Climate change and the future of endemic flora: a case study from the centre of endemism of South Western Alps

Climate change is a major threat to biodiversity, particularly in mountain ecosystems, which are often important centres of endemism. However, climate change effects are mainly studied on widely distributed taxa. Using species distribution model, we assessed the climate change impact on endemic flora of the richest centres of endemism in the Alps: South Western Alps. Assuming realistic dispersal abilities, we projected the species potential distributions (year 2070) using both an optimistic and a pessimistic scenario. Moreover, we explored the differences among vegetation belts and niche properties. Overall, high range loss and low range gain were predicted for all species, determining a strongly negative range change, mainly caused by dispersal limitation. Nevertheless, the predicted extinction rate was low. Mountain and subalpine species resulted more threatened by climate change than colline species, which are already experiencing dry and warm climate. Moreover, the relationship between range loss and niche properties vary among vegetation belts. The lowest range loss was predicted for specialist (termophilous) species in colline belt and for generalist species in mountain and subalpine belts. Altogether, these results suggest that the distribution pattern of this endemic flora will deeply change in the future, despite its overall species composition will be little affected by climate change. Particularly, those species that currently occupy environmental conditions toward which the climate of the study area is expected to move in the future seem less prone to climate change. These result underline the urgency of elaborating conservation strategies focused on mountain and subalpine taxa.