Lagoon and Habitat (EUNIS) fragility to alien species in Mediterranean lagoons.

Lagoons are ecotone ecosystems, naturally exposed to immigration from their freshwater and marine input environments; strictly lagoonal species are rare, if ever occurring, and lagoon community are likely to be organised through lottery competition processes. These evidences suggest the study of lagoons as models address ecosystem fragility to alien species. Here, we present an analysis of lagoon guild fragility to alien species carried out using the e-Science facilities of LifeWatch, the European Research Infrastructure on biodiversity and ecosystem research. The analysis has been performed on two EUNTS habitat (X02 and X03) using data existing on 18 Italian lagoons. The analysis has been carried out taking into account that rarity, redundancy and singularity are key properties of different guilds in lagoon ecosystems at every geographical area, affecting B and y diversity. At every area an high regional biodiversity is determined by a large number of rare species and a high dissimilarity among lagoons. Life cycle traits and the behaviour of larval stages, at the species level, as well as lagoon openness and vigour, at the ecosystem level, seem to have a major role to explain the difference in patterns of biodiversity between study areas at a biogeographical scale. The same species and ecosystem level properties, together with spatial patchiness, seem also to be key factors downscaling biodiversity analysis at the landscape level.