关键词: 珙桐, 最大熵模型, 凉山山系, 人为干扰

Abstract: To furnish the theoretical foundation for conserving dove tree (Davidia involucrata), we examined the demographic number, age structure, and spatial distribution pattern of D. involucrata population in the Mabian Dafengding National Nature Reserve of Sichuan Province. Based on field survey data, the suitable habitat distribution and its influencing factors were simulated by MaxEnt model. The results showed that: (1) The reserve is rich in dove tree resources, with an estimated 11666.73 hm² of suitable habitat, constituting roughly one-third of the reserve’s total area and hosting about 27510 individuals. The population exhibited a marked scarcity of saplings and juvenile trees, presenting a typical inverted pyramid age structure that indicates a declining population. (2) Dove trees predominantly occupied areas along river valleys at altitudes ranging from 1000 to 2200 m, with the majority situated between 1200 and 2200 m. (3) The primary environmental variables affecting habitat suitability were the proximity to rivers, altitude, and the range of annual temperature, with optimal conditions being found within 0 to 250 m from rivers, at elevations of 1200 to 1900 m, and experiencing annual temperature fluctuations of 26.2 to 27.2 ℃. (4) Human activities such as bamboo harvesting and grazing severely threatened the habitats of dove trees, impeding seed germination and plant growth, and thereby adversely affecting population regeneration. We suggested initiating pilot conservation projects to strengthen the protection of dove tree germplasm resources in the Mabian Dafengding Reserve. Moreover, we should conduct experiments on dove tree breeding, population renewal, and innovative development and utilization. Artificial nurturing of saplings with problems in natural regeneration should be implemented to promote population sustainability. Planning bamboo shoot collection and livestock grazing areas, standardizing the bamboo shoot collection and grazing behaviors of local people around the reserve, and reducing human disturbances under the canopy were recommended. Upon meeting the necessary conditions, these measures can be expanded to the entire Liangshan Mountain range, which is crucial for the conservation of the dove trees.

Key words: Davidia involucrata, MaxEnt, Liangshan Mountains, human disturbance