“Realistic strategies” and neutral processes drive the community
assembly based on leaf functional traits in a subtropical evergreen
broad-leaved forest
Abstract
We sought to assess effect of plant environmental adaptation strategies
and evolutionary history and quantify the contribution of ecological
processes to community assembly by measuring functional traits and
phylogenetic composition in local forest community. We selected 18
dominant tree species in a Lithocarpus glaber–Cyclobalanopsis glauca
evergreen broad-leaved forest and measured nine leaf functional traits
and phylogenetic data of each species. We analyzed the variation in
traits and trade-off relationships, tested phylogenetic effects on leaf
functional traits, explored the influence of phylogeny and environment
on leaf functional traits, and distinguished the relative effects of
spatial and environmental variables on functional traits and
phylogenetic compositions. The results showed the following: (i) Leaf
traits had moderate intraspecific variation, and significant
interspecific variation existed especially among life forms. (ii)
Significant phylogenetic signals were detected only in leaf thickness
and leaf area. The correlations among traits both supported “the leaf
economics spectrum” at the species and community levels, and the
relationships significantly increased or only a little change after
removing the influence of phylogeny, which showed a lack of consistency
between the leaf functional trait patterns and phylogenetic patterns. We
infer the coexistent species tended to adopt “realism” to adapt to
their habitats. (iii) Soil total potassium and phosphorus content,
altitude, aspect, and convexity were the most critical environmental
factors affecting functional traits and phylogenetic composition. Total
environmental and spatial variables explained 63.38% of the variation
in functional trait composition and 47.96% of the variation in
phylogenetic structures. Meanwhile, the contribution of pure spatial
factors was significantly higher than that of the pure environment.
Neutral- theory-based stochastic processes played dominant roles in
driving community functional trait assembly, but niche-theory-based
determinative processes such as environmental filtering had a stronger
effect on shaping community phylogenetic structure at a fine scale.