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No description available.

The Alfred Bog wetland is the largest high quality bog ecosystem and one of the most important natural areas in southern Ontario. The 4,200 hectare bog provides habitat to a large number of rare and endangered species and plays an integral role as a natural water filter. This study used the contingent valuation survey method to estimate respondents' willingness to pay for the preservation of the Alfred Bog wetland, which is threatened by the competing activities of drainage, burning, and the extraction of peat. A multiple bounded discrete choice model was used to analyze the survey results. Results indicated that respondents were willing to pay an average of $79.22, in the form of a one-time voluntary contribution to a hypothetical preservation fund, for the preservation of the Alfred Bog wetland. Conservation club membership, visits to the bog, donations to wetland preservation programs, attitudes, distance from the bog, household income, and education level were found to be important predictors of willingness to pay. Aggregate willingness to pay to preserve the bog was estimated to be between $2.2 million to $663,000 depending upon the inclusion or exclusion of protest bids. The survey results suggested that most of this value was nonuse value attributed to option, bequest, and altruistic values. Thus, the failure of policy makers and resource managers to consider nonuse values in decision making processes can understate the value of preserving the Alfred Bog.

Wetlands have long been recognised as enhancing the quality of inflowing waters, particularly regarding the plant macronutrients nitrogen and phosphorus. Any research into non-limiting solutes has largely been of a 'black box' nature, with no insights into mechanism of retention presented. Research in the Okavango Delta, Botswana and preliminary work in the uMkhuze Wetland System, South Africa has identified retention of large amounts of non-limiting solutes within these wetland systems. Chemical sedimentation in the Okavango accounts for 360 000 tonnes per year, while a rough mass balance in the uMkhuze Wetland System suggested retention on a scale of 16 000 tonnes per year. The Yengweni and Totweni Drainage Lines are north-south oriented systems that, together with the uMkhuze River floodplain, were selected to investigate chemical retention in the uMkhuze Wetland System. These drainage lines were once tributaries of the uMkhuze River that have been dammed at their southern ends by alluvial deposition on the uMkhuze River floodplain to form tributary valley lakes. Considering seasonal variations in groundwater levels in combination with conductivity, sites of solute concentration were revealed in the groundwater. The use of chloride as a concentration tracer has indicated that solutes are progressively depleted in the groundwater under the influence of a concentration mechanism, with silicate minerals and calcite attaining saturation. Groundwater chemistry and hydrological factors have highlighted the southern Yengweni and floodplain regions as active sites of solute concentration. In these areas, groundwater elevations are variable, which is mirrored by variation in groundwater chemistry. Although elevated solute concentrations do occur elsewhere, the seasonal variation is less marked. The search for solute sinks in the uMkhuze Wetland System also considered the sediment of the wetland system as a possible sink. Elevated solute concentrations in the groundwater could be linked to the accumulation of minerals in the soil, suggesting precipitation of minerals by saturation under a concentration process. In tho southern Yengweni and floodplain regions, concentrated groundwater bodies were linked to high concentrations of minerals in the soil, including neoformed montmorillonite, and calcite deposits. Other sites of chemical concentration in the groundwater in the northern Yengweni and Totweni Drainage Lines have produced little modification of the reworked marine sands on which the wetland is founded. Processes in the southern Yengweni and floodplain regions are clearly more efficient in removing solutes from the wetland surface water and immobilising them in the soil of the drainage line than is happening in the Totweni and northern Yengweni regions. Transpiration by vegetation seems to be the major factor driving chemical sedimentation in this subtropical system, and as such vegetation in this wetland system is not the passive factor it is often assumed to be. The vegetation of the wetland is itself initiating and perpetuating the retention of chemicals in the system. Hierarchical patch dynamics in combination with the theory of thresholds, derived from geomorphology, is useful for placing chemical sedimentation in wetlands into a spatiotemporal framework that increases understanding of the process, and allows identification of sites where chemical sedimentation is likely to occur in wetlands. There are a number of thresholds that define chemical sedimentation driven by evapotranspiration in the uMkhuze Wetland System, which may be considered at increasing spatiotemporal scales from the microscale of seconds within a limited section of the groundwater, to the macroscale thousands of years at the landscape scale of the wetland system. With increasing scale, the effects of the transformations at each hierarchical level have corresponding increasing influence on the structure and function of the wetland system. The initial threshold is surpassed once concentration products of evapotranspiration are retained to some degree within the wetland system, due to increased residence times of groundwater on modification of the hydrological regime from discharge to recharge. Increased residence times allow the products of seasonal concentration to persist beyond the timescale of seasons. The second threshold is the saturation and precipitation of mineral phases that accumulate within the soil profile. With sufficient accumulation of chemical sediments, the physical properties of the sediment are modified, which reduces the velocity of water flow in the soil (Threshold 3). This has implications for hydrological flows between the surface water and groundwater systems. Threshold 4 is attained once the sediment is modified to such a degree that the chemical sediments act as an aquitard, such that surface water and groundwater may be effectively separated. Extrinsic factors influencing the process of chemical sedimentation, such as the atmospheric water demand, chemical composition and volume of inflowing waters, as well as the nature and density of vegetation, may indicate the potential of a system to sequester chemical sediments but cannot predict their occurrence completely, except maybe at the extremes of semi-arid and arid systems. It is the local and intrinsic factors of hydrological flows, their chemical composition and nature of clastic sediments that will govern residence times of water in the system, and therefore the location, nature and extent of chemical sedimentation. Furthermore, chemical sedimentation driven by evapotranspiration is not limited by sediment type as are adsorption and complexation reactions, which are dependent on the availability of active sites, nor by chemical composition of inflowing waters as this factor simply dictates the suite of minerals produced. Therefore, chemical sedimentation in wetlands is expected in a wide range of settings from temperate to arid, with varied substrates and hydrological regimes. The large-scale removal and retention of solutes within wetland soil has system-wide implications for wetland structure and functioning. The ramifications of chemical evolution of the groundwater and soil extend from influencing the distribution of plants and animals, to geomorphological implications of accumulating chemical sediments, as well as off-site effects including water quality enhancement of water available to downstream systems and users. An understanding of the process of chemical sedimentation in wetlands may inform good management to protect this vital function of wetlands, particularly with increasing development and industrialisation pressures in many areas. Extensive chemical sedimentation has been discovered in both the Okavango Delta, Botswana by Ellery, McCarthy and colleagues and through this study in the uMkhuze Wetland System, with the proposed driving force being transpiration. Vegetation induced chemical sedimentation is a hitherto unknown, although seemingly important component, of chemical processing in tropical and subtropical wetlands, and under certain conditions, even in temperate wetlands. This insight into chemical transformations in wetland systems adds a further dimension to the accepted model of chemical cycling. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2008.

Tarebia granifera is a prosobranch freshwater gastropod from south-east Asia which has invaded other sub-tropical parts of the world. This snail has recently also invaded the iSimangaliso Wetland Park, often reaching population densities of over 20000 ind.mˉ2 and dominating benthic invertebrate communities. A multiple method approach was used to address several aspects of the biology and ecology of this non-native invasive species (NIS). The tolerance of T. granifera to salinity and temperature was investigated through the experimental manipulation of these factors. T. granifera survived exposure to temperatures between 0 ºC and 47.5 ºC. More remarkably, this snail was able to survive a salinity of 30 for 65 - 75 days. Population density and size structure were monitored in estuaries and coastal lakes. T. granifera successfully invaded estuaries despite frequent exposure to high salinity and desiccation. The persistence of T. granifera was largely ensured due to the wider environmental tolerance of adults (20 - 30 mm shell height) which carried an average of 158 ± 12.8 SD brooded juveniles. Multiple introductions were not essential for the success of this parthenogenetic NIS. Using gut fluorescence and carbon budget techniques it was estimated that T. granifera consumes 0.5 - 35% of the total available microphytobenthic biomass per day, or 1.2 - 68% of the daily primary benthic production. The carbon component estimated from the gut fluorescence technique contributed 8.7 - 40.9% of the total gut organic carbon content. A stable isotope mixing model was used together with gut content analysis to estimate the diet of T. granifera and dominant native gastropod species, potentially competing for resources. Results were used in the formulation of an index of isotopic dietary overlap (IDO, %). This approach yielded detailed information both on general changes in ecosystem functioning and specific species interactions. Before/After-Control/Impact (BACI) logic was used in a multivariate approach to separate human perturbations from natural spatio-temporal variability displayed by communities, and to further separate perturbations due to NIS. Human intensification of drought negatively affected biodiversity and T. granifera may exacerbate this problem by displacing native species from critical refugia and contributing towards biotic homogenization. The present findings constitute a contribution to the scientific knowledge on biological invasions and a useful tool towards adaptive management in the iSimangaliso Park. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

Hlatikulu Vlei, situated in the foothills of the Natal Drakensberg, is one of the priority wetlands in KwaZulu-Natal, occupying an area of 733 Hectares. The importance of Hlatikulu Vlei lies in its functions to store water, regulate stream flow and attenuate floods, as well as to provide suitable habitat for wildlife and grazing for livestock. Hlatikulu Vlei is a threatened system and has suffered the effects of human mismanagement. Forty-nine percent of the vlei has been classified as disturbed or destroyed, mainly due to the construction of two large dams and past drainage of vlei to facilitate pasture planting. The effects of grazing and fire on the plant communities has been considerably less. Vegetation communities at Hlatikulu Vlei have similarities with those at Ntabamhlope Vlei. The main plant communities present at Hlatikulu Vlei are: vlei grassland, sege-meadows, bulrushes and reedswamp. Species compositions of the mixed sedge and grass sedge-meadow community have a notably higher species diversity than similar communities sampled at Ntabamhlope Vlei and the mires at Highmoor. Soil type and moisture content are shown to be the most significant environmental factors determining the distribution of plant communities and species within the vlei. A wetland re-establishment and rehabilitation programme in the Hlatikulu Crane and Wetland Sanctuary has been effective in allowing many wetland plants to become reestablished. The sanctuary communities bear greater similarity to the sedge and rush sedge-meadow community, than the mixed sedge and grass sedge-meadow communities that were originally present. This is also reflected in the seed bank. All three Southern African crane species (Blue, Wattled and Crowned Crane) and fourteen species of waterfowl have been recorded in the Hlatikulu Crane and Wetland Sanctuary since the wetland rehabilitation programme. The waterfowl play a role in the dispersal of seeds into the sanctuary, particularly those of Schoenoplectus decipiens and Eleocharis dregeana and are in part responsible for the return of certain wetland plants to the sanctuary. The flooding of soils, the fluctuating water level and the soil type related to hummocks and to channels are shown to be responsible for the location of Cyperus denudatus, Arundinella nepalensis and Aristida junciformis in differing positions in the channels and on the hummocks and are also responsible for the maintenance and functioning of the hummocks and channels. Seed banks on the hummocks are similar to seed banks in the channels, however the extant vegetation on the hummocks is distinctly different to that in the channels. Certain species represented in the channel seed bank are being excluded from surviving to maturity. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.

Waterbird habitat in the Saskatchewan River Delta (SRD) has been altered by numerous upstream and downstream anthropogenic developments. Wetland water-level management has been used in an attempt to mitigate these changes, but the effects on the local waterbird community are unknown. Using an experimental approach, I examined the effects of wetland water-level management on waterfowl and marsh birds in the SRD. In 2007, three wetland basins in the Summerberry Marsh Complex, Manitoba were partially drawn down and paired with three additional wetlands managed with high water levels. In 2008-09, I surveyed waterfowl within the study wetlands during different life stages using point counts and aerial surveys. Abundances of breeding marsh birds, including American Bitterns, Least Bitterns, Soras, Virginia Rails, Yellow Rails, American Coots, and Pied-billed Grebes were estimated using call-response surveys. Generalized linear and generalized linear mixed models were used to determine relationships between relative bird abundances and the physical characteristics, vegetation characteristics, and forage fish and invertebrate abundances within the wetlands. Dabbler species of waterfowl preferred the partial drawdown wetlands during nearly all life stages, except brooding. Diver species preferred the non-drawdown wetlands, but only during the spring-breeding and fall-staging periods. Invertebrate abundance affected wetland use by dabbler and diver species, particularly during the spring-breeding and brooding periods. Subsequently, wetlands with high forage fish abundances were avoided. In the fall, dabbler densities on the partial drawdown wetlands increased from an average of 0.4 birds per hectare to 1.5 birds per hectare. This influx was likely due to the accessibility and availability of submerged aquatic vegetation. The partial water-level drawdowns did not benefit any species of marsh birds examined. American Bitterns, American Coots, and Pied-billed Grebes chose the deeper, non-drawdown wetlands, due to high abundances of forage fish. Vegetation interspersion, particularly that offered by Schoenoplectus, was preferred by these species. Soras and Virginia Rails were not affected by water depth or vegetation characteristics, but were positively correlated to invertebrate abundances. Subsequently, the Sora avoided wetlands with high forage fish abundance. The conditions created by the partial water-level drawdowns did not meet the requirements of all species present in the SRD. Therefore, future wetland management should focus on providing a wide range of water depths within wetland complexes to accommodate the requirements of different avian species.

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No description available.

Ecotourism is considered an effective agent to conserve environmentally fragile areas while bringing economic opportunities to local communities at the same time. In the past decades, empirical studies about ecotourism's conservation effects on wetland ecosystems attracted relatively less academic attention than rainforests and coral reefs. Florida, listed as one of the states with the greatest share of wetland loss in the U.S. due to rapid growth in agriculture, tourism, and urban development, has a small number of existing wetlands under the protection of the park and reserve system. To generate long-term positive environmental impacts, ecotourism stakeholders' contributions to planning and management activities could be an alternative beyond land use controls for conserving Florida wetlands. The major objective of this study is to explore the relationship between ecotourism and wetland conservation contributions which lead to long-term environmental sustainability. The study surveyed 97 nature-based tour operators in Florida on their activeness in a set of wetland planning and management behavior, the proportion of tourism revenue from ecotourism, and the perceived tourism benefits regarding economic, socio-cultural, and ecological aspects. Factor analysis was employed to identify indicators for the composite factors, such as the conservation contributions and incentives (i.e., economic benefits, socio-cultural benefits, and ecological benefits). The effects of ecotourism involvement and conservation incentives on tour operators' participation in wetland conservation practices were statistically modeled. The results demonstrated the business characteristics, degrees of the perceived tourism benefits, and frequency of participation in wetland conservation activities of responding tour operators. On average, tour operators were not as active in wetland management and planning approaches leading to the long-term environmental health as theories suggest they should be. Generally, the regression analysis results illustrated the significant association between ecotourism involvement and tour operators' conservation contribution. It is noteworthy that the effects of ecotourism involvement on tour operators' participation in environmental planning and water management processes were relatively important. In addition, the incentive of the perceived socio-cultural benefits was identified as the leading factor by regression analysis. The findings lent to the policy suggestions in expanding the incentives to drive major stakeholders' active engagement in wetland conservation planning and management, which is critical for collaborative and adaptive management.