The Mediterranean eco-region
The Mediterranean eco-region is one of the 233 eco-regions with outstanding biodiversity at a global scale. Located in the Northern Hemisphere subtropical zone, between 28 and 45 degrees, the Mediterranean eco-region extends from the Atlantic Coast to the Caspian Sea and from the mountain ranges of the Alps to the Saharan desert. This eco-region covers the lands surrounding the Mediterranean Sea, on the three continents of Africa, Europe and Asia and constitutes a unique mosaic of terrestrial, freshwater and marine ecosystems. The rich natural landscape of the Mediterranean is a result of a distinct regional climate imprinted on a dynamic topography.
The climate is the main factor that shapes the physical environment in the Mediterranean. Yearly rainfall varies from 100 to more than 2500 mm while the average temperature ranges from 5 to 20 °C. The existence of an intense summer drought period is the prevalent feature of Mediterranean climates at a global scale. The rich biodiversity of the Mediterranean flora results from the adaptation to the climatic conditions and particularly, to the characteristic water shortage conditions during the dry summer period.
The biodiversity importance of the Mediterranean Eco-region is tremendous1, and is considered one of the primary 11 global biodiversity hotspots, areas of exceptional biodiversity value exhibiting high endemism. Mediterranean flora is extremely rich with around 25.000 vascular plant species. The large number of endemic genus (150) and species (13.000), have a wide distribution throughout the diverse ecosystems of the region. The following table is indicative of the richness of Mediterranean flora:
The 11 most significant biodiversity hotspots according to plant endemism2
On a finer scale, several attempts have been made to identify the most significant "biodiversity hotspot areas", within the Mediterranean Eco-region, based on several taxonomic criteria. Among the most important attempts are: the Centres of Plant Diversity, identified by WWF/IUCN; The Hotspot Analysis For Conservation Of Plant Diversity by the Laboratory of Mediterranean Botany and Ecology (University of Marseilles); the identification of Important Bird Areas (IBAs), by Birdlife International and the Mediterranean Hotspots for Coastal Zone Globally Endangered Species, by La Tour du Valat/GEF. Attempts have also been undertaken at a national level such as the identification of Sites d' Interêt Biologique et Ecologique (SIBE), by the Eaux et Fôrets Service of the Ministry of Agriculture in Morocco. Finally, WWF has conducted its own efforts to refine the identification of Important Forest Areas in the Mediterranean Forest and Shrubland Eco-region and Priority Sites for Marine/Coastal Biodiversity Conservation in the Mediterranean, through a gap analysis approach. The partnership process between the European Union and non EU Mediterranean countries has officially recognised the importance of the «hotspot approach», by considering it as one of the five priorities within its Short and Medium-Term Environmental Action Programme (SMAP)3.
In general, Mediterranean forest ecosystems constitute mosaic-like landscapes, which reflect the complex climatic and geomorphological conditions of regional landforms. Human influence has also intensively modified the natural structure and distribution of forest ecosystems. The high diversity of Mediterranean forests, woodlands and "maquis4" habitat types, characterised by a high number of canopy species, falls within the following broad categories:
2 Source: Mittermeier, R.A. Myers, N. Thomsen, J.B. Da Fonseca, G.A. Olivieri, S. "Biodiversity Hotspots and Major Tropical Wilderness Areas: Approaches to Setting Conservation Priorities", Conservation Biology, Vol 12, No 3, June 1998