Changes in Bird Resource at An''xi Extra-arid Desert National Nature Reserve
安西极旱荒漠国家级自然保护区鸟类资源的消长变化

The An'xi Extra-arid Desert National Nature Reserve,situated in the west of the Hexi Corridor in Gansu Province,is a nature reserve for desert eco-system.Bird species and their abundances in the reserve were surveyed during 1988-1989.In order to gain an understanding of the changes of bird resource at the reserve since 1988,line-transect method was used to investi-gate bird species,amount and environmental condition during 2002-2004.A total of 103 species of birds were recorded in the reserve during this period.In comparison with the record of 1988-1989,31 were new(among which three species were new records for Gansu Province),but 36 disappeared.The state protected birds in China decreased from 18 species in 1988-1989 to 16 species in 2002-2004.Six additional protected species of birds were recorded,but eight species were not re-counted in the second survey.Fifteen birds listed in Convention on International Trade in Endangered Species of Wild Flora and Fauna(CITES)were recorded during 1988-1989 and 2002-2004,but the species changed.There were eight species that were listed in China Red Data Book of Endangered Animals:Aves in 1988-1989,however,six were in 2002-2004.Aegypius monachus and Phoenicurus alaschanicus were listed in Threatened Birds of Asia in 1988-1989,and Otis tetrax and Falco naumanni in 2002-2004.Comparing bird abundance between 2002-2004 and 1988-1989,the amount of birds in spring and summer decreased,but those in autumn increased.Specially,species and amount of dominant species significantly changed in each season between 1988-1989 and 2002-2004.The main factors that led to the change of bird resources in An'xi Extra-arid Desert National Nature Reserve were bird migration and human activities.