Determinants of spatial patterns of plant diversity depend on the biogeographical affinities of the taxa − a case study in Northwest Yunnan, Southwest China

Abstract

The influence of the biogeographical affinities of taxa on the spatial determinants of plant diversity remains largely unknown. I explored the spatial patterns of tropical and temperate plant diversity in Northwest Yunnan and their primary determinants. Generalized linear models (GLMs) and variance partitioning were used to investigate the influences of predictors. Temperate genus diversity significantly increased with latitude, whereas tropical genus diversity did not show any obvious latitudinal trends. Proportions of tropical genera decreased with latitude, whereas those of temperate genera were on the contrary. Environment heterogeneity explained higher percentage of the spatial variation of temperate genus diversity than for that of tropical genus diversity. It may imply that the influence of environment heterogeneity on plant diversity may depend on the taxa's biogeographic affinities, which might modify the exploitation of environment heterogeneity, though the flora diversification induced by the uplifting of the Tibet Plateau may also play important roles. Climate predictors explained higher percentages of variation in the proportions of tropical genera than for the variations in tropical genus diversity. It may suggest that compared with the associations between genus diversity with tropical affinities and climatic conditions, the associations between the proportions of tropical plants and climatic conditions might more accurately reflect niche conservatism of tropical plants in the study area.