Examination of Spatial Distribution Patterns and Density Dependence in Three Forest Communities on Mt. Huangshan

The spatial distribution pattern of species is one of the crucial methods to understanding population structure regulation and the maintenance of forest species diversity. Stabilizing mechanisms promote species coexistence within communities through intraspecific negative density or distance-dependent mortality. Despite numerous studies confirming an overall clustered distribution pattern in forest communities, our understanding of the spatial distribution patterns of different mycorrhizal and life history plant species, as well as their potential altitudinal gradient patterns, remains limited. This study was conducted in three forest dynamics plots established along the altitudinal gradient of Mt. Huangshan (evergreen broad-leaved forest, evergreen deciduous broad-leaved mixed forest, and coniferous and broad-leaved mixed forest). We used the bivariate pair-correlation function <i>g(r)</i> to assess the spatial distribution patterns of different mycorrhizal and life history plant species within the community. Additionally, we employed a random-labelling null model in a case-control design to explore the role of density dependence on dominant and occasional species at different life history stages. The results revealed that the distribution patterns of species in three different vegetation types were inconsistent and influenced by habitat heterogeneity. Dominant species typically experienced density dependence at short distances (less than 5m). As the spatial scale increased, the probability of density dependence decreased. Our findings lay the groundwork for further investigation into the mechanisms maintaining subtropical secondary forest communities.