PROJECT DESCRIPTION
BACKGROUND
The expansion of the introduced green alga Caulerpa taxifolia in the Mediterranean sea has continued regularly since 1984. The ecological risk (competition with indigenous ecosystems and modification of the biodiversity) appeared clearly on the basis of research that had been done since 1992. Equally, a risk to exploited resources (fish, sea urchins) was considered, as well as a risk to human health (in case of transmission of toxins along the food-chain).The project aimed to specify the real distribution of Caulerpa taxifolia, to follow its evolution, and to anticipate the ultimate evolution of the phenomenon. In addition, it was advisable to establish the scientific and technological basis of the eradication. This international project was managed with Spanish and Italian partners (universities, local authorities and scientific centers). This programme has shown that: · The expansion of Caulerpa taxifolia is continuing. A precise state of locations and occupied surfaces was studied. · This expansion is threatening the biodiversity : diversity of species (particularly some taxonomic groups such as seaweeds) and diversity of communities (particularly Posidonia oceanica meadow). · The secondary toxic metabolites produced by Caulerpa taxifolia play important roles (directly or indirectly) in its competitiveness to indigenous species. · The eradication of Caulerpa taxifolia is not possible when occupied surfaces are very large (several tens or hundred of hectares). This project was followed up by a Life ENV 95 project.