毛红椿(Toona ciliata var. pubescens)为楝科香椿属落叶乔木，被列为国家二级保护濒危物种。了解未来气候变化对中国毛红椿潜在适生区分布格局的影响，加强栖息地与环境因素间影响、适宜度等的评估，为其物种保护与生态恢复提供依据。

基于来自中国江西、云南、安徽、浙江、湖南、广西、贵州、四川8 个省(区)的53个地理分布点， 运用 MaxEnt 生态位模型， 选取当前、未来 2040 s 和 2060 s 时段，于 RCP 2.6、RCP 4.5、RCP 8.5的3种温室气体排放情景下进行模拟预测，然后将分布模拟图经MapGIS 10.0识别、几何精校正与矢量化处理，进一步比较分析毛红椿未来分布格局的气候响应。

本生态位模型的模拟效果理想，当前适生分布因东西向低纬度分布特征显著而呈形似狭长岛屿状分布，位于中国东部季风区，以雨热同期的亚热带季风气候为主，最热季平均降水量和气温决定毛红椿的适生分布区域，最冷月最低气温可能是其分布的主要限制气候因子。 未来气候变化下，受未来分布区的降水量降低、冬季低温升高的气候变化影响，当前适生区可能发生华中分布区域以东的规模性消退，削减至当前规模的 31.90% ~63. 73% ；未来适生分布将随气候变化情景梯度向西迁移，其地理中心将移至云南省林区；较适生以上分布区域的分布格局波动将趋于集中，并将迁移至中国高海拔分布区的云南、四川、贵州等省境区域。

总体上，未来气候可能对毛红椿的适宜程度、分布范围、分布规模与斑块状连续分布格局等产生负面影响，并形成较适生及以上区域的独岛状分布，进一步加剧毛红椿的濒危风险。 建议加强对当前保护区内毛红椿不同地理居群的保护，将云南、四川、贵州等省列入未来气候变化监测的核心区域，分析毛红椿居群与气候环境波动，以及与地形小生境适应、变化的规律。

Toona ciliata var. pubescens, a deciduous broad-leaved plant, is a secondary endangered species under state protection in China. Understanding the impact of future climate change on the potential distribution patterns of T. ciliata var. pubescens in China and assessing the interaction between its habitat and environmental factors would contribute to its conservation and ecological restoration.

The MaxEnt model was applied to the distribution data obtained from 53 locations spread across the Jiangxi, Yunnan, Anhui, Zhejiang, Hunan, Guangxi, Guizhou and Sichuan Provinces to estimate habitat suitability at present and in the future (by 2040s and 2060s) under three greenhouse gas emission scenarios of RCP 2.6, RCP 4.5 and RCP 8.5. The output data were processed using MapGIS 10.0 software, including identification, geometric correction and vectorization processing, and then used to analyze the response of T. ciliata var. pubescens to future climate change.

The simulation results of the MaxEnt model were verified to be ideal. The current distribution pattern of T. ciliata var. pubescens was similar to a narrow island with its distinctive east-west features. This pattern was determined by the mean precipitation in the hottest quarter and temperature in a given year; the minimum air temperature of the coldest month may be the main limiting climatic factor for its distribution. The results illustrated that the suitable T. ciliata var. pubescens habitats will make a large-scale recession toward the east of central China under future climate change, mainly due to a decrease in rainfall and an increase in the minimum air temperature in winter. Under different greenhouse gas emission scenarios, the reduction rates in its habitable areas would vary from 31.90% to 63.73 %, and its geographic center would probably migrate into Yunnan Province. The distribution patterns in more suitable areas will become more concentrated and might migrate to the high-altitude areas of the Yunnan, Sichuan and Guizhou Provinces.

In brief, future climate change is likely to have negative effects on the suitability, distribution range, distribution scale, and patchy continuous distribution pattern of T. ciliata var. pubescens, and its distribution to higher suitability areas might be more concentrated. These combined effects will increase the degree of its future endangerment. We recommend strengthening the protection measures for T. ciliata var. pubescens not only in the currently protected areas but also in the sensitive areas of climate change, such as Yunnan, Sichuan, Guizhou and other Provinces. Further research should be focused on the relationship between the population fluctuation of T. ciliata var. pubescens and climate change as well as its adaptation to a particular ecological niche.