Functional diversity and spatial variation of shrubs in Rhododendron latoucheae communities distributed along an altitude gradient in Mt. Jinggang, Jiangxi, China

Researching on the spatial variation of community functional diversity along altitudinal gradients can increase our understanding of the relationship between functional diversity and ecosystem function and their maintenance mechanisms. This research investigated the community composition and structure of shrubs in Rhododendron latoucheae communities distributed along an altitudinal gradient in Jinggang Mountain, Jiangxi province to uncover the characteristics of species diversity, functional diversity and environmental factors, and the relationships between them. The results showed that: 1) The species diversity and functional diversity of shrub species in the community changed in different patterns along the altitudinal gradient. The species diversity indices(richness index, Shannon-Wiener index, Pielou index, and Simpson index) decreased with increasing altitude, meanwhile the functional diversity indices displayed a complex pattern. The functional volume(FRic), functional evenness(FEve) and functional dispersion(FDis) significantly decreased, but the functional divergence(FDiv) and quadratic entropy(Rao) increased with increasing altitude; 2) There was a complicated correlation between species diversity and functional diversity of communities. FRic and FEve were positively correlated with the richness index; Simpson dominance showed significant linear correlations with Rao, FDis and FDiv; 3) Environmental factors such as slope position, soil nitrogen and phosphorus content of the community had important influences on the functional diversity of shrubs. The relationships between species diversity and functional diversity of shrubs in R. latoucheae communities and their response to environmental changes determine the community ecosystem function.