Trade-offs between averages and intra-individual variation within vegetative, phenological, and floral traits

O_LIIntra-individual trait variation in plants represents an often ignored but important dimension of phenotypic variation that contributes to functional diversity and the dynamics of ecological communities. It can be expressed differently across plant traits, but the induction of intra-individual variation in different trait types under environmental stresses has not yet been explored. C_LIO_LIWe used the clonal forest herb, Galium odoratum, to investigate intra-individual variation within vegetative, phenological, and floral traits, and trade-offs between trait average and variation under a full-factorial experimental design using drought and shading treatments. C_LIO_LIIntra-individual variation (expressed as CV) differed in magnitude between trait types, with vegetative and floral traits showing the highest and lowest CV, respectively. CV occurring in the different traits responded to the drought and shade treatments. Trade-offs between CV and trait averages appeared across most of traits under the different treatment combinations, whereas trade-offs were less pronounced under control conditions. C_LIO_LIDrought and shading in forest environments induce trade-offs between intra-individual variation and the average trait expression, indicating the relevance of intra-individual variation for functional adaptations of forest plants to climatic changes. Our findings suggest that plastic responses in intra-individual variation may be an important component for mechanistic adjustments of plants to environmental stresses. C_LI