关键词: 南岭山地, 亚热带森林, 常绿阔叶林, 群落结构, 物种多样性

Abstract

Aims: The Nanling Mountains serve as a key ecological corridor and transition zone between the mid- and south-subtropical regions of China. Both the tropical and temperate floras converge in this region, and therefore it is the northern or southern distributional boundaries for many plant species. 

Methods: Based on 16 1-ha forest dynamics monitoring plots across the Guangdong Nanling National Nature Reserve, encompassing all major vegetation types throughout the region, we analyzed the species composition, floristic characteristics, size distribution, and spatial distribution of woody plants with ≥ 1 cm DBH (diameter at breast height). 

Results: A total of 75,141 individual trees and shrubs (100,923 stems, including branches) were recorded across the 16 plots, representing 582 species, 220 genera, and 78 families. Among these, 137 tropical genera (398 species; 62% of total genera, 68% of total species), 80 temperate genera (174 species; 36% of total genera, 30% of total species), and 3 cosmopolitan genera (10 species) were identified. The plot with the highest species richness contained 229 species, whereas the least diverse plot contained only 87 species. Dominant species in the tree layer varied among plots, effectively reflecting the primary forest types in the Nanling Mountains. Overall, all the plots exhibited stable inverse J-shaped size distributions for all the individuals together, but the dominant species in each plot and the same species among the plots varied considerably in size distribution. The results of species-area curves revealed substantial differences in species accumulation rates and saturation thresholds among the 16 plots. On average, sampling a 400 m² plot captured only 30% of the total species richness, whereas 90% species coverage was achieved at a plot size of 6,600 m². Spatial distribution patterns varied significantly across vegetation types and diameter classes. Dominant species exhibited distinct habitat preferences, and the same species (e.g., Schima superba and Pinus massoniana) displayed divergent spatial patterns across plots. 

Conclusion: This study reveals substantial variation in plant species composition, community structure, and species’ spatial distributions among distinct vegetation types in the Nanling Mountains. These findings provide a foundation for long-term biodiversity monitoring in subtropical montane forests and support the development of the national park system.

Key words: Nanling Mountains, subtropical forest, evergreen broad-leaved forest, community structure, species diversity