Leaf stoichiometry is synergistically-driven by climate, site, soil characteristics and phylogeny in karst areas, Southwest China

Leaf stoichiometry and its biogeography play vital roles in nutrient cycling of plant communities. To understand the potential drivers of leaf stoichiometry in karst ecosystems, we measured leaf morphological traits (dry mass content (DM), specific leaf area (SLA)), and biochemical traits (C, N, P, K and Ca stoichiometry) of 53 species of different functional groups, as well as soil properties, across seven karst sites in Southwest China, and explored the relationships between these leaf traits and environmental factors. The results showed that: (1) in karst areas of Southwest China, there were higher leaf C and Ca concentrations as well as higher N/P and K/P ratios compared to other ecosystems, plants were more limited by P rather than by N; (2) mean annual temperature positively influenced leaf N, P, and Ca, while mean annual precipitation exerted more influence on leaf K; (3) a strong phylogeny signal was detected in leaf N ( p < 0.05), and significant influence of species composition on the variance of leaf N, K, and Ca was observed ( p < 0.05); (4) the influence of soil properties on leaf P and Ca, and the influence of leaf features (SLA and DM) on leaf K were also observed based on a variance partitioning analysis. Abiotic factors such as soil, site, and climate were more important than biotic factors (leaf features and phylogeny) in determining leaf N, P, and Ca. In general, the driving factors exhibited a synergistic effect on leaf stoichiometry across different sites, offering a key mechanism that needs to be integrated into the modeling of biogeochemical nutrients cycling in karst ecosystems.