Climate-driven C(4) plant distributions in China: divergence in C(4) taxa

There have been debates on the driving factors of C(4) plant expansion, such as PCO(2) decline in the late Micocene and warmer climate and precipitation at large-scale modern ecosystems. These disputes are mainly due to the lack of direct evidence and extensive data analysis. Here we use mass flora data to explore the driving factors of C(4) distribution and divergent patterns for different C(4) taxa at continental scale in China. The results display that it is mean annual climate variables driving C(4) distribution at present-day vegetation. Mean annual temperature is the critical restriction of total C(4) plants and the precipitation gradients seem to have much less impact. Grass and sedge C(4) plants are largely restricted to mean annual temperature and precipitation respectively, while Chenopod C(4) plants are strongly restricted by aridity in China. Separate regression analysis can succeed to detect divergences of climate distribution patterns of C(4) taxa at global scale.