Fig.
5.(a) The shift of the population centroid in the suitable area and (b)
mean suitability change and the habitat change in different scenarios
Discussion
The effect of climate
change
The
result demonstrates that the habitat area of migratory birds will
significantly reduce in future, which mainly due to climate change (Gill
et al., 2019). Migratory species are more responsive to climate change,
as their migration process may be closely related to climate (Dunn et
al., 2009).
In summary, temperature plays a great role on the distribution of
migratory birds. Therefore, we investigated the importance of
environmental variables in 3 different climate zone (east part of south
temperate zone(STZ), middle subtropical zone(MSZ) and middle tropical
zone(MTZ)). Simultaneously, the environment variables differences in 6
basin (Haihe River Basin,
Yellow
River Basin, Huaihe River Basin, Yangtze River Basin, Southeast Basin
and Pearl River Basin) were also considered. We selected the most
important variables firstly and then calculated the percent contribution
of variables to figure out the constraint of migratory birds in
different regions.
4.1.1 How does climate influence the
basins?
The habitat area will decline most in the Yangtze River and Pearl River
basins of the southern and the area will increase most dramatically in
the Huaihe River basins (Fig.6).
The
area of habitat loss in the Yangtze River basin will reduce mostly 58880\(\text{km}^{2}\)in future.
The
Pearl
River basin and the Yellow River basin will decrease 34589\(\text{km}^{2}\) and 10287 \(\text{km}^{2}\) in future. Yangtze River
basin will loss 9.74% of the total habitat area in the basin. Pearl
River basin will loss 13.21% of the total habitat area in the basin.
And Yellow River basin will loss 9.83% of the total habitat area in the
basin.
The
habitat area of the Huaihe River basin will increase 13218\(\text{km}^{2}\), accounting for 8.16% of the total habitat area in
this basin. The decrement of habitat leads to the overlap of living
spaces between birds and humans (Flottum et al., 2016; Short et al.,
2011).