Predicting the Potential Suitable Areas of Aythya baeri in the Yangtze River Basin under the Climate Change Scenario Based on Parameter Optimization MaxEnt Model

Researching the impact of climate change on endangered species is important for the long-term conservation and management of species. Taking Aythya baeri as the research object, the study adopted climate factor data, terrain data, and distribution data of Aythya baeri in the Yangtze River Basin from CMIP6 (coupled model intercomparison project phase 6), applied ENMeval data package in R language to optimize the RM (regularization multiplier) and FC (feature combination), and partitioned the data independently. The optimal MaxEnt model was used to predict the spatial distribution pattern and its centroid changes of potential suitability of Aythya baeri in the Yangtze River Basin in three periods (2041-2060, 2061-2070, 2081-2100) and four different climate scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) under contemporary climate conditions and future climate change. The results show that: (1) Based on the ranking of contribution rate and factor response curve of various historical periods, it is evident that dominant environmental factors affecting the suitable habitat of Aythya baeri in the Yangtze River Basin are altitude (ELE), annual average temperature (bio1) and coefficient of variation of precipitation (bio15). (2) Currently, the most suitable distribution area of Aythya baeri in the Yangtze River Basin is mainly concentrated in the middle and lower reaches of the Yangtze River and the northeastern part of the Sichuan Basin, with scattered populations found in some wetlands around lakes in Yunnan Province. (3) In the future, different climate scenarios will have diverse impacts on the potential distribution of Aythya baeri, with an increasing trend in the high-suitability areas compared to the present. Under the SSP3-7.0 climate scenario, the potential total suitable habitat area for Aythya baeri in the Yangtze River Basis tends to steadily increase with years. Under the SSP5-8.5 scenario, there appears to be a reversing trend in both the addition and loss of suitable habitats from 2081 to 2100. Compared to other climate scenarios, the total suitable habitat area under SSP2-4.5 tends to decrease gradually each year, with negative growth rates in both addition and loss rates. Meanwhile, the centroid shift results indicate that the distribution center of Aythya baeri is shifting westward. This study explored the predictive analysis method for the potential suitable habitats of Aythya baeri in a larger regional range under future climate scenarios, and revealed the impact of climate change on their suitable habitats. The results can provide a scientific reference for the protection of bird habitats in the Yangtze River Basin and the establishment of corresponding species conservation strategies.