环境地球化学国家重点实验室知识库

The leaf carbon isotope ratio (δ¹³C) is a useful parameter for predicting a plant's water use efficiency, as an indicator for plant classification, and even in the reconstruction of paleoclimatic environments. In this study, we investigated the spatial pattern of leaf δ¹³C values and its relationship with plant functional groups and environmental factors throughout China. The high leaf δ¹³C in the database appeared in central and western China, and the averaged leaf δ¹³C was -27.15‰, with a range from -21.05‰ to -31.5‰. The order of the averaged δ¹³C for plant life forms from most positive to most negative was subshrubs > herbs = shrubs > trees > subtrees. Leaf δ¹³C is also influenced by some environmental factors, such as mean annual precipitation, relative humidity, mean annual temperature, solar hours, and altitude, although the overall influences are still relatively weak, in particular the influence of MAT and altitude. And we further found that plant functional types are dominant factors that regulate the magnitude of leaf δ¹³C for an individual site, whereas environmental conditions are key to understanding spatial patterns of leaf δ¹³C when we consider China as a whole. Ultimately, we conducted a multiple regression model of leaf δ¹³C with environmental factors and mapped the spatial distribution of leaf δ¹³C in China by using this model. However, this partial least squares model overestimated leaf δ¹³C for most life forms, especially for deciduous trees, evergreen shrubs, and subtrees, and thus need more improvement in the future.