The 1992 Convention on Biological Diversity in Rio de Janeiro adopted the following definition of biodiversity: “the variability among living organisms from all sources, including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part: this includes diversity within species, between species and of ecosystems.”

The Mediterranean is one of the world’s 34 biodiversity hotspots identified by the non-governmental organisation Conservation International (CI). While it represents only 0.82% of the world’s Ocean surface, it is a major reservoir of marine and coastal biodiversity. 28% of its populations are endemic species, and its 8500 macroscopic organisms make up 7.5% of the world’s marine fauna and 18% of its flora.

However, as elsewhere, human activities are having a massive impact on biodiversity and creating multiple challenges. Habitats are disappearing, pollution is impacting the physicochemical profile of its waters, fish stocks are under pressure and climate change is driving the spread of invasive species.

If plant or animal species are allowed to disappear, the ensuing loss of genetic diversity, food resources and undiscovered medical or industrial potential will be irreversible. It is however important to bear in mind that biodiversity is always evolving. With climate change, new species are appearing in the western Mediterranean without necessarily creating an imbalance in existing ecosystems.

Today, we have more and more solutions for protecting biodiversity, including protected areas, legislation giving special status to our coastlines or to certain species (like Posidonia seagrass, fan mussels or dusky grouper), wastewater treatment and the restoration of shallow coastal waters.