Drivers of plant intraspecific variation are trait-specific

Summary The importance of intraspecific trait variation (ITV) in community dynamics is increasingly being recognised, but the drivers of ITV have not yet been well-studied. Here, we analysed whether environmental conditions, biotic interactions and species features are related to ITV on a global scale. We compiled a global species’ ITV database including 2064 species which occurred in 1068 communities (plots) across 19 countries with 11 functional traits. The magnitudes of species’ ITV in this database were calculated according to the trait-gradient analysis which is independent of the length of the environmental gradient. We found that different traits had different main drivers, so we consider the drivers of ITV to be trait-specific. However, our findings still brought some order among these idiosyncratic patterns: leaf economics spectrum traits were more related to environmental conditions and leaf morphology traits were more related to biotic interactions. Size-related traits were related to both abiotic and biotic conditions. Our research suggests that the drivers of ITV deviated from the drivers of the mean trait values and that some trait coordination may fall apart upon climate change. Thus, our analysis enhances our understanding of trait variation and has important implications for models predicting vegetation responses to environmental change.