in 2004 specifically investigated the effects of flood duration, flood frequency and time-since-last-flood on organic carbon sequestration in form of soil organic matter (SOM) in the floodplains of the Okavango Delta. The study area covered the seasonal swamps between the southern end of Chief’s Island and the veterinary fence in the south of the Okavango Delta (S 19°42; E 23°20). The flood history of the study area was reconstructed by analyzing a series of 98 LANDSAT satellite images of from 1989 to 2003 (15 years). Three hundred and fourteen plots were sampled at random across floodplains. At each plot, a 30 cm deep soil profile was taken and the depth of the soil profile with high organic matter content was measured. A soil sample of the upper 10 cm layer (A1 horizon) was taken for analysing the weight percentage of soil organic matter (SOM) content. The absolute values of SOM in the investigated plots ranged from 0.7% to 30.3%. The mean value (4.4%) and the median (2.7%) are relatively low compared to the large amplitude of 29.6%. Soil organic matter correlated significantly with flood-frequency (0.708***), flood-duration (0.684***) and time-since-last-flood (-0.681***). The organic carbon accumulates in soils where flooding is frequent and of long duration, but the storage depletes fast when the regular flood ceases. Peat accumulation (>30% SOM) was only observed on sites flooded every year. Using the derived relations between flood frequency and SOM, the total amount and the spatial distribution of the soil organic matter could be estimated for the study area in the Okavango Delta. The knowledge gained about the accumulated SOM in the Okavango Delta floodplains and the effect of the flood attributes allows modelling of soil organic carbon sequestration under various flood scenarios.
Keywords: soil organic matter, floodplains, carbon sequestration, Okavango

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Multi-scale Mapping of Wetland Inundation and Vegetation in the Central Amazon with ALOS PALSAR
Hess L., Durieux L., Novo E.M.L.M., Silva T., Arraut E., Affonso A., Marshall B., Chapman B.

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Freshwater ecosystems cover less than 1% of Earth’s surface, but are estimated to support about 5% of all described species, with freshwater fish alone accounting for about 20% of all living vertebrate species. At the same time, freshwater habitats are among the least well characterized in terms of biodiversity, and among the most threatened by a wide range of human activities. Systematic conservation planning is required in order to protect the biodiversity of Amazonian freshwater ecosystems and to promote sustainable resource use, and may be based on biodiversity surrogates rather than direct species counts. Numerous ecological studies have concluded that inundation periodicity and water properties are the most important factors structuring biological communities of Amazonian wetlands, and remote sensing studies have shown that L-band synthetic aperture radar (SAR) sensors such as ALOS PALSAR are ideally suited to mapping inundation state and vegetation structure of flood-pulsed wetland habitats. Using data sets provided through the ALOS Kyoto & Carbon Initiative of the Japan Aerospace Exploration Agency, maps of wetland habitats and inundation dynamics were generated at two spatial scales using PALSAR Fine Beam mode (25 m; 2-4 coverages per year) for focus sites and ScanSAR mode (100 m; 8 coverages per year) for a º6 x 6º area of the central Amazon in Brazil. Vegetation structure and flooding state on each date are derived by multi-resolution segmentation followed by classification based primarily on multi-date backscatter of image objects. Results for a prototype 6º x 6º area of the central Amazon demonstrate the ability to distinguish among floodplain forest communities with varying inundation periodicities and to characterize regional variability in the timing of flood pulses. Merging of SAR-based products with maps of water properties created using Landsat Thematic Mapper allows discrimination of communities inundated primarily by white water or black water. This information provides an important input for systematic conservation planning.
Keywords: ALOS PALSAR, Amazon, inundation, floodplain, wetlands, habitats

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Influence of Altered River Hydrology and Nutrient Loadings on Sustainability of Floating Freshwater Marsh in the Mississippi River Deltaic Plain, Louisiana, USA
Hester M., Fisher K.

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Managing the consequences of large floods in ephemeral rivers in Namibia
Heyns P.

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The Cuvelai Basin, located in southern Angola and northern Namibia, is a successive, transboundary, ephemeral watercourse s that is infrequently subject to very large floods during the rainy season. The Kuiseb Basin in Namibia is an ephemeral watercourse system, flowing westwards from about 40 kilometres west of the City of Windhoek in the Khomas Hochland highlands in central Namibia, through the Namib Desert, to the Atlantic Ocean. The river is infrequently subject to very large floods which can cause severe damage to the water supply infrastructure at the coast. The purpose of the paper is to examine the effect and consequences of the ephemeral pulses in the Cuvelai and the Kuiseb watercourses on economic development and to make recommendations about means to improve natural resource governance to mitigate the identified adverse impacts. The hydrology of the Cuvelai and the Kuiseb is typical of an arid climate. The runoff is generated by unpredictable and spatially unevenly distributed convective summer rainfall that often has a high intensity of short duration. The frequency of runoff events and the magnitude of the floods play an important role in the predictability of possible floods and the measures required to manage the expected inundation including damage to infrastructure, impacts on livelihoods and the general consequences of such events. The Cuvelai Basin supports the livelihood of more than half of the total population in Namibia. The basin has a very flat topography and a shallow gradient to the south. The patches of fertile land between the braided watercourses across floodplains and huge tracts of grassland make it possible for dry land crop farming and stock farming. When large floods occur, the ephemeral streams overflow and join each other, causing sheet flow across the floodplains. The flow is seldom in excess of 50cm in depth, but the mahango fields and houses t on low lying areas are flooded. This causes damage to crops and severe displacement of the population. The upper Kuiseb river basin has a steep gradient to the coast and cuts through the landscape. Near the coast, the lower Kuiseb flattens out and forms an ephemeral wetland. The river supports commercial stock farming in the upper reaches, a rural small stock farming community living along the lower Kuiseb, the port of Walvis Bay and other developments along the coast. Walvis Bay relies on water supplied from alluvial aquifers in the lower Kuiseb and the infrastructure that is used to abstract the water is subject to severe damage when large floods reach the lower reaches of the river. This results in severe water shortages which affects socio-economic activities and the quality of life of the local population. In both the Cuvelai and Kuiseb basins there is a need for good water governance to be in a position to deal effectively with the consequences of the major flood events. . The conclusion drawn from the analysis will lead to the proposal of recommendations for further consideration by the disaster management authorities.
Keywords: flood-pulsed ephemeral rivers, socio-economic effects of floods, response to floods

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Characterizing the dynamics of dissolved organic matter in the coastal wetlands of the Everglades, USA.
Jaffe R., Chen M., Yamashita Y., Maie N., Boyer J., Price R., Scinto L.

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Dissolved organic matter (DOM) dynamics in wetlands and estuaries are complex and often difficult to assess using traditional geochemical approaches. It has become clear that quantitative measurements (DOC) alone do not properly allow for assessing the multitude of sources (e.g. emergent and submerged vegetations, soil/sediments, groundwater, and rainwater) and the various diagenetic processes (e.g. photodegradation, biodegradation) that can alter the DOM characteristics in aquatic ecosystems. In this study, we incorporate bulk DOC measurement with several spectroscopic techniques, including UV-Vis and fluorescence to characterize the sources and distribution of DOM across the greater Everglades landscape. Specifically, Emission Excitation Matrices fluorescence (EEM) coupled with Parallel Factor Analysis (PARAFAC) were used successfully to understand the dynamics of DOM in the Everglades landscape ranging from the Water Conservation Areas, through Everglades National Park, to Florida Bay. Additionally, DOM in surface and groundwater, dominant vegetation leachates (including periphyton, seagrass, and senescent leaves of sawgrass, spikerush and mangroves) and soil leachates were characterized using EEM-PARAFAC and potential degradation processes were assessed through bio-and photo-degradation studies. Fluorescence based EEM-PARAFAC analyses revealed DOM compositional differences both on spatial and temporal (wet vs. dry season) scales. As such increased microbial source loadings in some estuarine areas and Florida Bay during the wet season and during high primary productivity were observed. A clear trend from soil dominated to microbially enhanced DOM sources was observed along a sampling grid ranging from the northern to the southern Everglades. Compositional differences between waters from the peat based Shark River Slough and the marl-based Taylor Slough as well as clear differences between surface and ground water DOM were also observed. Florida Bay could be subdivided into four distinct zones based on DOM composition, and seasonal variations were controlled by primary productivity patterns and hydrologically controlled discharge from the Everglades. For the Florida Keys region, DOM changes with distance from shore were observed as was the influence of Florida Bay waters in the Keys. Differences between surface waters DOM and that in groundwater from both the Everglades and Florida Bay were also observed applying EEM-PARAFAC. Photo- and bio-degradation of plant leachates readily showed that the combination of both processes was most effective in promoting DOM compositions similar to those in natural surface water of the Florida Coastal Everglades. The data generated in this study will make a significant contribution to a better understanding of subtropical wetland and estuarine DOM characterization and its environmental dynamics, biogeochemical carbon cycling processes, and potential relationships to environmental restoration and global climate change issues.
Keywords: Dissolved organic matter; fluorescence; Everglades

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Evolution of Science and Science Communication at Florida Coastal Everglades Long Term Ecological Research (FCE-LTER) Program
Jaffe R., Gaiser E., Rugge M., Ogden L., Heithaus M., Price R.

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Flooding tolerance of Brazilian Coastal Plain Forest (Restinga) trees: possible impacts of climate change.
Joly C.A., Oliveira V.C.

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The occurrence of flooding events is common in several Brazilian ecosystems. Their effect on physiological and morphological responses in plants is a consequence of a partial decline of O₂ concentration in the soil. Under this condition, the decrease in the rates of aerobic root respiration is detectable and hence ATP production is impaired and metabolism is disrupted. Among the main consequences of oxygen depletion on plants are a decrease in stomatal conductance and photosynthesis, changes in metabolite levels, plant hormonal imbalances, and deficient water and nutrient uptake with deleterious effects on plant growth and survival. However, some plants have acquired some characteristics to survive and grow under anaerobic conditions. The mechanisms of tolerance to flooding conditions are multiple and complex, including responses at all levels of organization from biochemical to anatomical and morphological alterations. The Atlantic coastal vegetation of Brazil is a mosaic involving all types forest and also the neighborhood open vegetation. Plant communities at the periphery of the Atlantic rainforest are subjected to adverse environmental conditions, such as flooding and lack of nutrients, particularly in the case of the Southeastern Brazilian Coastal Plain Forest, locally named Restinga Forest. In this area, the water table is above or close to the soil surface for most of the whole year. Besides, the vegetation received aerosol particles coming from ocean that difficult even more the plants development. Flooding conditions of Restinga Forest are different from that found in Central Amazonian Floodplain Forest, described as an aquatic-terrestrial transition zone where flooding is triggered by flood-pulse with a mean amplitude of about 10 m. Furthermore, the Amazonian Varzea, grows in a soil with high stocks of macro and micronutrients. In Restingas flooding occurs due to a very high average of rainfall during the summer coupled with pour soil drainage, a combination that results in a gradual elevation of the water table, which may reach soil surface in early December. Later in the summer, water may be up to one meter above soil level, totally submerging the root system and lower stem of trees, small plants and seedlings for, in average, not more than 1 month. Restinga solis are classified as Oxyaquic Quartzipsamments, essentially sandy, acid (pH 3,4 to 4,2), with extremely low contents of phosporus and nitrogen, SB (sum of exchangeable bases) between 1,5 and 4,2 mmolc kg-1, and with a high concentration of Aluminum. The present paper summarizes the available knowledge on flooding tolerance mechanism of Restinga trees, focusing on 9 species Tabebuia cassinoides (Lam.) DC (Bignoniaceae), Erythrina speciosa Andr. (Leguminosae-Papilionoideae), Calophyllum brasiliense Cambess. (Clusiaceae), Alchornea triplinervia (Spreng.) Müll. Arg. (Euphorbiaceae), Nectandra opositifolia Nees & Mart. Ex Ness (Lauraceae), Eugenia umbelliflora Berg (Myrtaceae), Gomidesia schaueriana Berg (Myrtaceae), Guapira opposite (Vell.) Reitz (Nyctaginaceae), and Guatteria gomeziana A. St. Hil. (Annonaceae). The results are discussed focusing on the possible consequences of climate change on “Restinga” trees and, as consequence, for the ecosystem as whole, threatening the livelihood of hundreds of families that live from this type of forest.
Keywords: climate change, coastal plain forests, flooding, Brazil, restinga

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The Status of Mires and Peatlands in Africa
Joosten H.

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Peatlands have a wide international significance and their wise use is crucial to the implementation of the United Nations Framework Convention on Climate Change (UNFCCC), the Ramsar Convention, the Convention on Biological Diversity (CBD), and other international instruments and agreements. Peatlands are globally important as carbon stores and sinks. They store more carbon than all forests of the world and constitute a global carbon pool of about 412 x 10¹⁵ g C as compared to about 694 x 10¹⁵ g in all global plant biomass, 1,600 x 10¹⁵ g in all soils (including peat), and >700 x 10¹⁵ g in the atmosphere (Gorham 1995). Currentlysequestering rate of C in global mires is estimated at 40-70 x 10¹² g y^-1. Peatlands contain 10 % of the global freshwater volume and are significant in maintaining freshwater quality and hydrological integrity. Peatlands furthermore play an important role in maintaining permafrost and preventing desertification. Peatlands support important biological diversity. They are the refugia of some of the rarest and most unusual species of wetland-dependent flora and fauna. Various mire types develop sophisticated self-regulation mechanisms over time and have an inherent tendency to develop complex surface patterning. This makes them outstanding examples of ecosystem biodiversity. With a peatland area of 130,000 km² and an estimated peat carbon volume of 10 Gigaton Africa belongs with Australia and Antarctica to the continents poorest in peat resources. The differences between African countries are, however, enormous with many countries possessing little by way of peat reserves and few countries possessing substantial peatlands. Similarly the diversity is large, with peatlands occurring from the high mountains to the coastal lowlands. The paper discusses the status of mires and peatlands in Africa, compares this with the situation in other continents, and formulates urgent priorities for peatland inventory and conservation.
Keywords: Africa, peatlands, mires

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Effects of climate change on nutrient (N, P) sorption in tidal riverine floodplain forests, Georgia, USA
Jun M.-H., Craft C.

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Twenty Years of the Flood Pulse Concept: State of the Art and Perspectives
Junk W.J.

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Clearing of woody plants for pastures in the Pantanal: sustainable management or environmental destruction?
Junk W.J., Nunes da Cunha C.

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Integrated Flow Assessment: promoting sustainable use of the Okavango River system
King J.M.

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A Technical Diagnostic Analysis (TDA) of the Okavango River Basin was recently completed for OKACOM, the river basin organisation owned by the riparian countries Angola, Namibia and Botswana. The TDA was funded by the UN-FAO via a project named Environmental Protection and Sustainable Management of the Okavango. One part of it was an Integrated Flow Assessment (IFA), co-funded by Biokavango, which used an holistic approach to provide predictions of the ecological, social and resource-economic implications of development of the basin’s water resources. Three scenarios were chosen by the governments, representing Low, Medium and High levels of possible interventions such as irrigation schemes and hydropower dams. The High Scenario was generally seen as not realistic and was mainly used to assess what it would take to push the ecosystem into significant degradation. With a major emphasis on capacity-building and basin-wide collaboration, a full multi-disciplinary team was appointed from each country and all worked in basin-wide discipline groups. The hydrologists set up a basin hydrological model that simulated current and future development-driven flows at points along the system. These daily simulated flows were converted to summary hydro statistics that showed in ecologically-relevant ways how the flow regime could change. Ecologists then predicted the ecological responses of the system and sociologists and resource economists translated these into impacts on subsistence users of the river. Outside of the IFA, macroeconomists estimated the expected economic gains from the developments. The project ran from July 2008 to October 2009, and involved 40 specialists as well as project managers and government representatives. Major findings were: 1. The Okavango is a flood-pulse driven system. Massive riverine floodplains, particularly in the Cuito River and the lower Okavango, store floodwaters upon which the lower part of the ecosystem and associated social structures depend. 2. Significant changes in the flow regime would occur with water-resource development. Dry-season flows, for instance, could begin up to 11 weeks earlier and last 18 weeks longer than present in different parts of the basin under the most extreme scenario. The flood season could shorten by two months or more and lose one-third of its volume, impacting the floodplains. 3. The flow changes would result in a progressive decline in condition of the river ecosystem from the Low to the High Scenario, with the High Scenario rendering large parts of the system unable to sustain present beneficial uses and causing significant terrestrialisation within the Delta. 4. Run-of-river abstractions could severely impact smaller headwater tributaries in the dry season, but the effects would be localised. An accumulation of such developments in the upper and middle reaches would trigger a widespread decline in the middle and lower reaches with increasing transboundary impacts. 5. Climate change is likely to provide more water for the upper basin but exacerbate drying of the Delta. Sustainable use of the river system could be promoted by adopting a new perspective on water-resource development. The scenarios could be used to identify the limit of socially-acceptable degradation of the ecosystem and impact on its users, and then ways devised of living and developing within that limit. It is the opposite of historical - and much of the present - practice whereby a need is identified and then development proceeds, and then another need and another development, and then another......
Keywords: EFlows, Integrated Basin Flow Assessment, sustainable use

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A chance to achieve truly sustainable development of the Okavango system
King J.M.

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Water-resource developments routinely target the surface-flow or groundwater regimes of rivers. Developing these water resources without unacceptable ecological and social impacts requires a major shift in perspective from the past, toward a basin-wide and holistic planning approach. Basin-wide planning recognises that water developments in one part of a river ecosystem can impact ecosystem functioning, other water-use sectors and human subsistence users of the river hundreds of kilometres downstream and across national boundaries. Holistic planning addresses the flow, sediment, chemical and thermal regimes of the whole river ecosystem, its aquatic and riparian plant and animal communities, the subsistence users of the system and the resource-economic implications of development at all levels from local to national/regional. Scenarios encompassing all these variables can illustrate the costs, in terms of ecosystem degradation and human impact, as well as the benefits, in terms of social uplifting and economic gain, for stakeholders and governments to consider. The concept of ‘Development Space’ uses the scenarios to help governments identify unacceptable levels of ecological and social impact, thereby defining an agreed limit to development. This is the opposite of historical practice whereby a need is identified and then development proceeds, and then another need and another development, and so on leading to conflict over water now so common globally. The Development Space, once defined, can be used in negotiations on each country’s entitlement. The outcome can form the basis of a Basin Development Plan against which individual projects can be assessed for compliance. This approach leaves each country free to develop its water resources in its own way within an agreed basin-wide plan. The Basin Development Plan can be periodically reviewed. The EPSMO Transboundary Diagnostic Analysis adopted the above approach in its preliminary Integrated Flow Assessment (IFA) to the point of production of the scenarios. Its final stages move beyond technical activities to be driven by political and social ones, and depend on the willingness of governments to aim for truly sustainable development.
Keywords: ecosystem approach, sustainable development, holistic basin-wide planning

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Restoring one of the most important wetland systems in the Murray-Darling Basin, the Macquarie Marshes – role of science, management and policy
Kingsford R.T., Ren S., Nairn L., Rayner T.S., Jenkins K.

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Managing the information overload for rivers– a WISE (Water Information System for the Environment) solution at the catchment scale
Kingsford R.T., McVicar S., House A., Ryall S.

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Okavango Delta dragonflies (Odonata) – distribution, habitat preferences and respond to changing environments
Kipping J.K.

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Human Cultural Adaptations to Flood Pulsed Wetlands
Kiviat E.

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Management or mis-management of African flood pulse fisheries
Kolding J., van Zwieten P.

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Impacts of vegetation blockages and the importance of floodplain flow pulse in the hydro-monitoring of the Okavango delta
Kurugundla C.N., Dikgola K.

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Impacts of the Biocontrol Weevil, Cyrtobagous salviniae on the decomposition of Kariba Weed, Salvinia molesta and Changes in Water Chemistry
Kurugundla C.N.

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Influence of hydrology on amphibian diversity and breeding behaviour in the Okavango Delta
le Roux M., du Preez L.H., Weldon C.

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Wetland oscillations, mire soil water and Hg accumulation in food chains, Norway
Lindholm M.

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The Wakkerstroom Mire: a Prospective Ramsar Wetland of International Importance in South Africa
Linstrom A.

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The Wakkestroom mire is a 700 ha wetland complex containing a variety of wetland habitat much of which is waterlogged for most of the season. It is hydrologically dependant on pulsing groundwater and stream inflow. The wetland is located in the upper catchment of the Tugela River and as such is subject to various land-use changes in a catchment subject to high intensity rainfall and high stream flow events. It is an important avifauna wetland as it contains the second largest number of breeding pairs of Crowned Cranes of any wetland in South Africa and 7 pairs of Whitewinged Flufftail. South Africa was one of the first signatories of the Ramsar Convention, an environmental treaty originally focusing on avifauna and aquatic habitats. One of the best known aspects of the Ramsar Convention is the List of Wetlands of International Importance, and it is the responsibility of authorities of the host country to manage and protect the designated wetlands in such a way that their natural capital will be retained for future generations. The Wakkerstroom wetland complex fulfills several of the Ramsar requirements as a Wetland of International Importance. Local communities depend in various ways on wetlands: from direct resource uses such as grazing and water abstraction to indirect uses such as tourism. The placement of the hamlet of Wakkerstoom on the Eastern Shore of the wetland allows for easy access to this largely intact wetland. This greatly facilitates the use of this wetland as a birding venue and as an open-air environmental education facility. This is supported by BirdLife South Africa’s development of a guide training facility (eco-tourism) on the western shore of the Wakkerstroom Wetland. These are important factors that increase the socio-economic value of this wetland, but which could also increase friction with direct users of the wetland. The conservation management implications and socio-economic benefits in the quest towards Ramsar recognition are investigated and reported on in this paper.
Keywords: Wakkerstroom, Mire, Ramsar, Benefits

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Quantifying hydrological impacts on diatom diversity in the Okavango Delta, Botswana.
Mackay A.W., Davidson T., Huntsman-Mapila P., Mazebedi R., Todd M.C., Wolski P., Woodward S.

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As highlighted by the Convention on Biological Diversity, inland water ecosystems are amongst the most threatened on our planet. The Okavango Delta is no exception, supporting a population of 125,000 in a semi-arid region where water resources are seasonally scarce for humans and other organisms alike. Future threats to the Okavango Delta, both natural (e.g. climate) and anthropogenic (e.g. pollution; abstraction; habitat degradation) are real. Diatoms (unicellular siliceous algae) are extensively used to monitor wetland integrity due to their ecological sensitivity to hydrochemical parameters. In this talk we will present results of the first ever, systematic study of diatoms in the Okavango Delta. Given the flood pulse nature of the Delta, together with low human impact, diatoms would not make good indicators of biological integrity. However, we do show that they are sensitive to changes in water chemistry and water-level regime, and therefore would make a powerful indicator with which to monitor future threats. Epiphytic diatoms were sampled from submerged stems of dominant macrophyte species characterising c. 100 sites. Plant selection was partly determined by the habitat being sampled. For example, in habitats with marginal vegetation, only edge plants from emergent species were selected. In the laboratory, permanent diatom slides were prepared according to standard techniques. Diatoms were counted using oil immersion phase contrast light microscopy at x1000 magnification, with at least 350-400 valves counted for each sample. Potential explanatory variables accounting for variation in diatom composition across the Delta were also collated for each site, including pH, conductivity, dissolved oxygen, velocity, water depth, and water level regime. Water chemistry variables were further analysed from a subset of 54 sites. Over 180 diatom species were identified in the Delta from 47 genera. Over 150 of these species have been identified in the Delta for the first time. Floristic analyses shows that in general the diatoms are indicative of low-alkalinity waters. Many species are global, some are African, and a few are very rare, and more work needs to be done to determine if any are endemic. Some common species found are very tolerant to elevated levels of nutrient enrichment. However, in the Delta their presence is not indicative of eutrophication, but is linked to energy flows and nutrient release from inundated floodplains. Using multiple regression techniques such as redundancy analysis, six explanatory variables were shown to significantly influence diatom distribution in the Delta. These mainly included cation composition of the waters, hydroperiod and flood. We were able determine which species grow best in locations with e.g. high and low hydroperiod. Using this information we can predict what will happen to certain species should hydroperiod in the Delta decline due to climate change or abstraction. For example, if hydroperiod does decline then species indicative of elevated nutrients in the Delta will increase.
Keywords: Okavango, diatom, diversity

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A framework for assessing ecological and economic tradeoffs of wetland tourism on local communities
MacLeod N.D., McIvor J.G., Martin T.G.

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Wetlands, such as the Okavango Delta and Kakadu National Park, are well recognised biodiversity treasure troves. Other wetlands with less international recognition also contain rich assemblages of species including many rare and threatened ones. These natural assets are underpinning a global growth in eco-tourism (and general tourism) worth substantial sums to national and regional economies. However, there are usually significant tradeoffs involved in expanding tourist developments centred on wetland resources and maintaining the ecological integrity of the same resources. There are also often tradeoffs between commercial and national interests in tourism-based development and the interests of local communities who are dependent on access to these resources for sustaining their livelihoods with little formal exchange between the competing sets of interests. Net gains to national economies may well come at the price of lost equity to local communities for whom the development may mean displacement or diminished equity. The paper presents a framework for identifying the nature and prospective magnitude of such tradeoffs employing a mix of economic simulation modelling and an ecological scorecard system based on a detailed set of ecological indicators. Economic impacts of a given management or development option are enumerated through the simulation models and the output offered in terms of choice sets whose elements also include the resulting ecological score card values. A rational process is suggested by which stakeholders can alter various development options and determine whether the iterative results represent an improvement or a deterioration of their position. This approach, while still under development is argued to offer a more transparent choice between potential economic and ecological outcomes than many alternative economic attempts to place pseudo market values on ecological attributes and determine the value of choices in net benefit terms. These largely mask the very tradeoffs that are of interest to equitable and sustainable development.
Keywords: tradeoffs, economics ecology, wetlands

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Fish Diversity in the Cahora Bassa Reservoir Some Twenty Five Years after the Dam Closure: Have there been an effect of the Change from the Lotic to Lentic scenario on the Zambezi River?
Mafuca J.M., Bills R.

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Assessing the impact of the Tubu Adaptive Joint Management System
Magole L.I., Moleele N.M., Ngwenya B.N.

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The impact of the National Agricultural Development Policy on the range in the flood pulse environment of Lake Ngami
Magole L., Mfundisi K., Fynn R.

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Lake Ngami has played an important part in the subsistence economy of the people living around it. Shaw, (1985) showed that in the 1980s the Lake supported an abundance of birdlife, fish and more than 30 000 cattle. He argued that livelihood activities based on these resources were dependent on the presence of water in the lakebed. The volume of water flowing down through the Okavango River Basin System into the Okavango River and finally into Lake Ngami in the extreme south west of the river system is dependent on both the level of precipitation in the river basin in the highlands of Anglola and local precipitation. Recurrent drought and low levels of precipitation in both these areas have resulted in alternate wet-dry periods for the Lake. Communities living around the lake have always responded by temporarily or permanently altering their livelihoods and land use patterns according to an informal and flexible land and water resources management strategy. However Government has since the mid 1970s introduced formal land and water management policies which advocate privatization and fencing of part of communal land throughout the country. This paper will critically appraise the government ranching and fencing policy as presented by the National Agricultural Development Policy (NADP) for its suitability to manage resources in the Lake Ngami flood pulse environment. A stakeholder and institutional analysis, policy provisions analysis, results of a range assessment of the lake area will be presented. Furthermore the paper will show the results of a mapping exercise to show the changes in the extent of grazing areas overtime. The result show the immediate effect of the policy has been to reduce the grazing area available for the community and disrupted traditional transhumance livestock management. Traditionally the community moved the cattle out towards the central Kalahari for the summer (wet-season resource) and then brought them back to Lake Ngami for the winter (dry-season resource). This movement between outlying woodlands for the wet season and floodplains for the dry season is typical of wildlife movement patterns in this area and in Africa in general and is based on sound ecological principals. The NADP took a large proportion of their wet-season resource constricting the livestock to the dry-season resource all year round resulting in a loss of the ability of livestock to graze in optimal seasonal resources as well as a loss of seasonal resting of the rangeland. This is likely to have reduced livestock production and appears to have altered the robustness of the range to recover from the dry season and droughts. Furthermore it has been found that the NADP lacks the flexibility and institutional integration necessary to manage water resources in semi-arid and flood pulse environments where weather systems are volatile and rainfall is unreliable.
Keywords: Land management policy, Lake Ngami, flood pulse, community livelihoods

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An Assessment of Botswana’s Institutional Capacity to Integrate Poverty and the Environment in National Planning Processes: Implications for Flood Pulse Scenarios
Makepe P., Tlotlego N.

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A scientific rationale underpinning recovery of the Tigris-Euphrates flood pulse - from ecosystem services to transboundary management
Maltby E

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The Tigris and Euphrates comprise a complex hydrological system which historically has delivered the pulses of floodwater essential for the maintenance of the Mesopotamian marshes. The hydrological system is also an international river basin encompassing four neighbourly states: Turkey, Syria, Iraq and Iran together with a negligible fraction of the catchment area in Saudi Arabia. The position of the marshlands at the lower end of the catchment makes them particularly vulnerable to the effects of changes upstream and also confers particular importance as a link and buffer between the basin and the coastal zone. Natural flood pulse dynamics provided for habitat diversity supporting rare and endemic species significant regionally and internationally. The historic marshlands were important for fisheries, including species vital to the Gulf marine economy and supported the development of a unique human community and culture of the marsh arab (Madan). Several studies have tracked the rapid rate of loss of the marshland due to engineering works within and outside Iraq. There has been significant recovery of the marshes since regime change in Iraq, but now there is renewed uncertainty over the future of the marshes because of competing demands for water elsewhere in the catchment and the possible effects of climate change manifest in periods of unpredictable and often extreme drought. The rationale for restoration and maintenance of the marshes is examined from a functional standpoint linked to the provision of different ecosystem services at local, national, regional and international scales. The significance of the flood pulse is exemplified in the rewetting response of desiccated soils and the possible consequences for water quality. A case for more informed transboundary management of the river basin is based on the benefits that can be derived for human well being, including environmental quality, economic welfare, culture and security.
Keywords: Mesopotamian marshes, Iraq, Ecosystem Services, Transboundary management

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Influence of intermittent feeding regime on water purification and greenhouse gas emissions from constructed wetlands for wastewater treatment: An overview
Mander Ü, Karabelnik K

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Pulsing hydrology is a common phenomenon in coastal zones (especially in estuaries and tidal marshes) and floodplains. Intermittent feeding that mimics the pulsing hydrology of natural wetlands is widely used in constructed wetlands (CW). In our study we analysed the results of 152 papers on the effects of intermittent loading on nutrient and organic material removal and greenhouse gas (GHG) emissions in CWs, indexed by the ISI Web of Knowledge. Combinations of the terms "wetland(s)", "intermittent", "pulsing", "nitrogen", "phosphor(o)us", "methane", and "nitrous oxide" occurring in titles, abstracts, and key words were used. In addition, we used data from our earlier studies on wastewater treatment efficiency of a batch-operating system and GHG emission from two hybrid CWs. In created riverine wetlands, pulsing effects enhance sedimentation, nutrient removal and decrease emissions of methane (CH₄) and nitrous oxide (N₂O). In terms of CWs for municipal, farming, and industrial/mining wastewater treatment, intermittent loading is mainly used in vertical flow subsurface flow (VSSF) filters to increase oxygen consumption. Some VSSFs operate as tidal flow systems. Likewise, batch-operated CWs, reciprocating wetland systems, and horizontal subsurface flow (HSSF) filters with pulsing water levels provide elevated oxygen supply for the mineralization of organic material and nitrification. Several studies on wastewater treatment CWs demonstrate that intermittent loading increases organic material mineralization, nitrogen and phosphorus removal, and the retention/transformation of various hazardous compounds. Little is known about the effects of intermittent loading in CWs on the fluxes of CO₂, CH₄ and N₂O in CWs for wastewater treatment. Our earlier results show that CH₄ emission was significantly lower from intermittently fed VSSFs than from HSSFs with stable water level, whereas N₂O and CO₂ emission was slightly higher from VSSF systems. Higher N₂O and CO₂ release from intermittent VSSF beds is contradictory to the results from studies on created riverine wetlands with pulsing hydrologic regime, but coincides with the results from paddy fields with inter-season drainage. It appears that pulsing (feeding) frequency controls the emission of N₂O, although further investigations should be conducted to achieve a better understanding of pulsing effects on GHG emissions from CWs.
Keywords: Carbon dioxide; Horizontal subsurface flow filter; Methane; Nitrous oxide; Vertical subsurface flow filter

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Increased organic carbon runoff in Estonian rivers in 1992-2007 as affected by changes in drought regime
Mander Ü, Pärn J

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Tourism development and sustainable livelihoods: the impacts of Lesotho Highland Water Project
Manwa H.A.

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The Lesotho Highland Water project is a water project signed between the Kingdom of Lesotho and the Republic of South African in 1986 to supply water to the Gauteng province of South Africa. The project had a number of objectives including the development of tourism, fisheries and other projects for social and economic development. Already, the government of Lesotho has realised substantial benefits from the project. It is estimated that the project contributes 14 per cent of government revenue, 25 per cent of Lesotho's total annual export revenue, and 5 per cent of GDP. There is, however, dearth of literature on tourism development in Lesotho in general and the contribution of the project in particular. This study had the following objectives: 1. To establish the extent to which communities around the LHW project are aware of tourism, and 2. To understand communities’ perceptions of the LHW projects contribution to tourism development and its impacts environmental and socio-economic impacts. The study used both desk research and primary data. The desk research involved a review of existing literature on the environmental and social impacts of the Lesotho Highland Water project on local communities. Primary data was collected through in-depth interviews with households of three villages around Katse dam (Halejone, Khohlonts’o and Hasoai) and Hamotloheloa, a village where some of the villagers who were displaced by the construction of Katse dam were resettled. The study used the sustainable development framework, to understand and interpret communities’ perceptions of tourism development in the Lesotho Highland water Scheme and its impacts on their livelihoods. The results indicated that the Lesotho Highland project has changed the livelihoods of the mountain people. Lesotho is still perceived as an add-on destination to tourists visiting South Africa. Using Butler’s model, Lesotho fits the exploration stage of tourism development. This is characterised by ignorance among the community on what tourism entails. There is also lack of investments in infrastructure by both the public and the private sectors. A lot of training and development would have to take place before the Lesotho Highland Water Project can reach its stated objective of sustainable tourism development that benefits the local communities.
Keywords: Sustainable livelihoods, Lesotho tourism, Lesotho highland water project

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Cultural Activities and Tourism: The Case of Khwai Village in the Okavango Delta, Botswana
Maokanyane G., Mbaiwa J.

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Phytoplankton biomass and biodiversity in the Okavango Delta
Marazzi L., Mackay A.W., Ramberg L.

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Dependence of pH, Electrical Conductivity, Dissolved Oxygen, Turbidity and Dissolved Organic Carbon on Flow for the Okavango Delta's Panhandle
Masamba W.R.L.

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Sanitation in and around the Okavango Delta, Botswana: Possible Future Consequences
Masamba W.

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Tourism and Livelihoods: The case of Khwai River Lodge and Khwai Village in the Okavango Delta, Botswana
Matlola M.L, Mbaiwa J.

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Assessing impacts of water-level regime on aquatic macroinvertebrates in the Okavango Delta
Mazebedi R., Mackay A.W., Davidson T., Wolski P.

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Aquatic macroinvertebrate diversity and community compositions are known to vary both spatially and temporally in response to several environmental factors. Effective conservation of macroinvertebrates in the Okavango Delta requires an in-depth understanding of their spatio-temporal variations and factors driving these variations. In wetland systems hydroperiod (duration and quantity of surface water on a wetland) is one of the major factors governing aquatic macroinvertebrate community structure, diversity and abundance. The hydroperiod in the Okavango Delta is controlled by the seasonal flooding regime and to a lesser extent by local precipitation. Hydroperiod gradients within the Okavango Delta are important for maintaining high vegetation-habitat diversity. Aquatic macroinvertebrates were collected from over 100 sites in six areas spanning several hydrological gradients in the Okavango Delta. The main criteria for the selection of sites was to maximise the diversity of organisms collected with respect to flooding frequency, hydroperiod and habitats across the Okavango Delta. At each site, sampling of assemblages was done on at least three vegetation types for exactly two minutes using a scoop net. Habitats characterized include marginal vegetation (MV) in channels, lagoons and backwaters, inundated floodplains, floating vegetation, submerged vegetation and seasonally flooded pools. A total of 62 aquatic macroinvertebrate taxa were identified from this study. Our results indicate that major significant drivers of aquatic macroinvertebrate variability in the Okavango Delta include hydroperiod, seasonal flooding regime and habitat variability. Macroinvertebrate diversity within the Delta tends to be high in sites with a relatively short hydroperiod, in seasonally inundated habitats especially floodplains and during high water conditions. Since diversity of aquatic macroinvertebrates is highest during high floods and on seasonal flood plains, any hydrological developments that may compromise the flooding extent of the Okavango Delta system will impact on the diversity of aquatic macroinvertebrates and hence on the general diversity of the Okavango Delta.
Keywords: aquatic macroinvertebrates, hydroperiod, Okavango, biodiversity

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Towards elimination of malaria: understanding the role of the Delta wetlands
Mazhani L., Masendu R., Chihanga S., Mokone G.G., Fadlelmola F.M., Quaye I.K.

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Malaria in Botswana is seasonal with most of the transmission occurring between November and April of the following year during the rainy season. Although the country profile is designated as epidemic for malaria, parts of the Ngami and Okavango Delta are endemic. This is primarily attributed to persistent swamps within the Delta area that provide breeding sites for vectors. Data available to date is limited in details of specific relationships between flood pulsing and vector populations, relation to human activities, climate change that impact on swamp persistence and ultimately malaria transmission. The recently adopted country strategy is toward malaria elimination, due to an overall decline (4.2% in 2000 to 1% in 2008) in malaria transmission. This strategy requires that baseline data on epidemic and endemic zones be carefully collected, in addition to understanding the population dynamics of the sole vector responsible for transmission, the Anopheles arabiensis. The Delta area which contributes to 20% of transmission in the north is an important component of the data acquisition process. The project will be a prospective assessment of the currently stratified zones within the Delta region for malaria transmission to establish the true transmission profile by serological methods. In parallel with the serology, programs to educate the population to validate data on the use of insecticide treated nets (ITNs), effectiveness of indoor residual spraying (IRS) and case reporting shall run concurrently. Seasonal variations in vector population densities shall be related to transmission intensity using odour-baited light traps, pyrethrum spray collections and pit shelters. Survey locations shall be mapped using Remote Sensing and Geographical Position System (GPS)/Geographical information System (GIS). In addition, the recommended case management of RDT, microscopy and proposed radical treatment with Artemisinin Combination Therapy (ACT +primaquine) shall be assessed for compliance in clinical settings. Whether or not the instituted interventions are impacting the wetlands as an ecological system will also be studied It is expected that at the end of the multipronged study, a new stratification of the Delta region with respect to malaria transmission intensity shall be accomplished. The persistence of swamps in the Delta in relation to flood pulsing and its impact on vector populations shall also be established. It is expected that the communities will be better sensitized to contribute meaningfully in reducing swamps, human vector contact and prompt case reporting to the clinics. Whether or not the main vector species in the transmission is Anopheles arabiensis as is currently known will also be confirmed.
Keywords: Malaria elimination; Transmission; Okavango Delta; Flood pulsed; ITNS; IRS,

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The nature and causes of the variability of Boteti River flows, Botswana
Mazvimavi D.

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Poverty and Sustainable Tourism in the Okavango Delta, Botswana
Mbaiwa J.

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Assessing the impact of climate change on tourism activities and their economic benefits in the Okavango Delta
Mbaiwa J., Mmopelwa G.

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What does community participation really mean? CBNRM, luxury ecotourism and the future of community partnerships
Mbaiwa J., Duffy R.

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The value of the Bahi wetland, Tanzania, and threats to its ecological character
McCartney M.P., Rebelo L-M.

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A major constraint to the sustainable management of African wetlands is lack of knowledge by government planners, natural resource managers and local communities of the diverse benefits that they provide and the anthropogenic threats to their ecological character. The Bahi wetland is a shallow ephemeral lake, located in central Tanzania. With an irregular cycle of flooding and drying, the spatial extent of the lake varies considerably from year to year. The wetland supports a high level of biodiversity. It has been identified as one of the most important wetlands in Tanzania for water birds and meets the Ramsar 1% criteria for nomination. The wetland is of vital importance to the communities that live in the area, supporting a range of livelihood activities including cultivation, fisheries, livestock grazing, salt production and the harvesting of natural products. As population rises, initiatives to increase food security and generate cash-income are multiplying, increasingly putting the wetland under pressure. Environmental degradation is increasing. Uranium deposits have been found in the wetland and mining possibilities are currently being evaluated. In recent years, development programs have assisted in the establishment of many small-scale rice irrigation schemes which divert water from the inflowing rivers. In this paper we report a multi-disciplinary study, comprising hydrological, remote sensing and livelihood investigations, conducted to provide baseline information on the wetland, its functioning and its value to local communities. Although current irrigation diversions are estimated to represent only a relatively small proportion (<10%) of the mean annual flow into the wetland, in dry years they could abstract a much greater proportion (ca. 60%). Uranium extraction and possible future irrigation development, coupled with the impacts of climate change, pose threats to the ecological integrity of the wetland as well as the livelihoods of many of the people who depend on it. Future planning and management of the wetland needs to take into account the diverse benefits it provides and the interests of all stakeholders.
Keywords: ephemeral lake, irrigation, livelihoods, Tanzania

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Comparing life history traits and adaptations to life in an ephemeral saline lake, the Makgadikgadi Salt Pans
McCulloch G.

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Unpredictable flood regimes among ephemeral saline lakes contribute high variability not only to their physical and hydrological character, but also to their suitability as habitat for the many species of flora and fauna that depend on them. Life history traits among species that live in these temporary aquatic systems are often tied to the ‘boom or bust’ nature of their habitat, and have given rise to some extraordinary adaptations. The Makgadikgadi depression in northern Botswana comprises one of the largest ephemeral saline wetlands in the world and is home to the most important breeding sites for Greater Flamingo (Phoenicopterus ruber roseus) and Lesser Flamingo (Phoeniconaias minor) in Africa. This paper presents the results of a long-term study on the breeding success of flamingos at Sua Pan, which forms the lower part of the Makgadikgadi depression. Food availability and breeding success is highly dependant on the occurrence and extent of seasonal flooding on Sua Pan, which corresponds to highly variable annual rainfall. Breeding success occurred only during years of good rainfall and subsequent flooding. During low rainfall years, the pan often dried out before flamingo breeding was complete, forcing birds to abandon their eggs and chicks and seek feeding grounds elsewhere. The breeding strategies of Greater and Lesser Flamingo, however, appeared to be different. Greater Flamingos predominantly nested on small islands during good rainfall years when these islands were protected by extensive flooding. Lesser Flamingos, on the other hand, nested very early in the rainy season each year, suggesting a strategy that attempts to improve the likelihood of raising a chick before the pan dried up. The population viability of these long-lived species is also discussed, suggesting cyclical population fluctuations correlating to climatic patterns and indicating a corresponding sensitivity to climate change. Migration and a highly nomadic lifestyle is presented as one of the most important adaptations in the life history of both flamingo species, highlighting the importance of a network habitat of many ephemeral wetlands in their population viability.
Keywords: ephemeral, flamingos, breeding adaptations, boom or bust, Makgadikgadi

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Global monitoring of wetlands extent and dynamics: An Earth System Data Record of Inundated Wetlands
McDonald K.C., Chapman B., Podest E., Schroeder R., Willacy K., Hess L., Whitcomb J., Moghaddam M., Kimball J.S.

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Wetlands exert major impacts on global biogeochemistry, hydrology, and biological diversity. The extent and seasonal, interannual, and decadal variation of inundated wetland area play key roles in ecosystem dynamics. Wetlands contribute approximately one fourth of the total methane annually emitted to the atmosphere and are identified as the primary contributor to interannual variations in the growth rate of atmospheric methane concentrations. Climate change is projected to have a pronounced effect on global wetlands through alterations in hydrologic regimes, with some changes already evident. Despite the importance of these environments in the global cycling of carbon and water and to current and future climate, the extent and dynamics of global wetlands remain poorly characterized and modeled, primarily because of the scarcity of suitable regional-to-global remote sensing data for characterizing their distribution and dynamics. As part of a NASA Earth Science project, we are constructing a global-scale Earth Science Data Record (ESDR) of inundated wetlands to facilitate investigations on their role in climate, biogeochemistry, hydrology, and biodiversity.

The ESDR is comprised of two complementary components: (1) Fine-resolution (100 meter) maps of wetland extent, vegetation type, and seasonal inundation dynamics for continental-scale areas covering crucial wetland regions, and (2) global monthly inundation mappings at ~25 km resolution for the period 1992-2009. The fine-resolution ESDR component is constructed from synthetic aperture radar (SAR) data from the Phased Array L-Band SAR (PALSAR) instrument on-board the Japanese Space Agency (JAXA) Advanced Land Observing Satellite (ALOS). The wetlands classification algorithms are based on an object-oriented image segmentation approach and a statistically based decision tree classifier, following from the prior work with the Japanese Earth Resources (JERS) SAR previously developed and tested for mapping of tropical and boreal wetlands.

The global monthly mappings of inundation area at the 25km scale are derived from remote sensing observations from multiple satellite sources, focusing on active/passive microwave SeaWinds-on-QuikSCAT and AMSR-E data for 2002 onward and ERS scatterometer and SSM/I for retrospective years (~1992 onward). The use of MODIS and AVHRR NDVI and/or LAI is under evaluation. We employ the 100-meter SAR-based mappings to validate and quantify the accuracy of the coarse resolution inundation maps to ensure consistency within the ESDR products.

We present details of ESDR construction including data sets employed, algorithm application, cross-product harmonization, and planned data set distribution. This ESDR will provide the first accurate, consistent and comprehensive global-scale data set of wetland inundation and vegetation, including continental-scale multi-temporal and multi-year monthly inundation dynamics at varying scales.

Keywords: Remote sensing, wetlands, inundation

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NASA’s Soil Moisture Active/Passive (SMAP) Mission: Monitoring hydrodynamic ecosystems with satellite microwave remote sensing
McDonald K. C. , Podest E., Njoku E., Entekhabi D., O'Neill P.

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Satellite active and passive microwave remote sensing can be applied to characterize soil moisture and land surface inundation dynamics. NASA’s Soil Moisture Active/Passive (SMAP) mission, now under development and currently planned for launch in 2014, will use a combined radiometer and high-resolution radar to measure surface soil moisture and freeze/thaw state globally providing new opportunities for scientific advances and societal benefits. SMAP will offer a new capability for characterizing and monitoring inundated wetlands through combined high spatial and temporal resolution datasets. Major science objectives of SMAP support the understanding of processes linking terrestrial water, energy and carbon cycles, the quantification of net carbon flux, and the extension of capabilities for weather and climate prediction models. Soil moisture is a key control on evaporation and transpiration at the land-atmosphere boundary. The amount of surface moisture and its status define a surface hydrospheric state that is key to linking terrestrial water and carbon cycles and a key determinant of the terrestrial carbon cycle.

The SMAP instrument package incorporates an L-band (1.26 GHz) radar and an L-band (1.41 GHz) radiometer that share a single feedhorn and parabolic mesh reflector dish antenna. The 6 meter diameter reflector has a constant off-nadir look angle and rotates about the nadir axis at 14.6 rpm, providing a conically scanned antenna beam and footprint with a surface incidence angle of approximately 40 degrees. The reflector dish provides a radiometer footprint of 40 km. Range and Doppler discrimination are employed to process the radar backscatter to an enhanced 1 to 3 km spatial resolution, providing high resolution backscatter measurements within the 40-km radiometer footprint. The rationale is to combine the attributes of the radar and radiometer observations in terms of their spatial resolution and sensitivity to soil moisture, surface roughness, and vegetation. The constant look angle scanning antenna geometry allows acquisition of data across a 1000-km wide swath and accurate repeat-pass estimation of surface moisture and hydrologic status every 2-3 days globally.

This presentation reviews algorithm development and applications, and associated SMAP science objectives addressed through the baseline SMAP data products. We examine the capability of SMAP datasets for characterizing wetlands ecosystems, including inundation dynamics. We discuss the potential for provision of a new data record of the spatio-temporal dynamics of seasonally inundated and flood pulsed wetlands ecosystems.

This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

Keywords: Soil moisture, wetlands, SMAP, remote sensing

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A reappraisal of the palaeolake levels of Ntwetwe pan, Makgadikgadi, Botswana with particular reference to their elevation and ages.
McFarlane M.J., Vanderpost C.H., Eckardt F.D.

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Mangrove-Dominated Ramsar Sites: Potential Effects of Climate Change and Sea-Level Rise
McKee K.L.

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Based in part on their high vulnerability to degradation and habitat loss, mangrove and other intertidal forested wetlands are considered by the Ramsar Convention to be Wetlands of International Importance, Worldwide, 182 Ramsar sites include mangroves, the dominant vegetation in 34% of the sites (as of August 2006). Examples include the Parc National des Mangroves (Republic of Congo, 66,000 ha), Sunderbans Reserve Forest (Bangladesh, 601,700 ha), Ciénaga de Zapata (Cuba, 452,000 ha), and Wasur National Park (Indonesia, 413,810 ha). Although Ramsar mangrove wetlands are protected from some threats facing intertidal forests, they are vulnerable to global change factors. Changes in climate and sea-level will alter the distribution patterns of mangroves through their response to temperature, rainfall, and tidal inundation regimes. Based on satellite altimetry data from 1993 to present, eustatic sea-level rise (SLR) is occurring at a rate of 3.3 mm yr^-1. Eustatic SLR plus local land movement (subsidence) determines the total rate of submergence in a particular geographic location, i.e., relative SLR. Mangrove-dominated coastlines must build vertically and equal to the rate of relative SLR in order to persist in situ, or mangroves must migrate landward. However, mangrove migration may be limited due to natural or human barriers that prevent landward movement. Both physical (sedimentation and erosion) and biological (organic matter accumulation) processes contribute to land-building in mangrove ecosystems, but these relative contributions vary with geomorphic setting. Mangroves along sediment-rich shorelines with macro-tidal regimes have high accretion rates and will persist if vertical land-building rates equal local submergence rates. Changes in rainfall or land-use patterns may alter sedimentation regimes, however, leading to elevation deficits. Alternatively, excessive sedimentation may lead to burial of mangroves and/or higher elevations that allow invasion by non-mangrove or exotic species. Some mangrove ecosystems occur in oligotrophic environments with naturally low inputs of sediment, often in close association with seagrass beds and coral reefs. Such ecosystems have kept up with past SLR by peat formation, but may be vulnerable if SLR rates increase substantially. Predictions of how changes in climate and sea level might affect Ramsar wetlands dominated by mangroves will benefit from more information about 1) site-specific rates of sedimentation, elevation change, and subsidence and 2) potential interactions among global, regional, and local factors and their effects on mangrove habitat stability.
Keywords: sea-level rise, climate change, elevation dynamics, mangrove

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Riparian vegetation response to vertical template heterogeneity following a large infrequent flood disturbance in the Sabie River, RSA.
McLoughlin C., Pienaar D., Parsons M., Kotschy K.

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Riparian vegetation distribution patterns are determined by the interaction of biotic and abiotic factors, usually depicted as occurring spatially along longitudinal, lateral and vertical gradients. Many alluvial floodplain rivers in temperate climates, and wetland systems, exhibit a close association between lateral distance from the main channel, height above the channel, flooding frequency and vegetation distribution. In these rivers, plotting vegetation assemblages on cross-sections is effectual for describing lateral gradients of riparian vegetation distribution and associating this with flood pulse frequencies in the vertical dimension. However, in geomorphologically complex systems, such as the mixed bedrock/alluvial rivers of the Kruger National Park, arrangement of vertical heterogeneity may be associated with unique hydrogeomorphic patterns that influence the distribution of riparian vegetation, but not easily demonstrated with a two-dimensional cross-sectional approach. This study employs a three-dimensional, spatially explicit technique to quantify the vertical complexity of the mixed bedrock/alluvial Sabie River in the Kruger National Park. A geo-referenced vegetation survey was conducted four years after a large infrequent flood disturbance, to link spatial distribution of vegetation with elevation information, and the large flood allowed separation of past from immediate vegetation response patterns. We tested the relationship between vertical template heterogeneity and the distribution of newly recruited woody vegetation by measuring species abundance and complementarity between different elevation positions. The Sabie River exhibits a complex pattern of juxtaposed elevation patches along the macro-channel floor, with no generalised relationship between lateral distance from the channel and height above the channel. The large infrequent flood disturbance did not ‘wipe the slate clean’, rather generated a complex biotic-abiotic patch mosaic in the post-flood river landscape. Although abundance within woody species was changed drastically, overall the large flood did not change species composition within the river system, although newly recruited individuals accounted for 70% of woody species abundance post-flood. Results suggest that woody vegetation assemblages do not recruit and establish randomly across the vertical dimension, even prior to direct flooding disturbance impacts. In addition to the more well known (direct) flooding impacts associated with aquatic systems, considering differential adaptations of vegetation assemblages to disturbance impacts, such as flood shear stresses and anaerobic conditions via inundation, conditions generated by vertical template heterogeneity in the rivers of the Kruger National Park bestows differential habitat niches for species recruitment and survival. In these river systems, large sections of the riparian zone are only inundated sporadically when larger floods do occur, these being key events linked to ecological processes, such as germination. However, the findings of this paper suggest that vertical template heterogeneity, per se, plays an important role in the high biodiversity observed in these rivers. Further research is required investigating what mechanisms are governing spatial patterns of riparian vegetation, and response to this vertical heterogeneity, including distance to water table and the role of longer-term flow variability occuring in these rivers. Increasing anthropogenic altering of the natural flow regime, diminishing flow variability, impacting hydro-geomorphological processes occurring within the river systems of the Kruger National Park, may undermine conservation objectives aimed at maintaining riparian biodiversity.
Keywords: flooding river riparian vegetation heterogeneity vertical template

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The identity, value and ownership of the Okavango: implications for the present and future
Mendelsohn JM

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Restoration and Resilience of Internationally Important Deltaic Wetlands with Sediment-Pulsing
Mendelssohn I.A., Stagg C.L., Slocum M.G.

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Flood pulsing, climate change and regeneration dynamics of Ramsar sites along the Mississippi and Gangetic Floodplains
Middleton B.A., Guetersloh M., Shimp J., Brown M.

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Shifts in water availability related to climate change have the potential to alter the regeneration dynamics of plant species on floodplain wetlands. Climate change predictions differ for Ramsar sites of the Mississippi and Gangetic Floodplains in the U.S. and India, respectively. For the central U.S., the Intergovernmental Panel on Climate Change (IPCC) predicts hotter and drier climates with occasional severe flooding from intense storms; for central India, the National Centre for Medium Range Forecasting predicts a hotter wetter climate punctuated by unpredictable monsoons and extreme droughts. Thus, climate change could affect the biodiversity of Ramsar wetlands in both floodplains because the regeneration of species from the seed bank is dependent on local moisture availability. In Taxodium distichum (baldcypress) swamps in North America, latitudinal studies show that woody species recruitment and other functions are higher in the northern, and central part of the range, respectively. Ramsar sites under study in the baldcypress swamp region of the U.S. include the Cache River/Cypress Creek in the State of Illinois (northern), and White River in the State of Arkansas (central). This study suggests that the effect of climate change may vary in Ramsar sites of the same vegetation type, but at different latitudes. Similarly, the regeneration dynamics of monsoonal wetlands in India are driven by moisture availability, based on studies conducted in the 1980’s. In the Keoladeo National Park in the State of Rajasthan, India, years of recent drought have reduced the flooded areas of these monsoonal wetlands of the floating grass, Paspalum distichum. After the park flooded in 2009, a brief survey concluded that the majority of aquatic species persisted at sites as seeds in the seed banks. While many aquatic species can persist in seed banks, little is known about how these species may survive under the conditions predicted under climate change scenarios. Many Ramsar sites have been affected by water diversion, so that biodiversity loss may become more extreme with climate change. Along the Cache River/Cypress Creek in Illinois, a partial reconnection of the upper and lower portions of the river is being considered to reconnect flood pulsing and migration routes. Projections of the effects of climate change on the biodiversity of Ramsar listed wetlands is limited by the lack of information on the responses of aquatic species to climate change environments including water availability/delivery, CO₂ and temperature.
Keywords: water regime, drought, aquatic plants, monsoonal wetland, baldcypress swamp

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Ecohydrological Modeling of Spatiotemporal Patterning in Pulsed Wetlands: the Florida Everglades as a Case Study
Miralles-Wilhelm F

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A numerical model has been developed to simulate the spatiotemporal patterning of ridge and slough landscapes in wetlands, characterized by elongated hummocks and hollows that occur parallel to the direction of water flow. The model formulation consists of governing equations for integrated surface water and groundwater flow, sediment transport, and soil accretion, as well as litter production by vegetation. The model simulations show how the spatial pattern self-organizes over time with the generation of ridges and sloughs through sediment deposition and erosion driven by the water flow field. The spatial and temporal distributions of the water depth, flow rates and sediment transport processes are caused by differential flow resistance due to vegetation and topography heterogeneities. The model was parameterized with values that are representative of the Everglades wetland in the southern portion of the Florida peninsula in the USA. Model simulation sensitivity was tested with respect to numerical grid size, lateral growth parameter and rate of production of litter by vegetation. The characteristic wavelengths of ridges and sloughs in the directions along and perpendicular to flow that are simulated with this model are consistent with observed patterns in the field. Also, the simulated elevation differences between the ridges and sloughs are of the same order of those typically found in the field. The width of ridges and sloughs was found to be controlled by a lateral growth distance parameter in a simplified formulation of litter production rate; this confirms earlier modeling results in which a differential peat accretion mechanism alone cannot reproduce observed ridge and slough widths. The results of this work suggest that this lateral growth occurs as a result of vegetation’s ability to grow laterally by production, enhancing sediment deposition in ridge areas, and balanced by increased sediment erosion in slough areas to satisfy flow continuity. The interplay between sediment transport, water flow and litter production time scales needs to be explored further through detailed field experiments, using a model formulation such as the one developed in this work to guide data collection and interpretation. This should be one of the focus areas of future investigations of pattern formation and stability in ridge and slough areas.
Keywords: Ecohydrology, modeling, ridge and slough, patterning, Everglades

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The role of wetland in carbon cycling and climate change
Mitsch W.J., Bernal B., Zhang L., Mander U., Nahlik A.M., Sha S., Anderson C.J.

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Discussion - Floodplain Ecohydrology
Mitsch W.J., Wagner I.

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Three Gorges Dam reservoir in southwestern China: An opportunity for enhancing ecosystem services of new floodplains
Mitsch W.J., Lu J., Yuan X., He W., Zhang L.

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Our paper explores the impacts and opportunities of the new unprecedented hydroperiod amplitude behind the Three Gorges Dam in China, the potential ecological and human systems that will result on the riparian edges of this reservoir upstream of the dam, and possible ecological engineering approaches that might minimize the impacts or enhance the ecological services that may be created with this new pulsing ecological system. The reservoir has already seen the relocation of over a million people but the question is, will new wetlands, riparian ecosystems and agroecosystems thrive with this unique high-amplitude hydroperiod and provide the necessary ecosystem services? The reservoir behind the Three Gorges Dam on the Changjiang (Yangtze) River in Hubei Province, China, was topped off at 170 m above sea level in the winter of 2008-09, 5 m less than originally designed. With this flood level, some relocated cities, homes and farm fields were seasonally under-water and a set of new unique riparian wetland ecosystems started to develop. Flooding in the pool behind the dam may eventually extend 600 km upstream to the city of Chongqing. The reservoir could have an amplitude as high as 30 m (wet in winter; dry in summer). Opportunities exist for optimizing ecosystem services in these new riparian systems through application of ecological engineering principles. Algal blooms were widespread in the early reservoir during flooding in 2008 so nutrient management will need considerable attention. Cascading terraced ponds/wetlands could be developed and mudflats will be abundant near or at the river in summer, providing an ideal habitat for shorebirds and other wading birds. Commercial enterprises for food production can be designed to utilize the pulsing water including fish net systems and natural-fertilization agriculture. Sedimentation of nutrients, especially phosphorus, could be significant during flooding and a “green” agriculture which is more harmonious with the new hydroperiod could flourish.
Keywords: Floodplains, Flood pulses, Three Gorges Dam, China, Ecological Engineering

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Effects of fire and flood pulse on the aquatic biogeochemistry of channels and floodplains of the Okavango Delta
Mladenov NM

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Fire is a common occurrence in the Okavango Delta of Botswana, known to have important consequences for dryland and floodplain flora and fauna. There is anecdotal evidence that fires may also impact water quality, especially just after the arrival of the annual flood, and this can have important effects on aquatic life. We analyzed biogeochemical data, including dissolved organic carbon (DOC) and dissolved oxygen (DO) concentrations, from a well-studied channel-floodplain system on the Boro River that burned in May 2002 and two adjacent floodplains (one burned and one unburned) near the Ngoqa River. We found that the annual flood, which arrived just after the fires, flushed burned and partially burned detritus into the water column, resulting in two to three-fold increases in conductivity (from approximately 80 to 150 μS cm^-1) and DOC concentration (from 9 to 25 mg C L^-1), and a peak in total dissolved nitrogen concentration (at 3.65 mg N L^-1 immediately post-fire that decreased to approximately 0.8 mg N L^-1 later in the season). Burning of organic matter is expected to produce residues rich in aromatic compounds and, indeed, UV absorption of DOM in the 250-280 nm range, where aromatic carbon compounds are known to absorb light, was highest in the post-fire period. However, the molar absorption and fulvic acid content of the organic matter in post-fire samples were not notably different than during years without an observed fire influence, suggesting that, on a molar basis, the pool of organic matter had not necessarily become more aromatic and recalcitrant. Respiration of large amounts of organic matter flushed into the water column depletes oxygen and is likely responsible for lower DO concentrations measured during the post-fire period than in subsequent weeks. Additionally, increased color associated with high DOC concentrations limits the depth of the photic zone and has a negative shading effect on primary productivity. This could, in turn, limit oxygen availability at deeper depths and negatively impact aquatic organisms. Within two-three weeks of the flood pulse, all solute concentrations returned to levels observed during previous years. Climate change is expected to exacerbate fires in dry regions and this scenario can further affect aquatic biogeochemistry in wetlands where the flood pulse conveys particulate and dissolved materials from the terrestrial compartment to the water column.
Keywords: fire, organic matter, fluorescence, absorbance

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A Hybrid Approach for Flow Partitioning in the Okavango Delta
Moalafhi D.B., Parida B.P.

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Environmental Flow Requirement being key to sustainable maintenance of any riverine or deltaic system necessitates the daily or monthly flow information in the system under study. Since large riverine or deltaic systems are influenced by very complex flow dynamics, simulating flow in such systems through conceptual or systems models approach may be extremely difficult as such systems are subjected to substantial exchange of flow between the main channel, the flood plains as well as other hydrologic processes such as evapotranspiration and infiltration. In this study an attempt has been made to use a hydbrid approach through which to use artificial intelligence models such as the Artificial Neural Network (ANN) model has been used in conjunction with the flow outputs from other type of models to partition the surface flow into other downstream channels within the system. Therefore an attempt has been made in this study to forecast flows in the Rivers Lopis and Gadikwe through partitioning of forecasted flows at KM-Junction in the Maunachira System of the iconic Okavango Delta. Using monthly flow data between October 2005 and July 2008 at the KM Junction, flows for August and September 2008 have been forecasted using stocahstic approaches and then these forecasts have been partitioned using a single input -multiple output type ANN model. It was found that using an ARIMA (1,1,1) model the forecasts at KM - Junction matched quite well with the observed monthly flows in August and September 2008. Using these forecasts along with previously observed flows at the KM-Junction, the partitioned flows at Lopis and Gadikwe for these months were 21.92,19.21 and 35.35, 31.44 million cum. Respectively compared to the observed values of 22.18,17.42 and 36.40, 30.40 miliion cum. Thus use of such models in the hybrid mode for forecasting flows in other branched river systems of the delta is quite promising.
Keywords: Artificial Neural Network, Flow Forecasting, Single Input Multiple Output System,

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Challenges and Opportunities Associated with the Biodiversity Mainstreaming Approach: The Case of the Okavango Delta Ramsar Site, Botswana
Moleele N,N., Magole I.L., Khwarae G., Mosepele B., Mosojane S.

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The Environmental Governance of the Okavango–Makgadikgadi Basins – the Okavango Delta, Boteti Drainage Basin and the Tributaries of the Systems
Monna S.

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Habitat partitioning and biological variability in two cichlid species of the Okavango Delta, Botswana
Mosepele K., Amutenya K., Masamba W.

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Habitat partitioning is one of the major factors that drive biological structure in fish populations of floodplain systems. The Okavango Delta is divided into two distinct habitats between the panhandle and lower Delta characterized by different environmental factors. Subsequently, some field observations and a preliminary study in the Delta revealed that there are differences in fish population dynamics of similar species between the panhandle and lower delta. Notwithstanding these, no study has explored the relationship between the environment and these observations in the Delta’s fish populations. Nonetheless, this spatial heterogeneity poses daunting fisheries management challenges in flood-pulsed systems. Long term water chemistry monitoring has revealed that mean temperature in the panhandle is relatively low (22.10C) compared to Nxaraga (22.30C) and Lake Ngami (25.30C). Furthermore, there are distinct differences in dissolved oxygen between these different areas where Nxaraga has extremely low levels (1.21 mg/l) compared to panhandle (6.74 mg/l) and Lake Ngami (6.55mg/l). Moreover, Lake Ngami has the highest pH levels (7.69) compared to panhandle (6.92) and Nxaraga (6.40). Similarly, preliminary results show that three spot tilapia (Oreochromis andersonii) in the upper panhandle have an extended spawning season (January to December) while the lower Delta fish have a truncated spawning season (May to October). Furthermore, a single factor Anova showed that there are significant differences (p=0.000) in mean size of three-spot tilapia between the two major habitats in the Delta where panhandle specimens are larger than lower Delta species. Moreover, while there were no significant differences (p=0.062) in mean size for male three-spot tilapia, there were significant differences (p=0.000) in mean length of female fish between the two habitats. This study will also explore for differences in growth of three-spot and red-breast (Tilapia rendalli) tilapia between the two habitats in the Delta and determine the major explanatory environmental variables for these observed differences. It is envisaged that knowledge gained from this study will contribute significantly towards knowledge of floodplain fish biology and management.
Keywords: habitat partitioning, floodplain fisheries, Okavango Delta, cichlids

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Fisheries dynamics in a fluctuating environment; relating fishery characteristics with the seasonal hydrological regime of the Okavango Delta, Botswana
Mosepele K.

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Is the flood pulse a major driver of ecological change in the fish community of the Okavango Delta, Botswana?
Mosepele K.

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This explores the relationship between the ecology and biology of several key species in the Delta’s fishery within the background of the seasonal flood pulse. While variability is inherent in floodplain systems, the effect of the flood pulse has never been conclusively establish in the Delta’s fish community. It is therefore important to establish these relationships to inform management . The major findings made in this study indicate that the Delta’s seasonal flood pulse is the major driver of ecological/ biological change in the Delta’s fish populations. The timing of migrations for breeding and feeding, the timing for actual spawning and generally most of the life history strategies of the Delta’s fish species are controlled by the flood regime. Seasonal changes in feeding ecology of most fish species were observed, where their diet varies between terrestrial and aquatic food sources depending on the flood regime. This suggests that at certain times of the year, there is direct energy flow into the fish community from terrestrial sources that are trapped by the newly arrived floods. A good example of this observation is the high proportion of termites in the diet of Schilbe intermedius when the floods arrive in the lower Delta. Another major observation is that due to the nature of the Delta, with its high inter and intra variability, the Delta’s fish species are generally resilient to changes in the hydrological regime as long as they fall within the natural variations. This based on the observation of some species that mouthbrood their eggs (such as Oreochromis andersonii, etc)which enhances the survial of their young even under adverse conditions. Species such as Hepsetus odoe make oxygen enriched bubble nests where they lay their eggs and this protects the eggs from low oxygen conditiosn that may be caused by variations in the flow regime. Other species such as the catfishes (especially the Clarias group) have vestigial lungs that enbale them to breathe atmospheric oxygen when also helps them to survive under adverse conditions. In conclusion, it is observed that the flood pulse is the major driver in the ecology and biology of key species in the Delta’s fishery.
Keywords: flood pulse, fisheries, ecological change, environmental flows, Okavango

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Fisheries management in flood pulsed systems: The Case of the Okavango Delta Fishery, Botswana
Mosepele K., Mosepele B.

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Floodplain fisheries worldwide are characterized by diverse fish species assemblages, diverse fisher groups and diverse fishing gears that harvest the different fish species that occur. The structure and nature of the Okavango Delta fishery is no different. Subsequently, these complex and dynamic systems, where the fishery is diffused in space and time, pose daunting management challenges. This paper aims to propose a management plan for floodplain systems, using the Okavango Delta as a case study. Approximately 71 different fish species occur in the Delta, which cover a wide range of sizes from the largest such as Clarias gariepinus (max = 1.4 m) to the smallest such as Barbus haasianus (0.032m); and are utilized by the different fisher groups. The Delta’s fish community structure (e.g. distribution, relative abundance, diversity, etc) undergoes spatio-temporal variations as a result of the seasonal flood pulse. Indeed the flood pulse has been established as the main driver of ecological change in the fish communities of floodplain systems. Notwithstanding, the Delta’s diverse species assemblage is harvested by over 3000 people divided into subsistence (the largest group using various fishing gears), commercial (a relatively small group using mostly modern gear such as gill nets and motorised boats) and recreational fishers (who are mostly tourists using modern rod and tackle). The fishery is a major source of livelihoods for most of the fisher groups and they use different fishing methods and different fishing gears as an adaptation to changes in fish availability in time and space. While classical fisheries management approaches (based on a top-down approach) have been applied in most floodplain fisheries, the Delta inclusive, the dynamic and fluid nature of these fisheries require a different approach that is holistic (and inclusive) in nature. Therefore, this paper will discuss the prevailing management of the Delta’s fishery and propose an approach that is more relevant and realistic to floodplain fisheries. This paper will argue that classical management approaches that are applied in floodplain fisheries are static and unrealistic in such dynamic systems. It is envisaged that this paper will contribute to the prevailing global debate on fisheries management, especially of inland freshwater systems, which are not only major sources of livelihoods, but are also fountains of cultural heritage.
Keywords: flood pulse, fisheries management, Okavango

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Impact of seasonal flooding on aquatic macroinvertebrates family’s assemblages in a seasonal floodplain in the Okavango Delta
Mosepele B.

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Aquatic macroinvertebrates are important component of primary production, which is variable, translated into higher trophic levels (e.g. fish biomass, bird biomass, etc); therefore, the availability of these organisms greatly depends on the availability and quantity of water in the floodplain. This study will use data on aquatic macroinvertebrates collected every two months for one year to examine the impact of seasonal flooding or environmental flows (eflows) on aquatic macroinvertebrates assemblages. The seasonal floodplain is characterized by a mosaic of grassy floodplain habitats, seasonal pools, lagoons, and a relatively more permanent riverine system, macroinvertebrates assemblages will invariably change due to changes in patterns and amount of flow. Results show that 6,423 specimens of aquatic macroinvertebrates belonging to 49 families were collected in the entire study area. The Corixidae family was the most abundant taxa followed by Coleoptera; whilst Atydae, Simulidae and Sciomyzidae were the least abundant families. Generally, spatio-temporal variations were observed in the distribution and abundance of macroinvertebrates families. Seasonal pools had the highest taxa abundance (with 2612 specimens), while marginal vegetation habitats had the lowest abundance (1008 specimens). Temporal variations in abundance were observed, where the highest total abundance (2477 specimens) was observed in February, the lowest total abundance (544 specimens) in November. These results suggest that changes in the flow regime of the Okavango River system are driving changes on the aquatic macroinvertebrates assemblages. Floodplain driven regime has a regulatory impact on the abundance of aquatic macroinvertebrates, which are critical for the maintenance of the food web, fish biomass in the system. Therefore understanding of the flooding patterns (the timing, the quantity and quality) of the flood are crucial for conserving biodiversity, regulate the system and ensure a cycle of continued production of macroinvertebrates which are important for maintaining the aquatic ecosystem. Any management decisions that may affect the timing and frequency of flooding, needs to account for regulatory nature of the flood regime on aquatic macroinvertebrates.
Keywords: aquatic macroinvertebrates, flood regime, Okavango

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Stakeholder participation in a multi-species fishery driven by a seasonal flood pulse; the Okavango Fisheries Management Committee and the co-management approach in Botswana
Mosepele B., Mosepele K., Moleele N., Ngwenya B.

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Floodplain fisheries are dynamic entities characterized by diverse species assemblages, dynamic spatio-temporal variations in fish populations, and complex fishery structures. Therefore, the complex nature of these fisheries, that of the Delta inclusive, pose serious management challenges. The diverse nature of the fishery, coupled with different utilization objectives (i.e. recreational trophy fishing vs. market based commercial exploitation), has created conflict over time between commercial and recreational fishers in the Delta. This conflict was seen as an antithesis to not only a comprehensive fisheries management regime in the Delta, but also as a major impediment towards fisheries development. A co-management approach, which resulted in the formation of the Okavango Fisheries Management Committee (OFMC), was subsequently developed to empower local management structures under an over-arching theme of co-management. Membership of the OFMC is composed of various key stakeholders in the Okavango Delta fisheries and fosters a partnership between government agencies, local authority structures, the private sector (including NGOs) and the University of Botswana. This paper will discuss the formation of the OFMC, the critical role it plays in fisheries management, and the bridges of understanding it has forged between stakeholders who used to be at variance. Through a consultative and democratic process, the OFMC produced a Code of Conduct as a conflict resolution mechanism in the Delta’s fishery. This Code essentially regulates behaviour that might otherwise break relations between the different stakeholders. Furthermore, while the Code is presently voluntary and not enforceable under the law, it is nonetheless a milestone in fisheries management of the Delta where past antagonists are now friends working towards a common goal. Furthermore, the OFMC, in collaboration with the Fisheries Division, has developed and implemented several management strategies in the fishery as part of the co-management philosophy. It is envisaged that this co-management approach can usher in a new era in fisheries management, where all the major actors have an input into the fisheries management regime. In conclusion, it is hoped that this management approach can be replicated in similar systems around the world.
Keywords: Fisheries, Co-management, Okavango Fisheries Management Committee

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Rural Livelihoods and Adaptation to Desiccation in the Lower Okavango River Basin
Motsholapheko M.R., Kgathi D.L., Vanderpost C.

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Adaptive management and scale in a flood pulsed system – the case of the Okavango Delta Management Plan, Botswana
Motsumi S.E., Cassidy L., Segomelo P.

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The flood pulse, as main driver of the Okavango Delta system, creates variable and adaptive responses in its abiotic, biophysical, socio-economic and institutional aspects presenting challenges for management. Further, resource use impacts have increased substantially in recent decades. This perturbation has led to the initiation of a systematic framework for management – the Okavango Delta Management Plan. The development of the plan and its subsequent implementation are based on the recognition of the dynamic nature of the system. We analyse the extent to which the ODMP accommodates adaptive management principles in its implementation. We focus on the scale aspects of institutional arrangements, and on the changes being made to facilitate local-level collaboration with regard to ecosystem management in order to allow flexible responses to variable conditions. Specifically, we examine the hierarchy of decision-making and highlight the challenges associated with scale mismatch. The coordination of ODMP implementation is the responsibility of the Department of Environmental Affairs, a central government institution based at district level. This presents challenges in that the ODMP is placed outside an already established district level planning framework, being North West District Council and District Administration. In coordinating the implementation of the ODMP, DEA has to work with local authorities, national level institutions and regional bodies such as OKACOM, presenting challenges of scale in management. While the plan is worded in terms of integrated ecosystem approaches, institutional arrangements are still founded on administrative boundaries, and not on social-ecological ones. Resource managers and users are still based in their original “silo” institutions. Scale effects compound this, because decision-making at the national level is sectoral, challenging the district implementing level’s efforts of integrated trans-disciplinary integrated responses. Centralised, sectoral decision-making has resulted in the ODMP being seen as an environmental management plan run by the Ministry of Environment, Wildlife and Tourism. The location and type of management structures are therefore critical. At district level the ecosystem approach is gaining ground through effective capacity building. Increasingly, district officers are adopting integrated, collaborative responses to management, as in the implementation of Integrated Land Use Plan – a product of the ODMP process. The ODMP is not a ‘traditional’ plan; it is more a framework of guiding principles and is not locked to fixed goals. It can accommodate other initiatives (eg. BIOKAVANGO project) and help integrate these into management of various resources. Though difficult to quantify, it has been a catalyst for change, which is visible at the district level in terms of informal and formal cross-sectoral consultations. The ODMP has strengthened local bodies such as the District Land Use Planning Unit and Okavango Wetlands Management Committee by providing a framework for cross-sectoral collaboration. To truly address the scale issue and break away from administration units as the basis for management, however, it would need up-scaling the ODMP to a basin-wide approach, arguably the most sound ecosystem management delineation. The tri-nation status of the basin, and how district and national level institutions can effectively respond to broader-scale effects, is a challenge being addressed by OKACOM.
Keywords: adaptive management, scale, governance, Okavango Delta Management Plan

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Floods, early warning systems and remote sensing application in northern Namibia
Mufeti P.F, Van Langenhove G

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Namibia is a dry country with limited seasonal rains and no permanent rivers. . In recent years, however, and first in 2008 and in particular in 2009, exceptional flood events took place in areas that have seen no or at the most ephemeral flows. Flood experiences in Namibia were as a result of inflow of water from upstream catchments in Angola and localized heavy rainfall. Climatic variability, land cover and use changes are also other contributing factors that complicate forecasting and increase flood risk factors. The floods in the Cuvelai were the highest in living memory, and in the Kavango and Zambezi river systems the highest in at least 40 years. Large areas of dried out deltas and lakes suddenly got inundated, and fossil river links were observed as active flow channels for the first time in recorded history. Floods were catastrophic for the local population, in terms of disruption of agricultural activities, damage to infrastructure, breaks in communication and induction of water-borne diseases like cholera and malaria. In 2009, the number of directly affected people was more than 677,542 which is 56 % of the total population in the flood affected area, which is where 60% of the Namibian population lives. The Namibian Government declared an official disaster situation in March of 2008 and 2009 for the northern regions affected by the floods comprising the Cuvelai, Caprivi and Kavango. . The United Nations Office for Outer Space Affairs (UNOOSA), through its platform for Spaced based Information for Disaster management and Emergency Response (UN-SPIDER) provided satellite based mapping of the contemporary floods. The flood maps which were used for flood assessment and management were critical for both real-time operational management and long-term planning. Direct access and conventional mapping methods were not possible during floods in these areas. . Flood information was disseminated and communicated to Government and NGO organizations involved with disaster management.
Keywords: Early warning Systems, Floods, Remote Sensing

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The influence of land-use land-cover change on waterfowl: a case study of Malagarasi River Sub basin, Western Tanzania
Mulokozi C.J., Perkins J.S, Ringrose S.

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Erosion and rehabilitation of the Molopo Wetland, South Africa – an overview of benefits to environment and society
Munzhedzi E., Grundling P.

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The Molopo wetland system is located in the headwaters of the Molopo River in the North West Province, South Africa, and comprise of permanently inundated peatland and floodplain with seasonal and temporary zones. Phragmites australis is the dominating vegetation in the permanent and wetter seasonal zones with hydrophilous grasslands dominating the seasonal and temporary zones. The wetland and its catchment are prone to high intensity rainfall events generating regular flooding. However, the peatland sections are more dependent on groundwater with the floodplain sections fed by runoff. The Molopo, akin to other wetlands in this region, is naturally adapted to handle these flooding events in being covered with dense wetland vegetation protecting the soil against erosion. However, the integrity and natural functions of this system were, compromised by land uses such as draining, cultivation, overgrazing and flow concentrating infrastructure such as culverts beneath road crossings. Indications, based on aerial photography studies and local knowledge, are that excessive erosion events are directly related to large rainfall/flooding events. Due to the hydrologic and biodiversity importance of this system Working for Wetlands (an South African Expanded Public Works Programme) implemented rehabilitation measures from 2002 combining proactive preventative measures with remedial interventions such as the infilling of drains, removal of dams and building of erosion control weirs. It also raise awareness and influence behaviour and practices impacting on wetlands, rather than focusing exclusively on engineering solutions to promote ecological integrity, water and food security,. Labour and contractors from the local community were employed during the lifespan of the project in order to optimise opportunities with respect to human well-being and poverty alleviation. This presentation will be examining some of the positive impacts on wetland and community alike.
Keywords: South Africa, Peatland, Rehabilitation, Community

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Flood pulsing as a determinant of plant species distribution in seasonal floodplains of the Okavango Delta, Botswana
Murray-Hudson M.A., Wolski P., Brown M.T., Heinl M., Davidson T.

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In the flood-pulsed Okavango Delta, a significant proportion of land area is inundated for a part of many years. Variation in extent, duration and depth of this inundation resulting from the interplay between climatic variation in the catchment and over the Delta, and various endogenic geomorphological and ecological factors, results in a complex mosaic of different vegetation communities. Each of these has different ecological roles in the Delta as a whole, governing nutrient flows to different consumer groups, which in turn belong to a predominantly aquatic ecosystem and a terrestrial ecosystem. Plant communities are highly dynamic over different temporal and spatial scales; understanding the drivers of this dynamism is critical to conservation management and eco-tourism, the main form of land-use in the Delta. The hydrology of the Delta is unusual in that the river pulse (originating ~1000 km away in Angola) is asynchronous with local rainfall. This study identified quantitative relationships between floodplain vegetation (species composition, functional form, richness) and flooding (frequency and duration). Based on flood frequency data derived from a time series of satellite imagery, a stratified random sample of 30 floodplains was surveyed for vegetation composition and frequency of occurrence. Hierarchical cluster analysis and ordination demonstrated strong correlations between species composition and flood frequency, duration, time since last flood and depth. Eight vegetation communities derived from cluster analysis were statistically significantly different. Species distributions along hydrological gradients were used to derive frequency and duration optima and tolerances from generalized linear models; averages of these parameters were significantly different between different communities. Species in infrequently flooded areas were flood intolerant, and indicative of disturbance and a succession trend towards open woodland. In seasonally flooded sedge communities, average depth was the strongest parameter, while in grasslands and aquatic communities, duration was the strongest correlate. The considerable compositional overlap between the three classes of regularly inundated floodplain suggests that species composition is simply related to extant hydrological conditions at the scale of the individual floodplain. These similarities also indicate that availability of propagules is not a constraint on community development in Delta floodplains, possibly because of the high degree of hydraulic interconnection.
Keywords: floodplain vegetation, hydroperiod, inundation frequency

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“Flashpoint:” an historical anthropology of contestations over Samochima Lagoon in the Okavango Panhandle, Botswana
Ngwenya B.N., Mosepele K., Mosepele B., Moleele N., Tlotlego S., Njwaki S.

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The perennial Okavango river forms the Okavango Delta in the arid northwestern Botswana. The river originates in Angolan highlands and flows into the country at Mohembo and runs a straight course for 100 km through papyrus-dominated swamp (known as the Panhandle) before forming a network of distributary channels that form the Delta proper. The Okavango Delta is the primary resource for all economic activities especially tourism, fisheries and agriculture production sectors . Although there is evidence of abundant biodiversity resources in the Delta, there is also evidence of extensive poverty in the area. Current research for instance, indicate that fish catch constitute 6 -10% of standing stock the Okavango fishery. Since fish stocks appear to be primarily a function of previous and current flood size, fishing activities by different groups is considered sustainable. However, conflicts between the various user groups intensify during low flood season in specific fishing grounds such as flood plains and lagoons adjacent concession and communal areas. It is estimated that there are at least seven ‘hot spots’ or ‘flash points’ between subsistence, recreational and commercial fishers in the Delta, one of which is around Samochima lagoon. Samochima village is a communal with 847 residents (387 males, 460 females). The village is situated 10 km from Shakawe and consist of a stretch of about 15 km along the west bank of the main Okavango river. The village has active fishers and village associations, a chief and 3 tourist companies whose lodges extend into the Panhandle for a width of approximately 7km. Lagoons are a major refuge for fish in the Delta, especially during low flood periods. Samochima lagoon is importance because of its accessibility to all the fisher groups, especially subsistence fishers who have limited resources to travel big distances for fishing. The paper documents the fascinating historical anthropology of Samochima lagoon as a flash point that epitomizes contestations and mediation of views, values, knowledge, governance, cultural identity, power differentials and ethnocentricity between and among the lagoon community of recreational, subsistence and commercial fishers.
Keywords: floodplain fisheries, Okavango Delta lagoons, socio-cultural relations, resource conflicts

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Effect of Hydrological Regime on the Macrozoobenthos Structure in Floodplain Lakes in Postglacial River Valleys in Poland
Obolewski K., Glińska-Lewczuk K., Kobus Sz., Burandt P.

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The role of hydrological regime, which is a driving force of essential ecological processes such as production, decomposition and consumption in river floodplain ecosystems, has been recognized as one of the key factors in the structure and functioning of riparian wetlands. The amplitude of the flood pulse and the time of inundation vary amongst floodplains, depending on the floodplain’s geomorphology and the river’s catchment area and climatic conditions. Hydrological regime of transitional zone of temperate climate is characterized by two distinct periods of an accelerated water circulation: first period results from snow melting during mid-winter (January –February) and spring months (March –April), while the second takes place in summer (June-July). The variable hydrological conditions imposed by the flood pulse pattern underpin a pronounced seasonal response in the macroinvertebrate composition in floodplain lakes. The impact of hydrological regime on the hydrobionts and specific process of river –flood systems we studied in 23 floodplain lakes located along the meandering sections of three river valleys: the Łyna, Drwęca and Słupia rivers located in the southern watershed of the Baltic Sea (N Poland). The research was carried out in the period of 2005-2009 based on quarterly sampling. In addition, hydrological data were available from water level loggers installed in each river channel (DT-Divers, van Essen Instruments, the Netherlands). The results of 5-year study, allowed us to identify 36 taxa of bottom organisms, among which Crustacea and Diptera dominated. The highest biodiversity we observed in those ecosystems which were periodically flooded, but daily changes of water were insignificant. We observed the highest abundance of benthic invertebrates in floodplain lakes with a seasonal depth range ~1.5 m, which tend to have short periods of hydraulic isolation as well as the frequent or permanent exchange of water. We found that macrozoobenthos dynamics in temperate floodplain lakes is likely to be just as variable as seasonal patterns of flooding and isolation. However, the changes in structure and biomass of the organisms are also related to their life span. Having in mind the Flood Pulse concept, we have found also that the existence of bottom macroinvertebrates is related to some physical properties of water (temperature, aeration, transparency) driven to a large extent by hydrological conditions. Due to the relatively low mobility of bottom invertebrates in water/sediment environment and a relatively simple method of the taxa identification, the hydrobionts may serve as indicative species of environmental health what follows the implementation of the European Framework Directive, aimed at restoring all aquatic ecosystems to good ecological status.
Keywords: macroinvertebrate, wetlands, flood pulse, rivers, Poland

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Estimation of hydrological characteristics of swamp communities, the Drweca River (N Poland) case study.
Okruszko T., Chormański J., Glińska-Lewczuk K.

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An appropriate hydrological regime within a wetland is essential to maintain goods and services. Dynamic convergence of groundwater-riverine components contributes to physical and functional complexity of vegetation patches in the floodplain landscape. Hydrologic gradients that can be established for each alluvial river valley promote the diversity of wetland communities and community types. In the case of swamps, long-lasting inundation is an essential hydrological phenomenon, which shapes the habitat characteristics. Since the inundation is formed by the river-specific conditions, the identification of environmental causes of floods, which are a significant source of water for the riparian wetlands, should be also considered. The minimum amount of water during the high flows, which should remain in the river, can be established by investigation of flooding frequencies of the natural habitats fed by the river water. Considering natural hydrological regime and relative small hydromorphological changes in the Middle Drwęca River valley (N Poland), we analysed four typical swamp ecosystems, namely: reeds, sedges, alder forest with willow bushes and macrophytes in oxbow lakes along its floodplain. The analyses were performed on representative sections of the alluvial river valley, characterized by a site-specific composition of vegetation communities. The estimation of water requirements of the Drwęca River Valley wetland was determined using the gauge relations method and historical water stage time series. For the 50 years historical water stage data, the frequency of flooding, and the average duration of flooding in each community was identified. The critical analysis of method accuracy led to estimation of average frequency of flooding for different wetland ecosystems. The results of simulation proved that the most important communities of the Middle Drwęca River Valley are characterized by a very long and frequent inundation period amounting to ¾ of the average year. The frequencies of flooding for particular wetland ecosystems are comparable to the results of the investigation (short term piezometric measurements) conducted in the other locations in the NE Poland. It concerns both periodically saturated floodplain soils and aquatic water bodies, where seasonal impoundments are necessary to the some macrophytes species development. This type of estimates should be used in order to establish the environmental flow for the river valleys which include the swamp habitats in order to meet the criteria of good ecological status under the Water Framework Directive. The proposed methodology demonstrates how using the simple hydrologic tools this estimates can be obtained.
Keywords: flood frequency, vegetation communities, hydroperiod

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Potential consequences of climate change to the Brazilian Coastal Plain Forest.
Oliveira V.C., Joly C.A.

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Adaptive responses to flooding by trees in four tropical floodplain ecosystems
Parolin P.

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Non-market valuation of wetlands in the Canadian prairie pothole region
Pattison J.K., Boxall P.C., Adamowicz W.L.

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Wetland conservation is an important issue in Canada, with approximately 20 million hectares drained or lost since 1800. Concern for this loss of habitat was confirmed when Canada signed the Ramsar convention in 1971 and the federal government enacted a wetland policy in 1991. The goal of this policy was to promote the conservation of Canada’s wetlands and to sustain their ecological and socio-economic functions, now and in the future. Unfortunately there is little economic information on the benefits and costs of increasing wetlands in Canada to fully implement this policy. The Canadian prairie pothole region is a relatively flat landscape punctuated by small “pothole” wetlands. Intensive agriculture is prevalent in the region, and since settlement has caused high levels of wetland drainage. This wetland loss has decreased ecological goods and services provision, such as carbon sequestration, flood and erosion control, biodiversity enhancement and water filtration. Quantification of the non-market values of wetlands will be an important tool to halt wetland loss and promote conservation. As economic markets do not capture the true value that wetlands provide to society, there is potential for major influence on government wetland policy in Manitoba. This may also serve as an example for studies in different regions that face many of the same obstacles to wetland conservation, such as the Okavango. A survey was designed to capture information from the Manitoba public on their perceptions of wetlands and what they would be willing to pay to preserve them. This survey includes information and questions on knowledge of wetlands, attitudes toward wildlife and habitat, agricultural practices and wetland policies. The second portion of the survey includes referendum questions asking respondents to vote yes or no to hypothetical wetland restoration options, allowing determination of non-market values for wetlands. A number of focus goups from the general public, water quality experts, and agricultural producers were conducted in order to design the survey as accurately as possible. This addressed many of this issues inherent in contingent valuation studies, such as hypothetical bias. The market based research company Ipsos Reed was hired to administer the survey to approximately 2000 individuals. In addition to the willingness to pay, information will be collected on some of the recreational interests, activities, and demographic information of the respondents. The final survey was conducted in January 2009 with approximately 2000 individuals. Results show the following: slightly pro-environmental sentiments, WTP estimates of approximately $300 per person, WTP exhibit sensitivity to scope, tax levels are significant and individuals are less likely to vote for the proposed program as tax levels increase, approximately 8% of individuals felt that wetlands should be conserved regardless of the cost (yea-sayers), about 40% of individuals who voted for the proposed program felt government could do more to protect wetlands in Manitoba and 40% of individuals felt wetlands should be protected for future generations. In summary: wetlands ecosystems are important to the general population and government has a responsibility to retain and restore them.
Keywords: wetlands, willingness-to-pay, ecological goods and services, contingent valuation

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Sustainable Rural Livelihoods - Boteti River: A case for wildlife and tourism-based CBNRM
Perkins J.S.

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Remote Sensing of Palm Swamp Distribution and Flooding Status over Sub-Regions in the Upper Amazon Basin, Peru, for Assessing Carbon Dioxide and Methane Release
Podest E., McDonald K., Zimmermann R., Horna V., Hess L.

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Palm swamp forests are widespread in the Amazon basin, including large regions along the Manú, Madre de Dios, and Mayo rivers in Peru. These wetland ecosystems form where seasonal flooding is moderate but surface inundation remains constant. The combination of permanently saturated soils, warm temperature year-round, and low oxygen in these palm swamp soils can lead to a large carbon release to the atmosphere, particularly as methane. However, little is known about the contribution of palm swamps to the overall carbon balance of the Amazon basin. Current land-atmosphere carbon flux models quantify carbon exchange between Amazonian palm swamps and the atmosphere based on consideration of the palm swamp forests as terra firme, which are known to release no methane. If palm swamps constitute a significant source of atmospheric methane, and if this methane release persists most of the year, fostered by high ecosystem productivity, better estimates may be obtained between methane models and atmospheric concentration measurements. Because of the widespread occurrence and expected sensitivity of these ecosystems to climate change, it is crucial to develop methods to quantify their spatial extent, inundation state, and carbon dynamics. Precise information on the extent and characteristics of palm swamps is difficult to gather because of their remoteness and difficult accessibility. Remote sensing is a unique tool for studying and monitoring these ecosystems. Active and passive microwave remote sensing provide the capability for acquiring images day or night, even under cloudy conditions, which are especially prevalent in tropical regions. We are developing a remote sensing methodology using microwave data to determine palm swamp distribution and inundation state over sub-regions in the Upper Amazon Basin where ground data is available. Information on palm swamp extent is being combined with eco-physiological data and measured surface methane release rates to assess spatially and temporally their carbon dioxide and methane release. SAR data from ALOS PALSAR is used to determine palm swamp forest distribution and a combination of QuikSCAT and AMSR-E to determine palm swamp forest inundation state on a bi-weekly basis. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.
Keywords: palm swamps, wetlands, methane, remote sensing, SAR

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A thirty-year evaluation of the flooding regime in Chobe Basin, Botswana and Namibia
Pricope NG

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Various water utilization scenarios for agricultural and urban use along the Chobe River in Botswana are being currently proposed. However, the unusual nature of the flow regime of the Chobe – both forward and reverse to and from the Zambezi, sporadic connections through Lake Liambezi with the Linyanti or with Selinda Spillway, variable contributions from local and regional precipitation, and other surface and groundwater connections with the Zambezi across the Caprivi Strip – means that the understanding of the hydrology or annual flow regime is relatively poor. Because some climate change predictions for Southern Africa indicate a potential reduction in river runoffs associated with changing patterns of precipitation and increasing temperatures, allocating water between ecological flows and economic and domestic uses will become more challenging, especially in the context of limited historical flow data. Moreover, interviews with local stakeholders reveal a change in the flooding extent of the Chobe River in the last thirty years. Fieldwork in the Chobe basin and research elsewhere in semi-arid flood-dependent ecosystems indicate a strong relationship between changes in flooding extents and vegetation structure. Also, t has been suggested by the literature and local stakeholders that there is a link between increasing bush encroachment in the Chobe floodplains in Botswana and Namibia and temporal and spatial modifications in the area flooded annually by the river. This paper presents a geo-spatio-temporal approach to estimate the nature of changes in the flooding extent and surface flow connections in the basin between 1986 and 2009. A time-series analysis of bimonthly Maximum Value Composite (MVC) NOAA Advanced Very High Resolution Radiometer (AVHRR, before 2004) and NASA Moderate Resolution Imaging Spectroradiometer (MODIS, after 2004) Normalized Difference Vegetation Index (NDVI) one-km resolution data was employed to determine flooded vs. non-flooded areas. The threshold between the water and land pixels was set using a simple intensity threshold technique and a four-class supervised classification (flooded, partially-flooded, minimally-flooded, and dry classes) was performed. Climatologic – mean monthly precipitation data between 1945-2008 at several stations in the basin – and hydrologic records – mean, max, and min monthly discharge data at Katima Mulilo between 1942- 2008 – were subsequently used to validate the remote sensing analysis. Results indicate that between 15% and 38% of the basin is flooded on an annual basis, with the maximum extent of the flooding occurring in 1991. A thirty-year trend analysis indicates a consistent decline in the mean monthly flooded area in the basin, significantly correlated with the trend in mean monthly discharge of the Zambezi at Katima Mulilo. The results of this study will be used to estimate the relative importance of flooding versus other drivers of change in determining vegetation dynamics through time in the basin and ultimately regional ecosystem resilience. They may also prove useful in future water utilization feasibility studies and in determining measures for protecting high flows through minimum flows and levels.
Keywords: flooding regime, Chobe River, remote sensing

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Fish responses to flood pulses in Australian rivers: interactions with land use and water extraction
Rayner T.

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From Australia’s tropical north to temperate south, flood pulses vary from highly predictable to highly variable. At all latitudes they play a major role in determining fish community structure and function. However, quantifying these dynamics is often confounded by interactions with human pressures, particularly land use change and water extraction. I will discuss this issue using data collected in two systems: (a) the Mulgrave River, in Queensland’s Wet Tropics; and (b) the Macquarie River, in the Murray-Darling Basin. In the former system, flows are unregulated, and more than 50% of off-channel habitats have been destroyed for agriculture. Flood pulses act as disturbances, because they are constrained within the deeply incised main channel. Instream primary and secondary productivity is reduced when sediments are reworked, leading to seasonal changes in fish community structure. Food web structure and function, however, remain relatively stable at the river reach scale, as fish move between mesohabitats to target their preferred prey items. In contrast, flows in the Macquarie River are heavily regulated and flood pulses are determined largely by water releases from upstream dams. Here, flooding has the opposite effect: improved hydrologic and biotic connectivity results in increased primary production. s“. Fish richness and abundance increases significantly during flow events, as fish expand their ranges from isolated waterholes into newly available habitats. Development of conceptual and numerical models in both the Mulgrave and Macquarie rivers has improved conservation outcomes, but there are still substantial impediments to effective management. For example, I conducted an aerial audit along a 990 km of streams in the lower Macquarie River and discovered more than 20 illegal barriers. Such structures may dampen fish responses to flood pulses by limiting movements, redirecting environmental water onto private property and undermining remediation actions at adjacent, legal structures.
Keywords: flood pulses, fisheries, land use change, Australia

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Linking Hydrology and Biogeochemistry to assess the impact of Lateral Nutrient Fluxes
Rebel K.T. , Osch, van F., McGuire K.J., Rastetter E.B., Wassen M.

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Mapping seasonal patterns of inundation in the Nile Basin from ALOS PALSAR data
Rebelo L.-M.

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Seasonal cycles of flooding and burning within the Okavango floodplains, Botswana
Rebelo L.-M, Hess L, Wolski P

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Is Marsh Plant Community Restoration in Iraq's Mesopotamian Marshes Doomed by Decreased Flood Pulsed Dynamics?
Richardson C. J.

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Iraq’s Mesopotamian marshes were once the largest wetlands in southwest Asia and covered > 15,000 square kilometers (km²) during spring floods, an area nearly twice the size of the original Everglades. Pulsed water events from spring snow melt in the mountains of Turkey, Iran, and Syria were the driving force that supported the vast expanse of marshes with annual inputs of water and sediment. The marshes were once famous for their biodiversity and cultural richness and originally the permanent habitat for millions of birds and a flyway for millions more migrating between Siberia and Africa. However, by the year 2000 less than 10% of the area remained as functioning marshes due to a systematic plan by the Iraqi government to ditch, dike and drain the marshes. Pulsed water conditions that historically developed and sustained the marshes in Iraq are now controlled by a series of internal dams and external water reallocations in Turkey, Syria and Iran. Recent data on water budgets and an USACE HECResSim model for Iraq water resources suggest a significant loss of water upstream for urban, agricultural and reservoir needs. This coupled with projected Iranian, Turkey and Syrian water resources demands suggests a much reduced area of restored marshes in the future. However, during recent high snow melt years more than 55% of the original marsh had been reflooded or was covered by marsh vegetation according to UNEP satellite analysis as of December 2008. However, re-flooding alone does not equate to restoration since water is often found to be saline and water flow is restricted by extensive dikes, further increasing salinity. However, when proper hydrologic and water quality conditions are restored marsh vegetation recovery is rapid. Recent studies have shown that three years after re-flooding plant community structure and productivity have increased to near historic levels and changes in ecological diversity for key trophic levels in the marshes are also restored. For example, overall recovery of ecosystem functions (plant productivity, hydrodynamics etc) reached nearly 50% of historic values for three restored marsh areas by 2006, only 3 years after reflooding. Seventy-four bird species were found by 2006, but total numbers were considerably lower than historic records. Unfortunately, the national and international demands for water from the Tigris and Euphrates Rivers for agriculture and urban demands along with a current drought severely threaten the future water supplies for the marshes and in turn the continued restoration of the plant and animal communities of the marshes. The present water demands, water quality and regional needs, which may alter the future of the marshes, are analyzed.
Keywords: Mesopotamian Marshes, Iraq, Iran, Restoration

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Pulsed Water and the Restoration of the Everglades: Can it be successful without the application of ecological guidelines?
Richardson C.

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The Everglades is the largest alkaline fen or subtropical mire in the United States. Because of its size, floral and faunal diversity, and geological complexity the hydrological restoration of the Everglades is considered by many peatland ecologists to be extremely complex and cannot be restored by simply controlled pulsed water additions. In addition to the severe human alterations of the hydrologic patterns in the Everglades there have been significant changes to nutrient cycling from heavy loadings of phosphorus and other nutrients as well as mercury problems. These changes in nutrient loadings have occurred mainly in the northern Everglades due to increased runoff from agricultural lands, eutrophic Lake Okeechobee outflow and urban storm water. In the newly proposed restoration plans (U.S. Army Corp of Engineers and South Florida Water Management Division, 2009) the concept of adaptive management is suggested as a means to reduce uncertainty in terms of biotic responses to the newly created hydrologic regimes and concomitant fire and nutrient regimes. However, it is clear that little is known about the dynamic interactions between hydrology, fire and nutrients in terms of maintaining Everglades’s communities. More importantly no specific peatland hydrodynamic goals are given in the U.S. governments restoration plans in terms of the acreage required to maintain community types or diversity on the landscape nor are any of the ecological conditions necessary to restore each community considered in any detail. The current plan as constituted focuses primarily on water supply, water storage and a delivery system for the growing population of south Florida. The Everglades in this approach is simply the conduit for water flow south. The ecological consequences of significantly increasing water flow southward and the importance of pulsed flow in Everglades communities is discussed. I will address a number of these issues and present a framework for hydrologic restoration of the Everglades.
Keywords: Everglades, restoration, pulsed systems, ecological guidelines

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Aspects of change in Delta ecosystems in response to past drying trends
Ringrose S., Cassidy L., Matheson W., Huntsman-Mapila P.

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Work is being undertaken around the periphery of the Okavango Delta to determine the nature of change in key ecosystems. The kinds of changes anticipated range from groundwater declines, surface water losses, changes in soil structure and vegetative response, in addition to changes in the natural resource potential in support of local livelihoods. In this way changes which have already been observed on the Delta periphery may be used to predict the kinds of changes anticipated through various climate change models and flow scenarios in order to inform policy on land use designations. One approach to assessing these kinds of transformations is being undertaken at a preliminary level using remotely sensed data. Single date medium resolution imagery (for instance Landsat) can be used to provide a broad overview of landscape level changes by considering landscapes close to the Delta periphery and comparing them with comparable areas at a greater distance form the wetland margin. Results from the western and southern margins of the Okavango Delta system suggest that ‘over time’ initially island woody vegetation cover locally invades the intervening flood plains developing protected ecotonal areas which are densely treed, relative to adjacent, non-protected floodplains. Over longer time periods former floodplain areas between the initial woody outgrowths also become infilled with woody vegetation leading to ‘island’ enlargement as the cover and soil types response to increases in litter decomposition, better shading and enhanced habitat quality. Improved soil conditions lead to better cultivation potential and higher tree densities which in turn generates a greater availability of fuelwood. Hence drying can produce potential positive changes in local livelihoods where these are managed effectively. Obvious disadvantages of Delta drying include a reduced availability of wetland-based resources including fresh water, fishes and reed and sedge availability for construction purposes. The availability of readily available groundwater resources in dried areas requires further work.
Keywords: drying, vegetation change, Okavango Delta

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Interactions of flow pulses and ecosystem metabolism in a floodplain river, southeastern Australia
Ryder D., Burns A., Robertson A.

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Floodplain river systems are characterized by hydrologic variability, and concomitant pulsing in productivity and diversity following flooding. Floods are thought to be essential in maintaining biogeochemical cycles fundamental to the ecological integrity of rivers and their floodplains, but these concepts are rarely tested at the river scale. We tested a prediction of the extended Flood Pulse Concept of river function that in-channel flow pulses provide significant functional benefits to rivers, similar to those produced by floodplain inundation. We estimated the magnitude and direction of exchanges of POC and DOC between the river channel and floodplain wetlands (billabongs) along a 140 km reach of the Murrumbidgee River in southeastern Australia during a planned environmental flow pulse. We also quantified ecosystem metabolism at two spatial scales; single-point open system methods at multiple stations along the river system, and using sealed chambers to estimate rates of carbon sequestration in floodplain wetlands connected during flow pulses. There was significant net transport of organic carbon from the river to all billabongs during connections, ranging from 87-525 kg POC and 36-4357 kg DOC. For one of the billabongs for which we had estimates of whole system metabolism the input of carbon from the river was equivalent to 12% of net annual aerobic carbon demand for the billabong. At the river scale, the flow pulse was net heterotrophic at all sampling station irrespective of localized inputs from connected floodplain wetlands. At the reach scale there was a net loss of 754 tonnes POC from the river channel to riverbank and floodplain habitats. At the same time there was a net gain of 821 tonnes DOC to the river channel, and this input could support riverine microbial respiration for approximately 54 days. The results demonstrate the importance of understanding organic matter dynamics in hydrologically variable floodplain river systems, with net gains and losses identified for different fractions of organic matter from different riverine features experiencing a range of antecedent flow conditions. Knowledge of the biogeochemical consequences for food chain development arising from the interaction between flow and organic matter in these systems is becoming increasingly important as climate change models predict increased drought cycles for many semi-arid regions of the world.
Keywords: environmental flow, floodplain river, productivity, carbon budget

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Tourism for Development? Sustainability, Poverty Reduction and Conceptualisation of the Limits of Growth in Tourism in Developing Countries
Saarinen J.J.

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Tourism is regarded as one of the largest and fastest growing industry in the world. The growth and impact of tourism have led to a range of evident environmental, social, cultural, economic and political problems in tourism destinations areas, creating a need for alternative and more environment and host-friendly practices in tourism. At the same time, tourism’s role is also seen positively in the global policy contexts such as United Nations Millennium Project and its goals and targets. Based on this tourism could, and should, be increasingly seen and used as a development tool for poverty reduction, ensuring environmental sustainability, developing a global partnership for development and the empowerment of previously neglected communities and social groups, for example. In particular, the issue of sustainable tourism has been given a central position in these development goals and discussions. Academically the concept of sustainable tourism has both fascinated and irritated scholars, and it has aroused a theoretical and practical confusion and harsh criticism. As a result of this there is need to understand the role of tourism in sustainable development contexts and how the limits of growth can be defined and set in local-global nexus. This research paper seeks to contribute to our understanding of the connections between sustainable development and tourism and especially in research into the potentiality of tourism as a tool for sustainable development and poverty alleviation under the changing social, political and environmental contexts in developing countries, in this case Botswana and Namibia. The purpose is to discuss how the development of tourism is driven and aimed to be used in sustainable development contexts and goals and how the roles, impacts and limits of growth of developing tourism are seen and set in different socio-spatial scales. Thus, the aim is to study how increasingly globalised and non-locally based tourism industry could be used as to tool for local and regional development in developing countries contexts; what are the socially constructed limits of growth in tourism development; and how they are characterized, known and set in tourism and regional development policies and related discourses and practices. The empirical study focuses on the development, role and sustainability of tourism in southern Africa.
Keywords: sustainable tourism, limits of growth, development, community-based tourism, poverty alleviation

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Water availability and requirements by communal livestock in an ephemeral river catchment in South Africa
Samuels MI

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The contribution of wetlands to livelihoods and economic growth in the upper reaches of the Okavango River Basin
SARAIVA R, BARNES J

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Water sources for trees along the Kuiseb River in Namibia differ for species and age groups
Schachtschneider K, February EC

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Neglected and difficult cousins of the river spectrum: ensuring ecosystem integrity and sustainable use of ephemeral rivers
Schachtschneider K

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Large parts of Southern Africa are arid and many of the rivers and wetlands in these areas are ephemeral, flooding for less than 10 % of the year. Ephemeral rivers flood erratically and most water associated with them is found as groundwater. Several million people inhabit arid parts of Namibia, Botswana and South Africa, giving ephemeral water sources in the region a higher per capita importance than their volume of available water suggests. In Namibia, ephemeral rivers are termed ‘linear oases’, as not only humans, but many other life forms depend on river goods and services in otherwise inhospitable surroundings. The intermittent flow conditions of ephemeral rivers do not allow the typical perennial diversity of aquatic and semi-aquatic fauna and flora to establish. Instead terrestrial life forms, primarily trees and shrubs are the most permanent life forms associated with ephemeral systems. Climate change, population growth and development needs all place an ever growing pressure on these water-limited ecosystems. Careful management is essential to ensure that human water needs are met, without jeopardising the ecosystems associated with these extreme river systems. This is however easier said than done. In the river spectrum from perennial to ephemeral, the river ecology and functioning of ephemeral systems is the least understood. They are very difficult to study because of their unpredictable hydrology, strong groundwater association, remote location and larger terrestrial than aquatic life form components. None of the reputed environmental flow assessment methods from South Africa can be applied to these river systems, as the method components do not fit with ephemeral river functioning. Alternative methods are in the process of being developed in South Africa and they do encompass and highlight the scientifically and logistically challenging aspects of groundwater and hydrology. It is however also imperative to stress that new methods for ephemeral rivers need a shift in ecological perspective from a traditionally aquatic outlook to one that is more inclusive of terrestrial ecology. More interdisciplinary cooperation and lateral thinking between aquatic and terrestrial ecologists is crucial, so that the frequency, magnitude, predictability and duration of floods and associated groundwater recharge are assessed in terms of water needs of woody riparian species as well as associated terrestrial fauna. Southern Africa can look at successful approaches in the arid United States and China, where dam releases have previously been informed by the needs of riparian tree species. The closest non-riverine approaches in South Africa so far address the broader category of groundwater dependent ecosystems from an ecohydrology perspective – but that still excludes the importance of flood pulses.
Keywords: Keywords: ephemeral, ecosystem integrity, environmental water requirements

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The St. Lucia estuarine lake system – a review of drought induced changes and management options.
Scharler U.M., Perissinotto R., Stretch D., Taylor R., Carrasco N., Crystal C., Lawrie R., Miranda N., Pillay D., van der Molen J.S.

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The St. Lucia estuarine lake system comprises 80% of the estuarine area of KwaZulu-Natal, and about half of the entire South African estuarine area. It has been declared not only a World Heritage Site, but also a Ramsar Site, and is the oldest protected estuarine system world-wide. Since most estuaries along the KwaZulu-Natal coast are temporarily open/closed estuaries (TOCE) and are relatively small in size, this large estuarine system serves an important role in terms of estuarine habitat and productivity. Its value as a fish and crustacean nursery is estimated to be R 600 million per annum when it is functioning properly. The system has been altered through freshwater abstractions in the catchment, and the separation from the Mfolozi estuary with which it historically shared an opening to the sea. This connection served to stabilise the mouth and to provide freshwater to the St. Lucia system, which was especially important during drought years. During the last drought period, the mouth remained closed for 7 years (2002-present, except a short opening in 2007 induced by high ocean swell), the lakes frequently turned saline (up to 200 ppt) and water levels dropped dramatically leaving wide areas of formerly inundated areas dry (up to 70%). A hydrodynamic model has been developed, drawing attention to the importance of the connection between the Mfolozi and the St. Lucia system. As a consequence of the drought, fish recruitment is hindered which is apparent from a low number of recruits in the estuary and the nearby ocean. In addition, the estuarine resident populations of zooplankton, macrobenthos and meiofauna have declined in biomass. This information is currently being incorporated into ecosystem models, following a time-series of seasonal variations over several years of empirical data, thereby characterising ecosystem behaviour during a severe drought period. Possible management solutions for the near future are in concordance with the history of the S. Lucia-Mfolozi system: (1) Slow down and reverse catchment degradation (2) part or all of the Mfolozi floodplain is rehabilitated to natural land restoring its sediment trapping capacity and (3) restore natural functioning of the combined Mfolozi - St. Lucia Mouth.
Keywords: St. Lucia, Mfolozi, drought, water levels, salinity, biomass, hydrodynamic model, ecosystem model

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Modelling the effects of surface water flood pulses on groundwater
Schot P.P., Wassen M.

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Challenges for sustainable management of flood-pulsed ephemeral rivers
Seely M.

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Desiccation factors affecting community life in the Mopipi area, Boteti River, Botswana
Segosebe E.M., Chanda R.

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Cross-comparison of Jason 2, ICESat and Envisat data: Potential of spatial altimetry for floodplain monitoring in Brazil
Seyler F., Calmant S., Filizola N., Mazzega P., Frappart F., Durieux L., Bonnet M.-P., Da Silva J., Cochonneau G.

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Zooplankton distribution and production in floodplains of the Okavango Delta with different history of flooding frequency, Botswana
Siziba N., Ramberg L., Chimbari M.J., Mosepele K.

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Grazing by Black Swans Cygnus atratus on a seasonally-flooded wetland
Smith A. N.

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Little is known about the effects of grazing by birds on seasonally-flooded Australian wetlands. The Clarence River floodplain, on the east coast of Australia, once contained many wetlands of outstanding habitat for large numbers of waterbirds. Historic drainage altered the local hydrology, destroyed the natural flood pulse effect, and drastically decreased the habitat values of these wetlands and the numbers of waterbirds. Prior to drainage, in varying seasons, mobile populations of Black Swans Cygnus atratus numbered over 10,000 per suitable wetland where they foraged and nested, but now typically number less than 100 per wetland, with few nests. Grazing by Black Swans was observed to have an obvious visual impact in Little Broadwater, an ecologically-important wetland on the Clarence River floodplain. To measure this impact, swans were excluded from part of the wetland from March to September in 2007, to determine their impact on the structure and biomass of marsh vegetation, and consequently on the habitat available to other waterbirds. After 135 days, the mean above-ground biomass of the dominant sedge Eleocharis equisetina was significantly less in grazed sites (607 ± s.e. 81 g.m^-2) than in ungrazed sites (1259 ± s.e. 177 g.m^-2) (a difference of ~6.5 tonnes / hectare). This difference was mostly due to the loss of leaf biomass above the waterline in grazed sites. Black Swans grazed preferentially at water depths of at least 15-20 cm, although they moved into shallower areas after depleting the above-water food source in deeper areas. Grazing by Black Swans can have an impact by creating open water resulting in more habitat for other birds such as wading birds (e.g. Royal Spoonbills Platalea regia) and dabbling ducks (e.g. Grey Teal Anas gracilis). Grazing by Black Swans is an important component of the ecological function of these wetlands. Where water levels can be artificially manipulated, local wetland managers could attempt to restore the flood pulse to wetlands that are large enough to sustain Black Swan populations in order to retain a variety of other waterbirds that require open water.
Keywords: Black Swans, Cygnus atratus, grazing, wetlands, Clarence River, floodplain, Australia

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What causes the variability in Okavango River flow?
Todd M.C., Wolski P., Mackay A., Davidson T.

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The annual cycle of the Okavango River discharge is the “heart beat” of the Okavango delta pulse flood system. However, the river flow exhibits pronounced variability at a range of timescales beyond the annual cycle. This has long been recognised both in the timeseries of river flow above the delta panhandle and in records of the extent of delta flood. The low flow and suppressed delta flooding in the mid 1990s is a well known expression of the variability. This variability in the extent of floodplain inundation contributes to high habitat diversity across the Okavango Delta. However, to date, little systematic evaluation has been undertaken to determine which climatic processes over the upstream basin actually cause the variability in river flow. Understanding variability in tropical convective rainfall over the basin region in Angola is important for interpreting climate model projections of future changes in rainfall and hence the Okavango River flow. In this paper we use the long term record of peak season (Jan-June) river flow at Mohembo from 1933-2008 to determine the climatic drivers of variability by focussing on the role of the global oceans and large scale atmospheric circulation patterns. Results indicate that variability in Okavango river flow is the result of a complex set of time-varying climate processes operating at different timescales. The very highest frequency component of Okavango River flow variability (less than 4 years) is negatively associated with Sea Surface Temperatures (SSTs) over the equatorial Atlantic during the early austral summer period. This is consistent with behaviour of the Atlantic Nino II mode of ocean variability and associated precipitation variability over the adjacent African continent. The influence of this mode has, however, declined in recent decades. In addition, individual Benguela Nino warm events can result in increased river discharge, as in 2004, but the relationship is inconsistent. Generally, low flow years tend to associate with an anomalous westerly circulation around a strengthened Angola Low, which reduces moisture transport from the east, thereby limiting convective rainfall over the basin. This is particularly apparent during the dry 1990s. Lower frequency variability at multi-annual timescales (~3-8 yrs) has a weak association with SST patterns characteristic of the El Nino/Southern Oscillation (ENSO) phenomenon, such that ENSO warm events weakly associate with low river flow, consistent with most of the rest of Southern Africa. There is evidence of lower frequency variability in the Okavango river flow but the short record renders robust analysis of these timescales problematic. The lowest frequency cycle with a period of about 60 years (not statistically significant) is out of phase with the Atlantic Multidecadal Oscillation (AMO), known to influence rainfall over the Sahel and Northeast Brazil, and lags the Pacific Decadal Oscillation by about 5 years. Overall, the absence of a clear, dominant control on river flow is partly the result of the location of the river basin, which straddles a sharp rainfall gradient, under the influence of both the Atlantic and Indian oceans which exhibit independent patterns of variability as well as modulation from the Pacific sector. Paucity of observational data over the region limits analysis that can be done.
Keywords: Okavango River, climate, variability, ENSO, decadal, cyclicity

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Restoration of Flood Pulsing and Wet Prairie on the Kissimmee River floodplain
Toth L. A., van der Valk A. G.

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The Kissimmee River in central Florida, USA, historically had a seasonal flooding cycle caused by summer rains. During the late summer and early fall standing water normally covered all of its floodplain. The Kissimmee was channelized in the 1970s and most of its floodplain was converted to improved cattle pasture and some areas to sod farms. A project to restore the Kissimmee River began in 1999 and is ongoing. Its many goals are dependent on the reestablishment of the historic pulsed hydrology of the river, which is expected to drive the restoration of the 3 dominant, pre-channelization vegetation types (wetland shrub, broadleaf marsh, and wet prairie) on the floodplain. Whether the full amplitude of the flood pulse on the Kissimmee has been restored can best be evaluated by assessing the extent to which historic hydroperiods and water depths have reestablished along the peripheral (highest) elevations of the floodplain where wet prairie vegetation was found prior to channelization, and by examining if the historic vegetation characteristics of this zone, wet prairie, has become re-established. Specifically, we examined how successfully the pulsed hydrology of the Kissimmee has been restored by comparing post-restoration (2001-2009) and pre-channelization hydroperiods and water depths, and by evaluating the composition of pre- and post- restoration richness and diversity of obligate and facultative wetland plant species in permanent quadrats in areas that had been historically wet prairie. We also investigated various potential sources of propagules (relict wetlands, seed banks, and several surrogates for hydrochory) of 5 indicator species of wet prairie vegetation to determine how dependent the restoration of wet prairie is on dispersal of propagules by flood pulses. Based on binomial logistic regressions, the presence of relict wetlands and surrogates for flooding (relative elevation, total days flooded) were the best predictors of the presence or absence of most of these indicator species in the permanent quadrats prior to and at the onset of restoration. The restoration of flood pulsing quickly initiated the re-establishment of wet prairie indicator species on the floodplain. However, reestablishment of characteristics of this community has been impeded by the presence of several exotic grass species, particularly limpograss, Hemarthria altissima, which had been introduced as cattle forage on the channelized floodplain
Keywords: restoration, seed banks, floodplain, relict wetlands, hydrology

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The influence of the duration of flooding on the spatial distribution of soil chemicals in the Nxaraga Lagoon floodplains, Okavango Delta
Tsheboeng G., Bonyongo C., Murray-Hudson M.

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The livelihood value of the natural resources of the Okavango Delta, Botswana, and implications of changes in environmental flows and management
Turpie J.K., Barnes J.I., Buzwani B., Nherera B., Arntzen J.

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Communities living around the Okavango Delta vary in terms of their access to services, grazing and farming areas, markets, and natural resources. This study aimed to quantify the overall use and value of wetland resources used by households living within range of the delta, and to compare this in different areas in relation to both biophysical and socioeconomic characteristics of the different zones. Social surveys were carried out in five zones within the Okavango Delta Ramsar Site – around the North, West, South West and South East margins of the delta as well as in the Central delta area. Households were typically fairly large, with an average of 7.2 to 8.3 people per household in the different zones. About 21-34% of adults were formally employed, with tourism and DWNP accounting for a large proportion of jobs, particularly in the central zone (60%) and South East zone (19%). Households had 3 to 4 dwellings on average, of which 20 – 49% were built with modern materials. Most households rely on paraffin for lighting and firewood for cooking. 75% of households were engaged in agriculture, and households with access to molapo fields had considerably higher rates of production. Livestock tended to be kept away from the wetland at cattle posts, where they are less susceptible to disease and cause less damage to crops. A large number of natural resources was harvested in the Ramsar site, many of these being used by a high proportion of households in each area. These included an estimated 76 million bundles of firewood, 280 tonnes of wild plant foods, 160 tonnes of wild meat, 450 tonnes of fish, some 276 000 poles, 150 000 bundles of reeds, 174 000 bundles of grass, 2300 bundles of papyrus, and 9000 bundles of palm leaves. Numerous products were also produced from natural materials. Medicinal plant use was significant but relatively uncommon, and timber, pottery and honey harvesting/production were uncommon. Agriculture and natural resource-based activities generated a total net value of over P95 million to households in the study area, of which over P16 million (17%) was attributed to the wetland. Variation in the use and value of wetland resources between the five zones was explained in terms of factors such as availability of resources, household income and access to markets. Based on a simple scenario analysis, changes in environmental flow and management of the delta were found to have potentially important impacts on the welfare of people living around the delta.
Keywords: wetland valuation; livelihoods; natural resource use; poverty; environmental flows

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Wildlife and birds in the Angola section of the of the Cubango river basin: bio-indicators for an ecosystem approach to management
Van-Dúnem dos Santos C.

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Changing resource use along flood pulsed ephemeral rivers: the case of Boteti River, Botswana
Vanderpost C.H.M., Ringrose S.M.

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Managing aquatic systems for biodiversity at transboundary catchment scale: the Kruger Park rivers example in South Africa
Venter F J

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Six major rivers flow in an easterly direction through the Kruger National Park (KNP). All these rivers originate in the Great Escarpment areas outside and to the west of the KNP and are highly utilized. They are crucially important for the conservation of the unique natural environments of the KNP. To the east and downstream of the KNP they flow over the coastal plains of Mozambique where they serve as critical resources for livelihoods and economic development before feeding important estuaries and flowing into the Indian Ocean on the east coast of Mozambique. The human population growth in the Lowveld during the past three decades brought with it the rapid expansion of irrigation farming, exotic afforestation and land grazed by domestic stock, as well as the establishment of towns, large unplanned informal settlements, mines, dams and industries. Along with these developments came overgrazing, erosion, over-utilization and pollution of rivers, as well as clearing of indigenous forests from large areas outside the borders of the KNP. Poor governance and mismanagement of sewerage systems in the upstream areas and the need from a neighbouring country downstream to develop and support its economic growth provides added challenges. All these developments have an impact on the KNP rivers and cause great difficulty in the conservation of these ecosystems and serious challenges to the KNP's management The South African National Parks (SANParks) has an ecosystems approach towards conservation aiming at conserving biotic diversity through the conservation of natural habitats and processes. The decade-long Kruger National Park Rivers Research Programme provided the scientific base for the proper management of the rivers as well as mustering much needed scientific, social and political support. The Management of these rivers often extends into the socio-political realm and requires negotiation skills over and above normal conservation management skills. Management actions which have been taken or are ongoing as well as their results are discussed and solutions to certain problems proposed.
Keywords: River management, Kruger National Park

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Floodplain as a critical element of a system solution for water quality management: UNESCO Pilica River Demonstration Project in Ecohydrology, Poland
Wagner I., Kiedrzyńska E., Izydorczyk K., Zalewski M.

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Understanding of interrelationships between ecological processes and the water cycle in a catchment scale and ecosystem processes regulation is a foundation for the ecohydrology concept. It allows for enhancing the absorbing capacity at critical areas of a catchment (opportunities) against anthropogenic impacts (threats), in order to enhance the overall catchment resilience. Identification of chances and opportunities provides a framework for development of stem solutions in ecohydrology. Natural river floodplains, due to their pulsing character of water, energy and matter flows, are highly diversified, productive and resilient areas. They provide a number of ecosystem services if linked with adjacent terrestrial ecosystems, as well as social, cultural and economical systems. These characteristics, as well as buffering location at the transition between terrestrial and water ecosystems, makes them one of the critical elements in system solutions for water quality management. The first effort towards implementation of ecohydrology for water quality problems was undertaken at the UNESCO IHP Demonstration Project on the Pilica River (Poland). The research and implementation programme including the river, its floodplains and a lowland reservoir aimed at mitigating the health hazard resulting from toxic cyanobacterial blooms, and contributing to reestablishing tourist-based economy in the region. The research started with an analysis of the dynamics of the chemical composition of waters of the Pilica River on the background of its hydrological pattern. It allowed for identification of the episodes of high reservoir nutrient loading and the hierarchy of factors determining its dynamics. Floodplains were considered to be the tools to reduce the reservoir supply by their inundating with the waters of the nutrient-condensed stages. The research continued with an assessment of the floodplain capacity for retention of matter load transported by the river by sedimentation and assimilation in the biomass, depending on hydroperiod. The results from the experimental floodplain together with the GIS-based digital terrain model and hydraulic model were used for calculation of sedimentation in a 30-km upstream-reservoir section of the river valley. This research contributed to development of a systems solution for water quality improvement in the Pilica catchment, and is been constantly updated, following the idea of an Adaptive Assessment Management approach. The developed solution contributes to fulfilment of Poland's obligations to comply with European Water Framework Directive.
Keywords: ecohydrology, ecosystem services, system solution, UNESCO IHP, water quality, nutrients trapping

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Wetland rehabilitation and acid sulfate soils: Implications for water quality and management, New South Wales, Australia
White N.S.

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Acid sulfate soils (ASS) occur both in coastal and inland regions throughout the world, but are more common in coastal wetland environments. These soils formed thousands of years ago and were subject to a natural wetting and drying cycle. Associated with this process would have been the oxidation and subsequent release of sulfuric acid and heavy metals, such as aluminium and iron, into the groundwater and nearby surface water during high rainfall. However, constructed drainage in wetlands to increase available agricultural land has severely altered this wetting and drying cycle, causing acid and salt scalds, reduced water quality, and negative ecological impacts. Management of degraded ASS wetlands, particularly in the coastal zone of Australia, often involves retaining water on the floodplain to reduce the impact of the flood pulse on water quality and downstream habitats. Little Broadwater, located on the Clarence River floodplain, northeastern New South Wales, Australia, was a typical drained wetland affected by oxidised ASS. In mid-2003 an in-drain water retention structure was installed, and controlled tidal exchange was restored to the wetland to initiate rehabilitation. Initially the wetland was managed with saline exchange, but was later changed to seasonal/adaptive freshwater management. Monitoring of water quality in Little Broadwater was conducted from 2005 to 2007. The aim of the study was to examine the spatio-temporal variation in water quality, and to assess the effectiveness of seasonal/adaptive management on reducing the discharge of acidic water during the wet season. During the first year of the study, desiccation of the wetland resulted in salinisation and scalding of the wetland in spring, and acidic water being released into the adjacent creek with the onset of summer rainfall. However, the duration and severity of the acid flux was reduced from an average pH of 4 which lasted 3 months during pre-rehabilitation conditions, to an average pH of 5.5 which lasted only 2 weeks. Within-wetland water quality remained relatively poor in some regions for a period of at least 8 months, due to the reduced natural flushing of the wetland. Conversely, during the second year of the study, no scalds were observed and an acid flux over the wet season was not recorded. This was attributed to higher winter rainfall, which allowed for maintenance of surface water cover and thus reduced the oxidation of ASS. The results of the study emphasise the importance of maintaining water cover during the drier winter and spring to reduce the salinisation of the wetland, and prevent oxidation of ASS and the consequent pulse of acid water. The development of a conceptual model of wetland functioning indicated the range and complexity of factors which affect water quality, with climate identified as one of the main driving components. The successful management of ASS wetlands, especially those under agricultural land use, is therefore highly dependent on climatic conditions and the ability to adapt management of the wetland to these conditions.
Keywords: Acid sulfate soil, rehabilitation coastal floodplain, water quality, wetland, management

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Cattle, sugar and wetlands : Maintaining livelihoods while restoring the flood pulse in the Clarence River Floodplain, Northeast New South Wales, Australia
White N.S., Smith A.N., Wilson P.R.

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Livelihoods need to be maintained during ecological restoration. Since 1997, ongoing restoration of the Clarence River floodplain (north-east New South Wales, Australia), following historical drainage of wetlands, has addressed loss of habitat, poor water quality, acid sulfate soils, and in some instances, decreased agricultural productivity. Incorporating agricultural livelihoods into management, particularly beef cattle and sugar production, has been important for sustaining environmental outcomes. From 2005 to 2007 detailed hydrological research was carried out, and considered against the restoration achievements of the Clarence Floodplain Project. The spatio-temporal variability of hydrology and habitat within various wetlands was examined to identify how restoring wetland function affected livelihoods and vice-versa. Improved management of flow control structures, in cooperation with landholders, and negotiated in formal drain-management plans, resulted in excellent long term environmental outcomes including amelioration of the effects of acid sulfate soils, increased fish passage and biodiversity, and the retention of water on land for longer periods. However, sugar cane land could not be flooded and restoration there was limited to increasing water exchange in the associated drainage network. Meanwhile, cattle graziers had mixed attitudes to restoring the flood pulse to their lands, with some more accepting than others. Land recently designated for conservation purposes, and where management is not dependent on individuals’ livelihoods, is being guided by current research. The flood pulse resulted in significant temporal variation in water quality, although seasonal patterns were often not clearly discernible due to variable climatic conditions. Spatial and temporal hydrological and ecological attributes of wetlands changed between years. At one wetland, Little Broadwater, one year was characterised by dry conditions, reduced water cover (which was highly saline), bare mud flats devoid of vegetation, acid scalds, and few waterbirds. Over the summer period during the flood pulse, freshwater (and acid-tolerant) marsh vegetation appeared. However, due to the oxidation of acid sulfate soils during the dry period, water quality was severely degraded due to the very high metal concentrations and low pH of the water. Persistent fresh conditions during the second year of the study resulted in improved water quality and high density growth of wet pasture species (Eleocharis equisetina and Paspalum distichum) providing benefits for cattle and waterbirds. Seasonal freshwater influx is vital in restoring the functioning of coastal floodplain wetlands and can provide benefits for habitat and agriculture. An adaptive management approach is required that is active and ongoing with the regional coordination of site-specific plans that can respond to individual circumstances, changing restoration imperatives, and changing funding opportunities.
Keywords: Clarence River, wetlands, restoration, livelihoods, Australia

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A Review of Research on Molapo Farming in the Okavango Delta
Wiles G.C.

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Flood-recession farming is practised along many rivers of the world. In Botswana this farming practice, commonly known as molapo (plural melapo) farming, is practised in Ngamiland District in the northern part of the country. Molapo farming is dependent on flooding resulting from water inflows into the Okavango Delta. Water enters the delta at Mohembo with flows peaking in April and declining to their lowest level in November. The floods reach the lower end of the Okavango Delta in June/July and recede from August onwards. The floodwater inundates low lying flood plains in the lower part of the delta. Molapo farming is mainly concentrated in the southeastern fringe of the delta (Boro-Shorobe floodplain) and in the western delta (Gumare-Nokaneng area). Between September and December, depending on that year’s flooding regime, seasonally flooded areas become ready for cultivation. The relatively fertile and heavier soil of the molapo basins and the soil moisture retained after the flood, plus the onset of the rainy season that usually commences in November, make Molapo farming more attractive than dry land farming. In the Gumare area a development project conducted research on molapo farming from 1981 to 1986. The project concluded that molapo farming has high potential yields but these are frequently not realised due to a number of risks. The main risks were listed as: damage by livestock, damage by crop pests, poor germination, drought and flooding. It was estimated that only 25% of planted fields resulted in successful crops. Agronomic techniques to improve production in the molapo farming system were evaluated. Research on molapo farming in the Shorobe area was carried out by another development project from 1984 to 1992. The extent of the area available for flood recession cultivation at different flooding levels was established and flood control structures were put in place to control water flow into the cultivated melapo areas. The main constraints to successful molapo farming were investigated and agronomic trials were conducted to address these constraints. It was established that flooding in the Shorobe melapo is mainly the result of backflow in the Thamalakane, and construction of a ’master bund’ across the Thamalakane was proposed to try and improve the reliability of this flow.The area of land under molapo farming declined substantially since the 1960s mainly due to reduction in river flows. The Thaoge system in western Ngamiland has been drying out due to river blockages and a shift in flows towards the Jao/Boro system. Areas that were historically cultivated by flood recession farming in the Gumare-Nokaneng area are no longer flooded. In the Shorobe area there was a sharp decline in areas under molapo farming from 4881 ha in 1967 to only 555 ha in 1989. The very low flows experienced in the Boro River from 1993 to 2003 further restricted the practice of molapo farming in the southeastern delta. The main findings of two development projects designed to address constraints to molapo farming are summarised and the future of molapo farming in the Okavango delta in the light of changing flood patterns is discussed.
Keywords: flood recession farming, Okavango Delta, agricultural development

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Floodplain fish assemblages and flow-pulse responses in a regulated dryland river system, Australia
Wilson G.G., Bickel T.O., Sisson J.L.

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Floodplain river systems across Australia’s northern Murray-Darling Basin are among the most hydrologically variable globally, although most now receive a significant portion of their discharge through regulated water resource development schemes. Terminal wetland complexes are a prominent ecological feature of these floodplain rivers, and are gaining increasing recognition for their high conservation value and ecological role at catchment and landscape scales. However, many terminal wetlands are located in or downstream of significant agricultural landscapes. While the resulting alteration of natural flooding patterns has led to legislated environmental water provisions, terminal wetlands are one of the most difficult points in a catchment to which to deliver managed flow releases. Moreover, managers of these systems need clear guidelines as to how various ecosystem components respond to flow variability in order to make effective environmental release decisions. The Lower Gwydir wetland ecosystem in north-west New South Wales is a large (though reduced) terminal wetland that includes a number of privately-managed Ramsar sites. Environmental water releases from the upstream Copeton Dam have been made into these wetlands for over 14 years. This study considered a mix of ecological data and management responses to assess the effectiveness of recent environmental water (or ‘Environmental Contingency Allowance’, ECA) releases. We used an event-based sampling schedule and fyke-net methods from 2006 to 2009 to monitor responses of fishes to environmental water and other flows in floodplain channels throughout this wetland system. Interannual recruitment was sporadic over the study interval, and relationships with annual discharge were unclear. At the flow pulse scale of days to weeks, recruitment responses were apparent following some environmental releases, although these were inconsistent in both time and space. Conversely, consistent spatial patterns in assemblage structure were clearer, both within and between channels. In particular, upstream reaches appeared to function as key spatial refugia for a number of rarer species, while generalist dryland river species were often more abundant downstream. Collectively, these patterns suggest that structural habitat characteristics may modify or override any influences of flow variability at the reach (10 km) scale. Careful monitoring designs are needed to detect temporal patterns in regulated dryland rivers, where discharge and biotic characteristics are highly variable. These should account for the multitude of flow uses and delivery points and any spatial differences in assemblage structure. Options include event-based only schedules; routine monitoring of at least quarterly (seasonal) intervals, or a mix of these strategies. Establishing conceptual models beforehand of the lifehistory of key species, along with the collection of baseline data sets of 2–3 years minimum, will greatly enhance the capacity to underpin future flow-management decisions.
Keywords: fish, dryland rivers, flow variability, Lower Gwydir, Murray-Darling Basin

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Measuring Information Flows to Better Understand Governance of Water and Wildlife Resources
Wojcik D. J.

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Communication and information flows are of critical importance to the governance and management of natural resources in flood pulsed wetlands. This interdisciplinary research is based upon the premise that in order to understand and improve governance, it is necessary to investigate what information is available, how information is disseminated and received (through both formal and informal modalities), and how that information is integrated into people’s perceptions and decisions. This presentation specifically addresses information flows about water and wildlife resources in villages participating in community-based natural resource management (CBNRM) in the Okavango Delta region of Botswana. While there are national government ministries that influence the management of both water and wildlife resources in Botswana, communication around these resources differs. Decisions about water are often made at the micro scale, with information exchanged within households and family groups. In contrast, wildlife resources are managed at the community level, with information disseminated through CBNRM governance structures. The investigation of variables affecting information flows can contribute to more effective communication strategies about the resources themselves, as well as people’s rights with regard to these resources. The primary method used in this study is social network analysis. This approach is used to explore how people are connected and exchange information within and beyond their communities. Respondents are asked to name individuals with whom they communicate on a regular basis. They are then asked several questions about each person named, including the extent to which they have received information from that person about natural resources (water and wildlife), CBNRM programs, community leadership and decisions, and national government programs. These data are analyzed using EgoNet personal network analysis software, with resulting statistical outputs and visualizations used to generate interview questions specific to each respondent’s network. Both these individual networks and composite networks for each village reveal important opportunities and challenges to natural resource governance, including elite capture of information and unlinked community members. The dynamic nature of both the biophysical and socio-cultural environments of flood pulsed wetlands in which natural resource decisions are made requires that communication strategies focus on being adaptive and responsive to changes and uncertainties inherent in these complex systems. This research makes theoretical and practical contributions to the study of information flows, governance, natural resource management, decision-making, and adaptive capacity. It also contributes methodologically, as social network analysis has not been widely applied to natural resource management, rural settings, and the southern African context. This study is particularly important in light of climate change threats, which have the potential to greatly affect this region’s water resources and in turn human health, agriculture and food security, wildlife and ecosystems, tourism, and livelihoods. Specific to CBNRM, this research is valuable to district and national level planners seeking to make improvements to communication strategies and best support the development of locally-based resource management initiatives. Understanding the communicative connections among people provides vital information about how individuals can learn from others, become empowered through enhanced communication, build adaptive capacity for greater socio-ecological resilience, and ultimately make more informed decisions.
Keywords: Information, Communication, Water, Wildlife, Natural resource governance, Community-based natural resource management, Okavango Delta, Botswana

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Multidecadal flood pulsing in the Okavango Delta in the past and under changing climate
Wolski P., Todd M.

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Carbon and water fluxes in the Okavango Delta, Botswana
Wolski P., Murray-Hudson M.A., Mosimanyana E.

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Understanding of factors affecting biogeochemical processes in tropical and subtropical wetlands is relatively limited. In the Okavango Delta, measurements of ecosystem productivity and water fluxes are scarce, particularly at the landscape spatial scale. In order to improve the quantitative understanding of ecosystem biogeochemical processes for vegetation assemblages associated with various hydroperiod conditions in the Okavango Delta, carbon and water fluxes were measured using the eddy-covariance method during four seasons at five sites within the Okavango Delta. The sites represent the hydro-ecological types prevalent in the system: permanent swamp dominated by Cyperus papyrus, permanent swamp dominated by Miscanthus junceus, a long-hydroperiod floodplain dominated by sedges such as Eleocharis dulcis, a short hydroperiod floodplain dominated by Panicum repens, and an open water lake. Maximum net ecosystem exchange for vegetated sites varied between -1 and -14 μmol m² s^-1. While high values were consistently observed at the Cyperus papyrus site, the short-hydroperiod site had the highest recorded rate, but only during the rainy season, after the flood has receded. Evapotranspiration fluxes reaching 7 mm day^-1 in summer and 3 mm day^-1 in winter were recorded, with maximum hourly rates corresponding to 0.6-0.9 of the reference crop evapotranspiration obtained from meteorological data. Lake measurements revealed consistent emission of CO₂ (nighttime and daytime, and for all seasons), with rates reaching 2 μmol m² s^-1, and evaporation varying between 1 and 8 mm day^-1. Based on the measured fluxes, biomass and nutrient contents of vegetation at the measurement sites, factors that affect inter-site and inter-season differences in net ecosystem exchange and evapotranspiration are formulated. The results of this study form the basis for improving the understanding of biological productivity at the ecotope level and improving our understanding of the system’s hydrological variability. This will therefore assist in the development of ecosystem models that predict carbon and water cycling in wetland systems following climate change.
Keywords: eddy covariance, net ecosystem exchange, evapotranspiration, floodplain, lake

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Floodplain declaration: Translation of floodplain ecohydrology into a policy framework
Zalewski M

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In the face of dramatic acceleration of global environmental degradation, and a progressive shortage of water and energy, there is increasing scientific evidence that the Biogeosphere is a self- stabilizing system controlled by feedback mechanisms among climate, water, and biota that has developed during the Earth's evolution. In Anthropocene the natural homeostatic regulation of hydrological and biogeochemical processes has been dramatically reduced, resulting in a decline in biodiversity and ecosystem services. River valleys and floodplains which occupy lower elevations in the landscape are highly exposed to this cumulative and still increasing human impacts from the surrounding catchment. At the same time, floodplains, as dynamic wetlands and integral part of river basins, have high potential to mitigate environmental change and resulting threats for humans. This is due to their exceptional capacity for water retention, stabilization of hydrological patters and flood mitigation, biological production and biodiversity maintenance, groundwater recharge, river purification and regulation of nutrients exchange between land and water, high compensatory food production, CO₂ sequestration and production of bio-fuels, and other ecosystem services, all maintained by the pulse-regulated hydrology of running waters. This makes them important components of global environmental security and resilience. In order to reverse floodplain degradation and increase the ecological resilience and economic benefits in catchments, a shift in strategy from floodplain exploitation to floodplain sustainable use is necessary. Accordingly we need a change of public perception from sectoral, structural and reactive responses to integrated, process-regulation-oriented and proactive approaches. Achieving of this goal may be possible due to: i) ecohydrological management based on "dual regulation" and harmonization of biodiversity conservation with human needs, such as flood mitigation, food and energy production, transport and recreation; ii) harmonization of hydrotechnical infrastructure operational instructions with catchment scale ecosystem processes; iii) consideration of the cultural heritage of the catchment as an important element for spatial reconnection of floodplains to the adjacent landscape, as well as restoration of links to social, economic and cultural values; and iv) shaping people's perception and attitudes to the changing environment based on integrative science which depend on development of programs and methodologies for education and communication. Following this idea, a “Declaration on Sustainable Floodplain Management” (“Floodplain declaration”) was developed by the International Conference on Ecohydrological Processes and Sustainable Floodplain Management in Lodz, Poland (May 2008). The declaration proposes using ecohydrology - a holistic problem-solving concept - for floodplain sustainable management. Applying ecohydrology-based system approaches and foresight and learning alliances methodologies should increase the resilience of catchment and freshwater resources, enhance ecosystem services, and improve human health and the quality of life following the UN MDGs.
Keywords: ecohydrology, floodplain management, floodplain declaration, policy

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Landscape change in flooded wetlands: a case study of Xianghai Natural Reserve, Northeastern China
Zhang M., Cui L.

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Xianghai Wetland, located in semi-aird western Jilin province in north-eastern China was approved as a national natural reserve in 1986 and designated as a Wetland of International Importance (Ramsar site) in 1992. Xianghai Wetland Nature Reserve covers 10.54*10⁴ ha and includes marshes, lakes, ponds, swamps, meadows, reservoirs, other landforms such as sand dunes, saline and alkaline areas as well as plantations and cultivated land. Most lakes and marshlands are formed due to the overflow of the trivers Huolin River, Emutai River and Yaoer River. Xianghai Natural Reserve is an important winter-stop and breeding area for, rare and endangered water birds such as the red-crowned crane (Grus japonensis). Rare plant species including the Mongolian yellow elm (Ulmus macrocarpa var. mongolica) are found in the Reserve and therefore are protected. In 1998, Xianghai Natural Reserve suffered catastrophic flooding that was followed by a 10 years drought. Using topographic maps, LANDSAT TM and EOS MODIS images and applying Remote Sensing (RS) and the spatial analysis techniques of Geography Information System (GIS), and capplying landscape ecology theory, the effect of flooding on landscape change before and after 1998 was analyzed. The analysis examined changes in area extent, and spatial and pattern distribution of wetlands and other landscapes. After analyzing the change process, pattern indexes and transition processes of the landforms at different stages, the dynamic nature of wetland change was revealed. Large saline and alkaline land, fresh-water marshes and meadows were transformed to river and lake wetlands following the 1998 extraordinary flood, while large area of meadows and saline and alkaline lands were changed into marsh wetlands. The extent of these two kinds of natural wetlands was enlarged, their fragmentation was reduced and their integrity was increased. This shows that flooding played an active ecological role in regenerating the degraded wetland.
Keywords: northeastern China, Xianghai wetlands, landscape change, flooded plain

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