THE STRUCTURE OF BREEDING BIRD COMMUNITIES IN THE SECONDARY FOREST AT CHANGBAI MOUNTAIN

This paper studied the structure of breeding bird communities in the secondary forest at Changbai Mountain.The results are as follows: 1.A total of 36 bird species were recorded in three sampling sites(Table 1).The numbers of species and pairs of breeding birds in each plot were:Ⅰ.23 species,40 5 pairs;Ⅱ.23 species,46 0 pairs;Ⅲ.27 species,73 5 pairs.Number of pairs generally increased with plot size. 2.The composition of breeding bird communities in the secondary forest showed a trend of increasing complexity with forest vegetation succession,from clear cutting slash to climax community. 3.There was a significant relationship between bird species diversity and vegetation stratum diversity, r=0 85,P0 05 (Table 3). 4.Species number coefficient of edge species generally incresed with the length of forest edge.The density of breeding bird within 50 m from forest edge was highest,being 45 paris/10 hm 2 in plot Ⅱ and 57 pairs/10 hm 2 in plot Ⅲ,respectively,and it decreased between 100 m and 150 m.At distances longer than 300 m from edge,the densities remained at a similar level(Fig.2). 5.The species number of the forest birds was 58% of total species in the secondary forest (20 years of age) plot.The density of cavity nesting and canopy nesting birds in the secondary forest plot was far lower than that in the primary broad leaved Korean pine forest plot.But the density of bush and ground nesting brids in bush and grass of the secondary forest plot was more than that in the primary forest plot.