Strategies for conserving migratory waterbirds; proceedings of Workshop 2 of the 2nd international conference on wetlands and development held in Dakar, Senegal, 8-14 November 1998 (original) (raw)
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Managing wetland habitats for waterbirds: an international perspective
Wetlands, 2010
The loss and degradation of wetlands worldwide has adversely affected waterbirds, which depend on wetland habitats. Many studies have indicated that effectively managed wetlands can provide alternative or complementary habitats for waterbirds and mitigate the adverse effects of wetland loss and degradation. We review the studies on the habitat variables affecting use of wetlands by waterbirds, and we suggest how wetlands can be managed to provide waterbird habitat. These habitat variables include water depth, water level fluctuation, vegetation, salinity, topography, food type, food accessibility, wetland size, and wetland connectivity. Overall, the practice of wetland management requires integrated knowledge related to the entire wetland ecosystem, and ecosystem-based approach is needed to improve the habitat quality of managed wetlands with considering multiple spatial scales, temporal variability, and trade-off among diverse habitat requirements of different waterbirds. Several priorities for future research and management are also suggested in this paper.
Wetland Suitability and Connectivity for Trans-Saharan Migratory Waterbirds
PLOS ONE, 2015
To complete their life cycle waterbirds rely on patchily distributed and often ephemeral wetlands along their migration route in a vast unsuitable matrix. However, further loss and degradation of remaining wetland habitats might lead to a configuration and size of stopovers that is no longer sufficient to ensure long-term survival of waterbird populations. By identifying optimal conservation targets to maintain overall habitat availability en route, we can accommodate an as yet absent functional connectivity component in larger management frameworks for migratory waterbirds, such as the Ramsar Convention and the EU Natura 2000 Network. Using a graph-based habitat availability metric (Equivalent Connected Area) we determine the functional connectivity of wetland networks for seven migratory waterbirds with divergent habitat requirements. Analyses are performed at two spatial extents both spanning the Mediterranean Sea and centered around Greece (Balkan-Cyrenaica and Greece-Cyrenaica). We create species-specific suitable habitat maps and account for human disturbance by species-specific disturbance buffers, based on expert estimates of Flight Initiation Distances. At both spatial extents we quantitatively determine the habitat networks' overall functional connectivity and identify wetland sites that are crucial for maintaining a well-connected network. We show that the wetland networks for both spatial extents are relatively well connected and identify several wetland sites in Greece and Libya as important for maintaining connectivity. The application of disturbance buffers results in wetland site-specific reduction of suitable habitat area (0.90-7.36%) and an overall decrease of the network's connectivity (0.65-6.82%). In addition, we show that the habitat networks of a limited set of species can be combined into a single network which accounts for their autoecological requirements. We conclude that targeted management in few but specific wetland complexes could benefit migratory waterbird populations. Deterioration of these vital wetland sites in Greece and Libya will have disproportionate consequences to the waterbird populations they support.
Biological Conservation, 2002
Morgan made detailed descriptions of 24 major Moroccan wetlands visited in 1978, with a total area of 4529 ha (Morgan, N.C., 1982a. An ecological survey of standing waters in North West Africa: III. Site descriptions for Morocco. Biological Conservation, 24,. We revisited these sites, and found that 25% of the wetland area had been destroyed by 1999. This loss was concentrated in wetland types of low salinity ( < 5 g/l NaCl), with a 98% loss of seasonal mesohaline sites, 41% loss of mountain lakes and 33% loss of seasonal Phragmites/Scirpus lacustris marshes. Surviving mountain lakes showed increased conductivities, suggesting reduced inflow. No loss of area of other wetland types was recorded, although degradation has occurred at all sites due to hydrological impacts, overgrazing or excessive reed-cutting, sedimentation, urban development, pollution, introduction of exotic fish and other causes. Similar threats face another 23 major Moroccan wetlands reviewed in this study. Of the 47 wetlands studied in total, only 10 have some kind of protection status. We assess the importance of these wetlands for waterbirds and aquatic submerged or floating plants. The number of plant species recorded is strongly correlated with the number of threatened waterbird species (but not the total number of waterbird species). Natural, freshwater wetlands most affected by wetland loss hold more species of aquatic plants and invertebrates, and are of great value for threatened waterbirds such as marbled teal (Marmaronetta angustrirostris), ferruginous duck (Aythya nyroca), ruddy shelduck (Tadorna ferruginea) and especially the crested coot (Fulica cristata). Most surviving natural, fresh wetlands are unprotected, and measures to conserve them are urgently required. Humanmade wetlands such as reservoirs have some value for threatened waterbirds (especially ruddy shelduck and marbled teal), but hold much lower densities of waterbirds than natural wetlands, and support fewer plant species. Thus, they do not compensate for the continuing loss of natural wetlands. #
The objective of the present work is to classify and select priority wetlands for the conservation of waterbirds in the international transboundary catchment area of the Mirim Lagoon (Brazil-Uruguay) and surrounding ecosystems. Layers were integrated within a GIS framework to select 97 priority areas that were classified in eight groups of importance for conservation of waterbirds. The following variables were considered: presence of waterbirds, type of productive activities with significant environmental impact, areas indicated as priority areas for conservation of biodiversity by the Brazilian government, wildlife areas in Uruguayan territory, areas indicated as "protected" in Uruguayan territory, connectivity based on the proximity between wetlands, wetland fragment shape, pollution load received by wetlands, and land use pressure in areas surrounding the wetlands. It was also possible to classify areas under higher vulnerability and to select priority areas under high threat and in need of actions to recover and restore sub-basins or areas surrounding the wetlands.
Building capacity in waterbird and wetland monitoring in eastern Africa
2007
The wetlands of eastern Africa support internationally important assemblages of plants and animals, and are a vital source of livelihood and water for many societies. The combined human population of Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Sudan, Tanzania and Uganda is estimated to be about 200 million. The region has an area of about 5.6 million km2 of which only 4.5% is open water/wetlands. Wetland conversion to agriculture often provides only short-term benefits and can pose long-term problems. The ever-increasing human population density coupled with the scarce water resources in Africa have put African governments under increasing pressure to allow further exploitation and drainage of wetlands. Lack of sufficient up-to-date information to guide policy and development programmes for the respective Africa governments is considered as one of the causes for the continued loss and degradation of wetlands. To fill this information gap, it was recognized that a standardiz...
Biological Conservation, 2017
The International Waterbird Census (IWC) is one of the most widespread biodiversity monitoring programs, assessing waterbird populations in the framework of several international agreements including the African-Eurasian migratory Waterbirds Agreement and the Ramsar Convention. In 2013, the IWC was coordinated for the first time across the whole of North Africa with the aim of developing recommendations for methodological improvements to current design in North Africa, as well as to update the conservation status of certain waterbird populations and wetlands of international importance. We show that coordinating the IWC across all five North African countries significantly improves knowledge of waterbird population sizes and distribution and confirmed that current North African Ramsar wetlands perform well in conserving waterbirds. Nevertheless, biodiversity conservation could potentially be further enhanced by designating additional Ramsar sites, which this study contributes to identifying. We show that reducing sampling effort by half over the entire region would have been sufficient to cover 100% of the species richness of wintering waterbirds recorded and N 98% of the total abundance. Finally, we show that larger wetlands are insufficiently sampled. These findings call for revised sampling design in a coordinated, region-wide framework. The maintenance, optimization and reinforcement of the IWC program over time on a regional scale, with the collected data made available in a shared database, seems essential in order to make appropriate conservation decisions for waterbirds and wetlands in the future. Adding a temporal dimension to these analyses will be critical to confirm the patterns observed in the 2013 census.
Supporting Materials The International Waterfowl (and Wetlands) Research Bureau
in 1993 3 Seconded by AWB for training and transfer of the Asian Waterbird Census from IWRB to AWB 4 Seconded by Tour du Valat/Luc Hoffmann 5 Seconded 1982-1984 from the provincial government of Schleswig-Holstein (Federal Republic of Germany), funded through the Deutscher Jagtschutz-Verband 6 Seconded by Dutch Ministry of Agriculture and Fisheries With apologies for any inadvertent omissions, the authors would welcome corrections and additions.