Séminaire de Ophélie Ronce 
Institut des Sciences de l'Evolution de Montpellier

• Date : Vendredi 02 février 2024
• Horaire : 9h30
• Lieu : Airial de Pierroton, UMR BioGeCo, Centre INRAE de Cestas

Climate  change is a threat to long-lived trees, which may not adapt or migrate fast enough to keep up with rising temperatures.

Assisted gene flow could facilitate adaptation of populations to future climates by using managed translocation of seeds from a warmer location within the current range of a species. Finding the provenance that will perform best in terms of survival or growth is complicated by a trade-off: because trees face a rapidly changing climate during their long lives, the alleles that confer optimal performance may vary across their lifespan. For instance, trees from warmer provenances that will be well-adapted as adults could suffer from colder temperatures while still in a poorly tolerant juvenile stage. Here we use a stage-structured model to determine which provenance would maximize the survival of a cohort of long-lived trees in a changing climate.

Our mathematical model predicts that the best provenance depends on how fast the climate will change, but also largely on how climatic tolerance of the trees varies across life stages and on the time spent in the least tolerant stage. We parameterize the model with empirically estimated demographic transition matrices for twenty long-lived tree species and show the previous conclusions to be robust to variation in the life cycle of trees. We therefore call for increased empirical effort to measure how climatic tolerance changes across life in long-lived species, which remains unknown for most tree species.