Climate change and the evolutionary challenge of Mediterranean biodiversity

Abstract

The Mediterranean basin is a region of high biodiversity, marine and terrestrial, with important endemism. This diversity has faced long-lasting, strong and increasing human demographic pressure. The relatively more recent effects of climate change are well visible in the Mediterranean basin, with for example, heat wave and summer-drought related mortality on various species and ecosystems. The Mediterranean is then a model region for studying the consequences of climate change on biodiversity. Climate change, combined with land use change, may prove a particularly daunting adaptive challenge in the evolutionary, geomorphological and biogeographical context of the Mediterranean Basin. This semi-enclosed sea, its position and the succession of mountains and valleys over short distances, will limit range shift for both marine and terrestrial species. Millennia-old habitat destruction, fragmentation and abandonment of agriculture, urbanization, overharvesting and species introduction, will impact the evolutionary range and trajectories of marine and terrestrial species. We will discuss the potential of adaptation to climate change in Mediterranean ecosystems on the basis of studies on ecologically relevant terrestrial and marine species. After presenting the different modes of biological adaptation (acclimation and genetic adaptation), we will show how recent results, integrating genetics and ecology, allow to estimate the adaptive potential of these species. We will discuss the biological and ecological characteristics of these organisms which might favor or limit future adaptations, and the potential consequences on Mediterranean socio-ecosystems. We will consider terrestrial and marine ecosystems, such as forests and coralligenous habitats, as well as the interactions between land and sea. The social consequences, and the corresponding need to adapt management strategies, will also be taken into account.