Intermediate Anthropogenic Disturbances Boost Taxonomic and Phylogenetic Diversities but Reduce Functional Diversity in Subtropical Forests of Eastern China

Anthropogenic disturbances significantly impact plant biodiversity in subtropical forests. While prior research has primarily concentrated on taxonomic diversity, other dimensions of biodiversity, such as phylogenetic and functional diversities, remain insufficiently explored. This study simultaneously investigated these three facets of plant diversity in subtropical forests with two distinct disturbance histories in eastern China, aiming to elucidate the effects of intermediate anthropogenic disturbances on biodiversity. Disturbed deciduous broadleaf forests exhibited markedly lower Pielou evenness index values compared to their conserved counterparts (<i>p</i> < 0.05). Disturbed evergreen broadleaf forests demonstrated significantly higher species richness, Shannon-Wiener index scores, and phylogenetic diversity relative to those found in conserved forests (<i>p</i> < 0.05). Furthermore, both disturbed deciduous broadleaf and mixed evergreen-deciduous broadleaf forests displayed significantly reduced functional richness and quadratic entropy coefficient values when compared with their conserved equivalents (<i>p</i> < 0.05). Forest type exerted a significant influence on all three dimensions of biodiversity (<i>p</i> < 0.05). In conclusion, intermediate anthropogenic disturbances have the potential to enhance both plant taxonomic and phylogenetic diversities while concurrently diminishing functional diversity within the subtropical forests of eastern China. The mechanisms driving responses in plant diversity to intermediate anthropogenic disturbances vary according to forest types.