Toward a mechanistic understanding of climate refugia: fine-scale climatic control of distribution and regeneration in relict beech (Fagus sylvatica) populations in the Aquitaine Bassin (UMR BIOGECO / ISPA)
Climate refugia are areas where local populations of a species can survive through periods of unfavourable regional climate. They have played a critical role for the persistence of biodiversity through past periods of major climatic transitions, suggesting that they could be important in mitigating the impact of future global warming. We lack a clear mechanistic understanding of how refugial environments trigger the viability and regeneration of their inhabitants. The Aquitaine Basin contains 11 known lowland refugia of beech (Fagus sylvatica), a major European forest tree species that is otherwise restricted to mountain ranges in the region. All these beech stands grow along water streams, presumably relying on the particular local climates that these create. The project CLIMBEECH proposes to investigate how these ‘refugial climates’ trigger the presence and performance of Aquitanian beech populations, a fundamental knowledge for predicting how these populations could evolve in a warmer and drier regional climate. We will combine ecological, genetic, ecophysiological and meteorological research approaches to investigate how the particular refugial environment triggers: 1) the fine-scale spatial distribution of beech populations and associated plant communities, 2) spatio-temporal patterns of tree performance and vigour, and 3) spatial patterns of reproduction and seedling recruitment. The project aims at integrating in-depth biological studies with an extensive environmental monitoring and the application of advanced ecophysiological and meteorological modelling. Our combined approach should allow us to achieve a better mechanistic understanding of the fine-scale environmental control of forest tree regeneration within the particular setting of climate refugia.