Biogeography and conservation of Iberian water beetles

An analysis is made of the main biogeographical trends and the conservation status of the aquatic Coleoptera from the Iberian peninsula. More than 600 species in 100 genera and 20 families are recognised, although knowledge o f some of them is still scarce. Overall, the level of endemism is about 20% , with a highly uneven taxonomic distribution. Five main geographical regio ns are recognised based on geological and topographical criteria: Pyrenean, Cantabrian mountains, Hercynian, South East, and South West. These regions have a significantly distinct fauna when all species, species of the famil y Hydraenidae, all Iberian endemics, and Hydraenidae endemics are considere d. For other groups this geographical division is not relevant, as the spec ies follow a random distribution. The main biogeographical division is betw een the northern and the southern regions, with closer similarity between t he Pyrenees and France, and between the South East and Morocco, than with o ther Iberian regions. The conservation status of the species included in th e IUCN red list is reviewed. suggesting the exclusion of three species prev iously considered to be endangered or vulnerable, and the inclusion of two new species as vulnerable. The status of the rare species is discussed, wit h the distinction between local endemics, possible relict species, and spec ies with discontinuous distributions due to habitat loss or habitat fragmen tation. The habitats with the highest conservation value are medium altitud e freshwater streams in the Hercynian mountains of central and western Iber ia, the pre-Pyrenees and the Baetic cordilleras, together with saline strea ms in the South East and the central Ebro Valley. Some general guidelines a re suggested for their preservation. (C) 2000 Elsevier Science Ltd. All rig hts reserved.