Fig. 4. Habitat of the species groups identified by MaxEnt. Each panel depicts the habitat of each bird group based on the different scenarios.
The distributions of most endangered species have changed by comparing the distributions of present and future climate scenarios. The distributions of 9 species are shown a distinct reduction in distribution and 8 species will maintain their current habitat area. The habitats of CR_3, CR_1, VU_3 and EN_4 decease 56001\(\text{km}^{2}\), 26652\(\text{km}^{2}\), 44464 \(\text{km}^{2}\) and 56608 \(\text{km}^{2}\). The species that maintain the existing habitat area mainly include EN_3, CR_2 and EN_1.Specifically, the habitats of several species will expand under the influence of climate change in future. All the expand species are mainly distributed in Shangdong and Hebei province of the middle-eastern China, consistent with total distribution (Northrup et al., 2019; Shen et al., 2015).
Not only the distributions have changed greatly, but also the population centroids shift a lot(Fig.5a, the abbreviation of species in shown at Table.S4).The estimation of birds’ population migration direction on a large scale is not effective for small areas. The population centroid of migratory birds, shifting in small scale areas, are easily influenced by the local topography, and could not match with the total shift of birds in country scale. The migration direction of each species is different and the offset distance is different.
Species distribution will change obviously in future by detecting from the population centroid. The population centroids of most species migrate long distances from the current centroids. In particular, some population centroids of critically endangered species have experienced a huge offset in future. Especially CR_3 will move 292.88 km to southeast with the mean suitability decreasing 2.67%, which may exacerbate the survival crisis. The endangered species will also change greatly in future as EN_2 moving 197.36 km to southwest and EN_5 moving 174.16 km to northwest. The most distributions of vulnerable species will move long distances from the current and easily get adverse effects from climate change. In future, VU_8 will move 327.74 km towards southwest with mean suitability decreasing 30.56% and VU_7 will move 419 km to southeast with mean suitability decreasing 10.82%. In general, species distribution at high latitudes may move southward in future with the decline in mean suitability. Species distribution at middle latitudes may move eastward. The movement of species means that their habitats are compressed and the living risk rise.