Predicting Climate Change-Induced Habitat Contraction of Disanthus cercidifolius subsp. longipes: A Warning Signal for Endemic Species Conservation

Global climate change is reshaping the distribution of suitable habitats for plant survival, with particularly severe implications for endangered plant species. Therefore, assessing the impact of climate on these species is essential for safeguarding their persistence in appropriate habitats. This study employed a Maximum Entropy model to systematically evaluate changes in the distribution of Disanthus cercidifolius subsp. longipes under current and future climate conditions. The key environmental factors determining the suitable habitats of D. cercidifolius subsp. longipes are soil water content, minimum temperature of the coldest month, and precipitation of the driest month. Currently, the optimal habitats are largely concentrated in southern China, including Hunan and Jiangxi Provinces. Compared with the current period, the suitable habitat area in most future periods contracts under all three climate scenarios, exceeding the present level only during 2021–2040 under SSP126 and 2061–2080 under the SSP585 scenario. The distribution centroid shifts northeastward under the SSP126, SSP245 and SSP585 scenarios. Niche overlap analysis further indicates that while substantial shifts in suitable habitat will occur, the overall migration range remains limited. These findings highlight that the distribution of D. cercidifolius subsp. longipes is jointly constrained by moisture availability and low-temperature tolerance, as represented by soil water content, precipitation of the driest month, and minimum temperature of the coldest month, as well as the complexity and potential risks in its response to future climate change. This study underscores the need for conservation strategies to address the dual constraints of water and temperature and to develop adaptive measures against potential future contractions in suitable habitat areas.