Emigration and Mortality of Black-necked Swans (Cygnus melancoryphus) and Disappearance of the Macrophyte Egeria densa in a Ramsar Wetland Site of

摘要

Ecosystem services and the function of wetlands are increasingly altered .by human actions around the world. Wetland ecosystems are scientifically and socially important because they represent high-biodiversity areas and water reservoirs. In southern Chile (ca. 39-41 deg S), there are several coastal and inland wetlands larger than 500 ha that are currently threatened by adjacent urban locations due to the discharges of industrial wastes, conversion of soil to agriculture, and water extraction. These Chilean wetlands are mostly located on the coastal range of the Valdivian Rainy forest, which is biologically unique due to its high plant diversity and is also being affected by fragmentation resulting from extensive land use changes. These characteristics of the wetland and Valdivian forest have been the promoters of national and international efforts that highlight the need for conservation of these ecosystems (1).