Climate-driven C4 plant distributions in China: divergence in C4 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

The worldwide leaf economics spectrum

Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate