Turnover on Chinese gradients

Tang, Z., Fang, J., Chi, X., Feng, J., Liu, Y., Shen, Z., Wang, X., Wang, Z., Wu, X., Zheng, C. & Gaston, K.J. 2012. Patterns of plant beta-diversity along elevational and latitudinal gradients in mountain forests of China. Ecography 35, 1083-1091.

Biodiversity patterns and their underlying mechanisms have long been focal topics of study for ecologists and biogeographers. However, compared with spatial variation in species richness (alpha- and gamma-diversity), beta-diversity, or the dissimilarity of species composition between two or more sites has until recently received limited attention. In this study, we explored the large-scale patterns of altitudinal turnover (beta-diversity) of plants in montane forests of China, based on systematic inventories of 1153 plots from 46 mountains distributed over ~30 degrees of latitude (21.9–51.7°N) and ~4100 m of altitude (160–4250 m). The beta-diversity of trees and shrubs declined significantly with increasing latitude. Along the altitudinal gradient, beta-diversity of both trees and shrubs showed non-significant trends in most mountains. Differences in climate explained ~30.0% of the variation in tree beta-diversity, with mean annual temperature being most important, and ~10.0% of that in shrub beta-diversity, with annual actual evapotranspiration and annual precipitation as the main predictors. However, climatic controls of beta-diversity varied dramatically in different biogeograpical regions. The beta-diversity of trees exhibited stronger, whereas that of shrubs showed weaker, climatic patterns in temperate and arid than subtropical regions. These results suggest that mechanisms causing patterns of beta-diversity may differ between latitudinal and altitudinal gradients, and among biogeographical regions; as a result, caution should be exercised in drawing close parallels between patterns and causes of beta-diversity along latitudinal and altitudinal gradients and among regions.