Spatial heterogeneity and environmental drivers of grassland community functional traits in the semi-arid loess small watershed

Plant functional traits can reflect the adaptation strategy of the community to the environment and determine the function of the ecosystem. It is of great significance for vegetation resource management and vegetation restoration to study spatial heterogeneity and environmental drivers of community functional traits at a small watershed scale. Using the typical loess semi-arid grassland watershed in Dingxi, Gansu Province as the research area, we investigated the correlation between the weighted mean of seven functional traits and abiotic environmental factors to identify the key drivers of spatial heterogeneity of functional traits using the method of variance decomposition and redundancy analysis. The results showed that 1) three abiotic factors influenced the spatial heterogeneity of community functional traits. The physical property of soil had the most influence, followed by the chemical property of soil, followed by topographical factors. The correlation between the three groups was strong, indicating that there were interactions among the three groups that affected plant functional traits. 2) The available water in soil, total carbon, available nitrogen, total nitrogen, organic carbon, pH, and the bulk density of soil have significant effects on community functional trait heterogeneity. The available water in the soil is the dominant factor, which indicates that it is the key driving factor of plant functional trait variation in a semi-arid area.