Suchergebnisse

Wetlands are key habitats connected physically and socially with processes occurring over a much wider territory. The biotic connection through dispersal mechanisms among wetlands is of primary importance to wetland management and policies. However, traditional wetland conservation approaches are based on the preservation of isolated sites considered to be of special importance (typically owing to their importance for concentrations of migratory waterbirds). Research linking local species richness and bird migration suggests that the effect of wetland loss on regional diversity might be much larger than what would be expected from direct habitat loss. Since the biotic connection among wetlands serviced by waterbirds appears to be more efficient within a limited range, the distribution of wetlands in space is a key aspect determining wetland connectedness even in the absence of direct hydrologic links. Protected areas should thus be defined with regard to waterfowl movements and waterbird migration as functional processes contributing to aquatic species migration and local species richness. This calls for a regional approach to wetland management within a continental context. This paper aims at defining an operational view of the dispersion function of wetlands and its implication for conservation policies. For this purpose, we examined the conservation policies of the Ramsar Convention (the international treaty that protects wetlands) and the European Union (as an example of relevant continental level policy-making) from the viewpoint of bird-mediated dispersal of aquatic organisms. We propose nine specific avenues for the inclusion of bird-mediated dispersal in the policy documents examined. Non-governmental organisations and other organisations working in waterbird conservation should also recognise the importance of their policies for aquatic biodiversity at broader levels and avoid compartmentalising their conservation activities. ; Peer reviewed

The White-headed Duck Oxyura leucocephala is listed as Endangered on the IUCN Red List of Threatened Animals. It is also listed on Annex I of the European Union Directive on the Conservation of Wild Birds (79/409/EEC) (Birds Directive), on Appendix II of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention), on Appendix I of the Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention), and Appendix II of the Convention on International Trade in Endangered Species (CITES Convention). The White-headed Duck is a highly aquatic diving duck of the stifftail tribe Oxyurini. Globally, there are four populations; two of which are declining, one stable and one increasing. The decreasing populations include the main Central Asian population of 5,000-10,000 birds and the Pakistan wintering population, which is on the verge of extinction. The resident North African population (400- 600 birds) is stable and the Spanish population (ca. 2,500 birds) increasing. The White-headed Duck occurs regularly in 26 countries, and in another 22 as a vagrant. Nine countries hold significant breeding numbers (Algeria, Islamic Republic of Iran, Kazakhstan, Mongolia, Russian Federation, Spain, Tunisia, Turkey, and Uzbekistan), but most are concentrated in Mongolia, Kazakhstan, Russian Federation, and Spain. Birds occur commonly on migration in 10 countries, and in winter (December to February) in 13. The most important wintering countries differ from year-to-year, presumably depending on weather conditions. In recent years, 10 countries have held over 1,000 birds (Azerbaijan, Bulgaria, Greece, Islamic Republic of Iran, Israel, Kazakhstan, Russian Federation, Spain, Turkey, and Uzbekistan – see Table 2). Seven countries hold significant numbers of birds throughout the year (Algeria, Islamic Republic of Iran, Russian Federation, Spain, Tunisia, Turkey, and Uzbekistan). ; Peer Reviewed