STUDY ON THE BIRD COMMUNITY STRUCTURE IN THE FOREST-STEPPE TRANSITION ZONE

The bird community structure was studied in forest-steppe transition zone of Saihanba area between 1993 and 1998. 103 bird species were found, the composition of the bird community was very complex. Values of similarity coefficient of bird communities in four habitat stairs were low. The community structure varied with harizontal habitat stairs. The forest is the main habitat of the birds. The density of birds within 50 m from forest edge to forest inside and 30 m from forest to steppe were the highest. The community structure varied with the vertical spatial levels of forest vegetation, the species diversity and even distribution varied in vertical space. Six vertical perching and foraging guilds were distinguished by using cluster analysis and principal components analysis. These guilds shared the perching space and the food by their perching and foraging behavior pattern, the birds of guide inside could coexist by more detailed ecological partition and niche orvelap.