Waterbirds migration on the Azov-Black Sea coast of Ukraine and riskof west nile virus for humans

摘要

The biodiversity of Ukraine is characterized primarily by the influence of the East European Plain, which occupies 94% of the area of the country. The Danube River Basin, which runs along the Ukrainian-Romanian border before emptying into the Black Sea, has been recognized as a Global 2000 Ecoregion, based on selection criteria such as species richness, levels of endemism, taxonomic uniqueness, unusual evolutionary phenomena, and global rarity of major habitat types. In addition, Ukraine has 22 sites listed as wetlands of international importance under the RAMSAR Convention on Wetlands. There are more than 22,000 rivers in Ukraine with a total length of more than 170,000 km. Almost all (96%) of rivers in Ukraine are part of the greater Black-Azov Sea watershed; the remainder flows to the Baltic Sea. Many rivers provide spawning grounds for globally endangered fish. Dams and reservoirs have changed the water regime of many rivers. Most of the length of the Dnieper River within Ukraine, for example, is a cascade of six reservoirs, thus placing barriers to natural spawning routes, submerging a number of floodplains, destabilizing shores and slopes near the water line and destroying previously productive agricultural land.