Guide to the freshwater molluscs of the Lesser Antilles

Biological invasion is one of the major problems in tropical ecosystems. The freshwater ecosystems of the Lesser Antilles are no exception, and the mollusc fauna provides numerous examples of invaders. Interestingly large-scale and fast change in these ecosystems, including eutrophication, paved the way to a build-up of species diversity: the number of species about doubled over the last 50 years with about 31 species now, and brand-new communities have arisen. These introductions have been extremly well documentedin Martinique and Guadeloupe, showing that new species are arriving almost on a yearly basis. In the case of the Lesser Antilles, bioinvasions therefore led to anaccumulation of biodiversity rather than an erosion. It should also be highlighted that some of the mollusc newcomers are potential vectors of human and cattle disease. It is therefore of prime importance to be able to identify mollusc species as precisely as possible, not only to evaluate epidemiological risk, but also to show the dynamics of freshwater snail communities in their ecosystems. This guide should be helpful in this respect.