Introduction to mediterranean forest systems: mediterranean basin

Chapitre 2; All around the Mediterranean, forest systems have been shaped by long-term anthropogenic impacts. Today, they provide multiple goods and services. We show how the social-ecological system approach offers a good framework to understand their biodiversity, functioning and dynamics. Mediterranean forests have a huge biodiversity, not only in terms of the number of species but also in terms of within-species genetic diversity (at least tree species). We present a tentative typology of Mediterranean forests regarding this biodiversity. Then, we explain how the dynamics of Mediterranean forests is driven in particular by a combination of three characteristics: specific environmental constraints (mainly summer water deficit), a marked spatial heterogeneity of the environment at all scales, disturbance regime (e.g. fire, droughts, pest attacks, human pressure) of variable intensity and frequency. The future challenges for the Mediterranean forests will be to respond simultaneously to: (i) increased threats related to climate change and human pressure, (ii) new demand for multiple ecosystem services locally, (iii) emerging interest for Mediterranean resources to support adaptive strategies in other regions.