Fig. 6.The change of habitat in different basins
The total migration direction of birds is different from that in different regions. The shifts of population centroid in different regions of habitat are shown in the Fig.7a. The movements of these regions showed that the tendency of the distribution is moving towards the mainstream, which also revealed that the distribution of migratory birds in future scenario will be compressed. The population centroid in Yangtze River basin will move far 44.94 km towards southeast. The population centroids in Haihe River Basin, Pearl River Basin, Yellow River Basin, Southeast Basin and Huaihe River Basin will move 34.26 km, 31.03 km, 25.33 km, 23.48 km and 16.68 km.