Conservation of freshwater biodiversity:: a comparison of different area selection methods

The biodiversity of freshwater systems is endangered, especially in Mediterranean semiarid areas such as the south east of the Iberian Peninsula, whose rich and endemic biota is threatened by the development of surrounding land-crop irrigation. For this reason, the prioritization of areas for biodiversity conservation is an urgent target. In this study we used data records of water beetles from a province of the southeast of Spain for assessing priority areas for freshwater biodiversity conservation. We compare the performance of various area-selection methods, ranging from scoring procedures to complementarity-based algorithms, which are based on different criteria such as richness, rarity and vulnerability. The complementarity approaches were more efficient than methods using scoring or richness and rarity hotspots for representing conservation targets in a given number of areas and for identifying the minimum set of areas containing all species at least once. Within these, the richness-based algorithm was more efficient than rarity-based algorithm. Crucial target habitats for aquatic biodiversity conservation in the area studied are streams at medium altitude, hypersaline streams, and endorreic and karstic complexes.