Effects of Ecological Factors on the Spatial Distribution of Food Plants in Hainan Gibbon (Nomascus hainanus) Habitat: Conservation and Habitat Restoration Insights

Food resources are crucial for conserving endangered species. Quantifying the distribution of food plants and their driving factors in Hainan gibbon habitats helps to understand food supply characteristics and guide targeted habitat restoration. This study was based on a survey of 122 grid plots (20 × 20 m), categorized as food plants by size (large: diameter at breast height [DBH] ≥ 15 cm; small: 1 cm ≤ DBH < 15 cm) and seasonality (dry season and preferred food plants). The results showed: 1) Significant differences in the ecological factors between high-altitude and low-altitude habitats ( t  = − 9.04–11.03, P  < 0.05). 2) Significantly higher species richness ( t  = 2.08–5.02, P  < 0.05) in high-altitude habitats than low-altitude ones, with a long dry season, and preferred food plants were more abundant in the A and C family groups. 3) Key factors affecting the spatial distribution of food plants included elevation, the soil carbon-to-nitrogen ratio, average temperature, and annual precipitation, with effects varying by food plant type and elevation. These findings indicate that successional low-altitude secondary forests are potential habitats for Hainan gibbons (e.g., family group E) but require further restoration for population growth and spatial expansion. In contrast, high-altitude areas remain ideal. This research underscores the importance of tailored restoration strategies for different food plant groups. Practices, such as thinning, are recommended to enhance food plant diversity and ensure a stable food supply. Future research should focus on human disturbances and plant interactions to fully understand the food plant distribution patterns.