ABSTRACT The mechanism of community assembly is a fundamental aspect of community ecology. In this study, the community assembly mechanism in karst areas was examined by investigating woody plants in 28 30 m × 30 m plots across seven distinct stages of succession in Maolan National Nature Reserve (Guizhou Province, southwestern China), a representative and well‐preserved subtropical karst forest system. The findings indicated that (1) Phylogenetic signals (Blomberg's K ) for most functional traits followed a unimodal pattern, being suppressed in early stages but peaking in Stage III ( K > 1) as Anacardiaceae ‐dominated communities transitioned toward Lauraceae ‐dominated stands. (2) The mean pairwise trait distance (traitMPD) and mean nearest trait distance (traitMNTD), along with the nearest taxon index (NTI), shifted from overdispersion (Stages I–III) to clustering (Stages IV–VII), reflecting that limiting similarity is eventually overridden by environmental filtering as lithological stress intensifies, while the net relatedness index (NRI) showed no significant variation. (3) Hierarchical partitioning confirmed that environmental distance (80.54%) exerted a much stronger influence than geographical distance (9.95%), collectively explaining 87.9% of community variation. We conclude that niche‐based processes remain the primary driver of karst forest succession. In early succession, where overdispersion indicates dominant competition, restoration should prioritize nitrogen‐fixing and deciduous pioneers to accelerate nutrient sequestration. Conversely, late‐stage clustering necessitates selecting phylogenetically distinct, stress‐tolerant clades to enhance drought insurance and navigate the intensified environmental filtering of maturing karst forests.
Hu et al. (Fri,) studied this question.