关键词: 黄心梓木, MaxEnt模型, 气候变化, 地理分布预测, 主导环境因子, 迁移路线, 保护措施

Abstract:

Objective: This study intends to predict the suitable habitat of Huangxin under different environmental scenarios in current and future periods based on the MaxEnt model. The aim is to explore the distribution of Huangxin, provide a scientific basis for the protection and sustainable use of Huangxin and also serves as a reference for the prediction and protection of potential suitable habitats for endangered plants. Method: This study, based on the MaxEnt model and incorporating environmental variable data from the present and future periods (2030s, 2050s, 2070s) , simulated and predicted the potential geographic distribution of Huangxin under different climate scenarios. Through a comprehensive analysis of the environmental factors limiting its spread, we have formulated targeted conservation measures. Result: 1) The area under the curve (AUC) values of all groups in the MaxEnt model were higher than 0.9, indicating high accurate model predictions. 2) Huangxin has a narrow potential suitable area in China, with a total current suitable area of 50 416 km². The high suitable area is only 2 309 km², located in parts of southern and southwestern Guizhou Province. The medium suitable area (14 288 km²) is distributed around the high suitable area. The low suitable area, amounting to 33 819 km², is distributed in central Guizhou Province, Guangxi Zhuang Autonomous Region, Yunnan Province and Sichuan Province. Under future climate conditions, the potential suitable area for Huangxin shows a trend of first expanding and then contracting over the three periods. Among them, the total suitable area could reach its maximum (70 313 km²) in the 2030s under the high forcing (SSP5-8.5) scenario, with an increase of 39% compared to the current total suitable area. 3) The precipitation of the driest month (bio14), altitude (bio20), isothermality (bio3), and annual precipitation (bio12) are the dominant environmental factors limiting the distribution of Huangxin. 4) Under future climate scenarios, the potential suitable area for Huangxin shows a trend of first expanding and then contracting, with a migration direction first northward and then southeastward. 5) Based on the current situation of Huangxin, we propose relevant conservation measures: delineating protected areas in situ within the high suitable range; conducting relevant breeding experiments in potential suitable areas such as western Hubei Province and northeastern Chongqing Municipality to expand its planting area; and establishing a germplasm resource bank. Conclusion: The suitable habitat for Huangxin is relatively narrow, with the medium to high suitable areas predominantly concentrated in southwestern Guizhou Province. Low suitable areas may also be distributed in parts of Guangxi Zhuang Autonomous Region, Yunnan Province, Sichuan Province, Chongqing Municipality, and Hubei Province besides Guizhou Province. The current suitable area for Huangxin has not reached saturation, and it is projected to reach its maximum area in the 2030s. Under future climate scenarios, the area of potential suitable habitats is expected to first expand and then contract. Given the current status of Huangxin, it is recommended to carry out human-assisted measures such as habitat restoration and rapid promotion of population recovery.

Key words: Huangxin (Catalpa), MaxEnt model, climate change, geographic distribution prediction, dominant environmental factors, migration route, conservation measures