A North African–European transition fauna: water beetles (Coleoptera) from the Ebro delta and other Mediterranean coastal wetlands in the Iberian peninsula

Abstract

1. The aquatic Coleoptera of some major wetlands in the Mediterranean coast of Spain were surveyed, with the aim of assessing their conservation value and the status of some coastal species in the Iberian Peninsula. 2. Classification of 59 species from 13 sites between the deltas of the rivers Ebro and Llobregat using TWINSPAN suggested that water origin and amount and structure of vegetation were major factors influencing the composition of the coastal water beetle communities. 3. The Ebro delta is considered to be a key biogeographical area, being the limit of the distribution of a number of north African and European species. Coastal sites in the Iberian peninsula sustain the only known populations in continental Europe of at least three Ethiopian species, although two of them may have become extinct. Some European species known to have reached the north of Catalonia were also considered to be possibly extinct in the Iberian peninsula owing to the destruction of their habitats. Three circum-Mediterranean coastal species were recorded for the first time in the Iberian peninsula, one of them in a genus new to its fauna. 4. Despite the scarcity of true endemics—the result of the recent geological origin and the temporal dynamics of coastal systems—some species were exclusive to temporary habitats, and had very restricted distributions. 5. Although most of the areas studied have some form of protection, this is mainly focused in large, permanent lagoons and on the vertebrate fauna. The need to include marginal areas and invertebrates in the protection plans for the area is stressed.