Patch Area and Soil Resource Availability Outweigh Heterogeneity in Shaping Karst Plant Diversity During Early...

Karst landscapes, vital to global terrestrial ecosystems, are characterized by fragmented soil patches with low resource availability and high resource heterogeneity. However, the relative roles of patch properties, soil resource availability, and heterogeneity in shaping plant species and phylogenetic diversity remain unclear. To address this, we conducted in situ observations across 27 10 m × 10 m plots in three karst abandoned farmlands to quantify the effects of patch properties, soil resource availability, and heterogeneity on plant species composition, species diversity, and phylogenetic diversity during early restoration. Patch area strongly influenced species richness (R), Shannon-Wiener index (H'), phylogenetic diversity (PD), and net relatedness index (NRI). Soil resource availability, notably soil depth and water content, consistently enhanced R, H', and PD. Conversely, soil resource heterogeneity had minimal impact on species diversity but significantly shaped NRI and nearest taxon index (NTI). Deterministic and stochastic processes jointly drove the community assembly of early herbaceous communities in karst abandoned farmland. These findings highlight that patch area and soil resource availability are primary drivers of plant diversity in karst restoration, offering a patch-scale framework to guide biodiversity conservation and vegetation recovery in degraded karst ecosystems.