Format: ORAL

Jos Alberto Ramrez-Valiente1,2, Antoine Kremer3

1 Institute of Forest Science, INIA-CSIC, Madrid, Spain 2 CREAF, Barcelona, Spain 3 BIOGECO, INRAE, Bordeaux, France

One of the main questions in evolutionary biology is whether populations can evolve in response to the ongoing climate change. Understanding past evolutionary trajectories might help us to predict present and future responses. In this review, we aim to identify the main climatic drivers of selection, to detect key traits for adaptation to climate heterogeneity and evaluate the evolutionary potential of forest tree species in response to contemporary climate change. Results from phenotypic selection studies at different temporal and spatial scales report that leaf traits, particularly those related to morphology and physiology are under significant selection. Consistently, a meta-analysis on common garden experiments showed widespread population divergence across species in growth, phenology, leaf economics and allometry. Associations with climate, however, strongly differed across biomes. In general, temperature is the main driver of population divergence in temperate environments whereas precipitation is the main driver in seasonally-dry tropical ecosystems. In Mediterranean environments, both temperature and precipitation have had important roles in population evolution but acting on different traits. Specifically, whereas phenology and growth have evolved in response to minimum temperatures in winter, leaf morphology and leaf economics have evolved in response to precipitation. Studies combining phenotypic and genomic data show that estimated ancestral populations tend to exhibit more conservative resource-use strategies which would provide evidence of adaptation to a colder environment in the past. Synchronic studies also support the existence of evolutionary responses to contemporary climate changes (less than 500 years) in growth, phenology and leaf physiology consistent with population studies and phenotypic selection analyses. Overall, our results suggest high evolutionary potential in forest tree species that has allowed them to respond recent climate fluctuations. However, further studies are needed to elucidate the pace of evolution, particularly through multivariate perspectives that assess trait integration within phenotypes.