Prediction of the distribution of rare and endangered Dipterocarpaceae tree species in China and research on priority conservation areas

In order to simulate and predict the suitable habitat distribution of rare and endangered Dipterocarpaceae tree species in China, conduct conservation priority area and conservation GAP analysis, and to provide a basis for their protection and management.

Based on climate, terrain, soil, and human impact factors, MaxEnt model optimized was used with R language to simulate and predict the suitable habitats and changing trends of eight rare and endangered Dipterocarpaceae trees in China. The Marxan model was combined to identify priority areas for the protection of rare and endangered Dipterocarpaceae tree species and conducted a protection GAP analysis.

The results showed that: 1) The optimized MaxEnt model simulated the suitability zone of various tree species with high accuracy, with AUC values greater than 0.971; 2) Rare and endangered Dipterocarpaceae plants in China are mainly distributed in southern tropical regions such as Yunnan, Hainan, and Guangxi, with a relatively concentrated distribution range; 3) Annual mean temperature, isothermality, and human impact factors are the dominant factors affecting the distribution of the suitable habitat of Dipterocarpaceae tree species. Among these, annual mean temperature has the greatest impact on Dipterocarpaceae tree species, with an average contribution rate of 52.9%; 4) Under the SSPs126 and SSPs585 scenarios, the suitable areas for Dipterocarpus retusus, Hopea chinensis, Parashorea chinensis, Vatica mangachapoi decrease by 0.29% to 60.00%, and the center of gravity of the suitable areas shifts southwestward. Shorea assamica and Vatica guangxiensis expand by 8.60% to 52.22%, migrating northwest and northeast, respectively. The suitable areas for Hopea hainanensis and Hopea reticulata land decrease by 21.70% and 1.61%, respectively, under the SSPs126 scenario, and expand by 26.14% and 13.01%, respectively, under the SSPs585 scenario, with their centers of gravity shifting northeastward; 5) The priority areas for the protection of rare and endangered tree species of the Dipterocarpaceae family are mainly distributed in southern Yunnan Province and central Hainan Province. Currently, the protected area is only 0.515 6×10⁴ km².

The optimized MaxEnt model can effectively predict the suitable habitats of various tree species in the Dipterocarpaceae. The priority suitable habitats are not sufficiently protected, so efforts should be made to strengthen their protection and expand the distribution range of each tree species.