VULnerability of Populations under Extreme Scenarios (VULPES project)

International audience ; Under the ongoing global warming plant species are expected to either adapt locally or migrate to climatically more suitable areas. If no local adaptation or potential migration is possible then the species might become threatened of extinction. VULPES project is exploring the capacity of several mountain tree species to persist in microrefugia. We define a microrefugium as a mountainous habitat that may harbor small or reduced populations of a species during a period where the global climate is unfavorable for a wider geographical range. VULPES focuses on five tree species that are located in mountainous areas in Northern and central Africa (Morocco and Cameroon), Asia (China) and South America (Ecuador and Brazil). The chosen areas are expected to have local climates that deviate from the regional or global climate. The focal species of the project have persisted in situ over several thousands of years, have a fragmented range today, and are considered either as vulnerable or as threatened of extinction according to the IUCN Red List. In this presentation we will use one or two species to illustrate the aim of the VULPES project and provide a brief state of the art. The first species is the Atlas cedar (Cedrus atlantica) in Morocco. A synthesis of fossil pollen records indicates that Atlas cedars occupied in the past a wider range at lower elevations when winter temperatures were lower than today and the water availability was higher. Model simulations confirm that the range of the species decreased tremendously over the last 50 years. In parallel, the modern genetic data obtained from collected material in the field reveal very low divergence between populations, which indicates that the modern populations formed at least one large population which became fragmented in the Moroccan mountains by extinction at lower elevations. Altogether, these three disciplines allow us to evaluate whether the species is capable of persisting in situ or not and the trend of decay of its composing ...