Altitudinal patterns of plant species richness in the Honghe region of China

Understanding the key mechanisms shaping the altitudinal patterns of biodiversity is critically important in ecology and biogeography. in this study,we examined the patterns of species richness of different plant groups characterized by different life forms and range sizes along the altitudinal gradient in the honghe region of china,one of the global hotspots of biodiversity. the relative contributions of area,the mid-domain effect (mde) and temperature in shaping these patterns were evaluated. our results revealed that the altitudinal patterns of species richness of seed plants,trees,shrubs,herbaceous plants,narrow-range plants (range ≤ 600 m) and broad-range plants (range > 600 m) all exhibited bell-shaped distributions. the analyses showed that area accounted for the largest percentage of the variation in species richness for all plant groups,followed by mean annual temperature,which served as the measure of available ambient energy in our analyses. although mde determined the smallest percentage of the variation,it still explained ≥ 67.3% of the species richness for all plant groups except fornarrow-range plant species. the results of the variation partitioning analyses suggested that the majority of the variance in species richness was explained by the collinearity amongarea,mde,and temperature. moreover,different plant groups demonstrated different relationship sensitivities with the explanatory variables,which reflected the different physiological requirements of woody and herbaceous plants,and greater influence of geometric constraint on the placement of larger range sizes. © 2017,pakistan botanical society. all rights reserved.