Marine Species Introduced on the French Channel-Atlantic Coasts: A Review of Main Biological Invasions and Impacts

Abstract

The impacts of anthropogenisation modify permanently the distribution patterns of brackish and marine species. Globalization leads to a rapid increase of the numbers of introduced species any-where in the world. Biological invasions often result in significant losses in the economic value, biological diversity and function of invaded ecosystems. This review presents the main pathways of introduction of non-indigenous species and the main benthic taxonomic groups being estab-lished and/or invasive along the French Channel-Atlantic coasts. A focus is put on main invasive marine species in the intertidal and subtidal zones of Brittany (France), among macroalgae (Sar-gassum muticum, Grateloupia turuturu, Undaria pinnatifida, Codium fragile and Gracilaria ver-miculophylla), halophytes (Spartina alterniflora) and benthic invertebrates (Mollusks: Crepidula fornicata, Crassostrea gigas and Venerupis philippinarum). The species biology, introduction vec-tors, reproductive and dispersal capacities are considered, together with proliferation patterns along the Channel-Atlantic coasts. The ecological impacts of these species on the environment are also described, as well as the European regulations existing to limit alien species introduction and some examples of struggle against the invaders including eradication trials and biomass valoriza-tion. Last, the on-going impacts of global changes on alien species invasiveness along the Channel-Atlantic coasts are discussed.