Abstract: Biodiversity assessment has long been the central to ecology, biogeography, and conservation biology. The lack of baseline biodiversity information constrains refined and quantitative assessments of biodiversity at regional scales. We conducted a comprehensive survey of the Cangshan Mountain region between 2022 and 2024, with biodiversity and spatial data collected across the entire region using the “Cloud-based Scientific Survey” platform. An assessment framework based on ten indicators was developed, including ecosystem diversity, vegetation index, species richness, kernel density, nationally protected species richness, endemism, threat status, and degree of alien invasion. Employing an integrated assessment method, regional biodiversity was quantitatively evaluated based on equal-area grid cells (2 km×2 km). The current status, spatial patterns, and environmental drivers of biodiversity were evaluated, with analysis including a conservation gap assessment. Results showed that overall biodiversity indices were high (BI: 0.08-0.82), with a pattern of higher in the northern, central-southern, and central-western mid-high altitude zones and lower in the eastern and western low-altitude zones. High-value sites were primarily located in mid-altitude (2400-3300 m) forested regions, whereas low-value sites were concentrated in zones with intensive human disturbance (e.g., construction and agriculture) at lower elevations on the eastern and western sides of the region. The GAM model analysis showed that annual average precipitation, elevation, and the shortest distance to the residential area were the key factors influencing biodiversity. Mean annual precipitation showed a significant linear positive effect (P<0.001). Altitude exhibited a significant single peak effect that increased first and then decreased (P<0.001). The shortest distance to the residential area showed a significant non-linear effect (P=0.02). They collectively explained 48.8% of the variation in biodiversity. Further analysis indicated that the Cangshan Protected Area’s boundaries largely ensure effective coverage of regional biodiversity, though its internal functional zoning requires further optimization. Overall, this study offers a decision-making basis for the conservation and management of the Cangshan Protected Area.

Key words: Cangshan Mountain, biodiversity, spatial pattern, nature reserve