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

Renzhong Wang,Linna Ma

doi:10.1038/srep27977

Abstract

There have been debates on the driving factors of C4 plant expansion, such as PCO2 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 C4 distribution and divergent patterns for different C4 taxa at continental scale in China. The results display that it is mean annual climate variables driving C4 distribution at present-day vegetation. Mean annual temperature is the critical restriction of total C4 plants and the precipitation gradients seem to have much less impact. Grass and sedge C4 plants are largely restricted to mean annual temperature and precipitation respectively, while Chenopod C4 plants are strongly restricted by aridity in China. Separate regression analysis can succeed to detect divergences of climate distribution patterns of C4 taxa at global scale.

Highlights

There have been debates on the driving factors of C4 plant expansion, such as PCO2 decline in the late Micocene and warmer climate and precipitation at large-scale modern ecosystems
The occurrence and distribution of C4 plants have been documented at different scales over the past couple of decades, there have been debates on C4 plant expansion at large-scale[1,16,17,18,19], for example, (i) what is the driving factor for C4 plant expansion, decrease in atmospheric CO2 concentration in the late Miocene or climate variability19−21? It had been hypothesized that PCO2 decline caused C4 plant expansion rapidly during the late Micocene (~8 to 4 Ma)[1,16,17], but some evidences suggested that C4 plant expansion was likely driven by addition factors, such as enhanced low-latitude aridity, seasonal precipitation[19] and fire[20] in the Miocene
Of the total vascular plants in China, 371 species are identified with C4 photosynthesis in 11 families (Table 1; Supplementary Table S1), but 90.83% C4 species occurring in Gramineae (53.64%), Cyperaceae

Summary

Introduction

There have been debates on the driving factors of C4 plant expansion, such as PCO2 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. Separate regression analysis can succeed to detect divergences of climate distribution patterns of C4 taxa at global scale Modern ecosystems, such as tropical savannas, temperate grasslands and semi-deserts, have a significant component of C4 plants[1]. There are few large data sets with which to examine occurrence and climate distribution pattern of different C4 taxa in modern vegetation at continental areas, resulting severely limits the accuracy understanding C4 plant expansion and the ecological implications Few found that the restriction of C4 grasses to warmer areas was due largely to their evolutionary history2. (ii) whether the different C4 taxa have similar climate distribution pattern in present-day at large-scale21,22? there are few large data sets with which to examine occurrence and climate distribution pattern of different C4 taxa in modern vegetation at continental areas, resulting severely limits the accuracy understanding C4 plant expansion and the ecological implications

Methods

Results

Conclusion