Variations in Leaf Functional Traits Across Ecological Scales in Riparian Plant Communities of the Lijiang River, Guilin, Southwest China

Abstract

Knowing plant functional trait variation is integral to understanding species coexistence and biodiversity maintenance. To explore how variations in a given trait vary across different spatiotemporal and ecological organizational scales, we performed a linear mixed model and varcomp function to partition the variance in four key functional traits (specific leaf area [SLA], leaf area [LA], leaf thickness [LTH], and leaf chlorophyll content [CHL]) from 5,418 individuals of 51 species across four nested ecological scales (plot, species, individual, and leaf) in riparian plant communities of the Lijiang River, Guilin, southwest China. We found that the relative contribution of all traits is similar: species (0.51–0.70) > individual (0.21–0.27) > leaf and error (0.09–0.20) > plot (0–0.07). For all traits, interspecific variability was higher than intraspecific variability and the plot level accounted for only a minute percentage of the total variance, despite relatively high species turnover between plots. These results suggest that the variation of leaf functional traits is dominated by interspecific variation, but data also showed a substantial amount of intraspecific trait variability. Thus, intraspecific variation of functional traits should be taken into account if assembly rules in plant communities are to be properly understood. The low, or even lack of, functional trait variance at plot level provides substantial support for the idea that trait-based habitat filtering could play a central role in plant community assembly.