Prediction of Potential Habitats of <i>Zanthoxylum armatum</i> DC. and Their Changes under Climate Change

Climate change poses a severe threat to biodiversity. Greenhouse gas emissions have accelerated climate warming and significantly impacted species distribution and population dynamics. Zanthoxylum armatum DC. is an ecologically, medicinally, and economically important plant; it is cultivated as an economic crop at large scales in China, and is a valuable medicinal plant in India, Nepal, etc. A precise prediction of the potential distribution areas of Z. armatum will contribute to its protection and determination of its planting areas. In this paper, based on 433 distribution points and 19 climate factors, the MaxEnt model was used to analyze the spatial distribution pattern of Z. armatum between 1970 and 2000, predict its spatial distribution pattern in 2040–2060 (the 2050s) and 2081–2100 (the 2090s), and comprehensively assess the critical climate factors limiting its geographical distribution. The findings are as follows: (1) in the 1970–2000 scenario, the potential suitable distribution areas of Z. armatum include the subtropical monsoon climate regions of Japan, the Korean Peninsula, the south of the Qinling–Huaihe Line of China, and the regions along the southern foot of the Himalayas (India, Bhutan, Nepal, etc.), with an area of 330.54 × 104 km2; (2) the critical climate factors affecting the potential distribution of Z. armatum include temperature (mean diurnal temperature range, mean temperature of the coldest quarter, and temperature seasonality) and annual precipitation; (3) the distribution areas of Z. armatum will shift to higher latitudes and shrink under the three climate change scenarios in the 2050s and 2090s. In the 2090s–SSP585 scenario, the total area of suitable habitat will decrease most markedly, and the decrease rate of the highly suitable areas will reach up to 97.61%; only the region near Delong Town, Nanshan District, Chongqing City, will remain a highly suitable habitat, covering an area of merely 0.08 × 104 km2. These findings suggest that Z. armatum is susceptible to climate change. The border area between Guizhou Province and Chongqing City and the southwest district of Leshan City, Sichuan Province, will be a stable and moderately high potential suitable habitat for Z. armatum in the future. The above regions are recommended to be managed as key protected areas