西安建筑科技大学：《水资源利用与保护》参考资料_Water resources in the world_Watersheds of the World - Tropical Deforestation

Watersheds of the World- Tropical Deforestation Average Rate of Deforestation p Projection: Robinson Citation: Revenga, C.S. Murray, I Abramovitz, and A Hammond, 1998 eEarthTrends 2002 Work

Watersheds of the World - Tropical Deforestation Map Projection: Robinson Citation: Revenga, C., S. Murray, J. Abramovitz, and A. Hammond, 1998. Watersheds of the World: Ecolo © EarthTrends 2002 World Resources Institute. All rights reserved. Fair use is permitted on a limited scale and for educational purposes

Pd ation rate by subbasin in the tropics for the period 1980 ough 1990. presented are not annual rates, but mean percent loss of forest for the period 1980-1990. between 15 and 30 percent for the period 1980-1990 Souree unpublished data from FAo(1980 and 1990) eEarthTrends 2002 Work

Analytical Overview: Source: Watershed specific deforestation data were only available for 62 basins in the tropical forest areas. Deforestation rate is based on the United Nations Food and Agriculture Organization (FAO) data on forest area for the years 1980 and 1990. Deforestation rate was calculated for each district as forest area lost divided by forest area in 1980. The values were then converted to a grid and the mean was calculated for each basin. Data presented are not annual rates, but mean percent loss of forest for the period 1980-1990. Revenga, C., S. Murray, J. Abramovitz, and A. Hammond, 1998. Watersheds of the World: Ecological Value and Vulnerability. Washington, DC: World Resources Institute, based on unpublished data from FAO (1980 and 1990). Description: This map shows the deforestation rate by subbasin in the tropics for the period 1980 though 1990. The conversion of forestland to other land uses in a watershed is an indicator of watershed vulnerability. Of the 62 basins analyzed, 14 lost more than 10 percent of their forest cover between 1980 and 1990. Almost all these basins, except for Lake Tanganyika, are found in Central and South America and in mainland Southeast Asia. Minor basins in the Amazon and Paraná in South America, and the Indus, Mekong, Irriwady, and Chao Phrya basins in Asia have the highest average deforestation rate, between 15 and 30 percent for the period 1980 - 1990. © EarthTrends 2002 World Resources Institute. All rights reserved. Fair use is permitted on a limited scale and for educational purposes