关键词: 黑鹳, 适生区, 气候变化, 最大熵模型

Abstract: Black Stork (Ciconia nigra) is a firstclass national protected animal in China with endangered populations. We used the data of 100 distribution points of C. nigra and 14 environmental variables, including climatic, vegetation, topographic, hydrologic, and human disturbances, to assess the potentially suitable distribution areas of C. nigra in Beijing and to explore the impact of climate change on its suitable habitat. The maximum entropy model (MaxEnt) was then applied to simulate the potentially suitable distribution of C. nigra in Beijing under current and three future climate scenarios. The contribution rates of environmental variables to the species distribution model were analyzed to evaluate the key factors influencing potentially suitable distribution. We further analyzed the changes of potentially suitable distribution areas and patterns. The results showed that: (1) The key environmental variables influencing potentially suitable distribution of C. nigra were land cover types (24.0%), distance to rivers (18.8%), elevation (18.3%), distance to roads (9.1%), annual precipitation (5.6%), and precipitation in the driest month (5.4%). (2) Currently, the potentially suitable distributions of C. nigra in Beijing were mainly concentrated along river basins and surrounding areas, including the Juma River in Fangshan, Yongding River in Mentougou, Guanting Reservoir in Yanqing, and Miyun Reservoir. The total suitable areas were estimated at 2168.89 km², accounting for 13.2% of Beijing’s total area, with highly suitable areas of 58.36 km² (2.7%), moderately suitable areas of 415.87 km² (19.2%), and lowly suitable areas of 1694.66 km² (78.1%). (3) The potentially suitable distribution area of C. nigra showed an overall increasing trend under SSP1-2.6 (Low-emission Economic Pathway) and SSP2-4.5 (Mid-emission Economic Pathway) scenarios, while it exhibited an initial increase followed by a sharp decrease under SSP5-8.5 (High-emission Economic Pathway) scenario. The contraction areas predominantly occurred in southwestern and central regions of Beijing such as Fangshan, Mentougou, and Changping. Conversely, the expansion areas were mainly distributed in northern regions of Beijing like Yanqing, Huairou, and Miyun. Under different climate scenarios, the centroid of C. nigra’s potentially suitable distribution shifted towards the northeastern and higher altitude regions. Our results provide scientific basis for the conservation of C. nigra resources and for formulating effective strategies to cope with climate change.

Key words: Ciconia nigra, suitable habitat, climate change, MaxEnt