Bat activity over small ponds in dry Mediterranean forests: implications for conservation

In dry Mediterranean forests, ponds constitute essential water resources for animals, especially during summer months. In southeastern Spain, land use changes and the human abandonment of mountainous zones have led to the loss of many ponds. These ponds are scarce landscape elements and, despite their usually small size (< 1,000 m(2)), they support a considerable amount of biodiversity. We studied the patterns of use of these ponds by bats during the activity season in dry forest landscapes of a Mediterranean region using acoustic monitoring. Our hypothesis was that these ponds are valuable landscape elements for bats, and bat activity and richness species will be high over them. Bat activity and species richness were compared between ponds and adjacent sampling points in the forest matrix. We recorded 14 bat species and our results show that both general bat activity (all species grouped together) and species richness were higher in the ponds than in the forest areas. Bat activity was higher in June, however it decreased during drier months (July-August), while activity in the forest increased. The number of species was constant in the areas surrounding the ponds through the study period, but in the forest we observed an increase in July and a gradual decrease in August-September. Similar results were obtained for most individual species, although in some species activity was also influenced by temporal variables. Our study shows that the maintenance of small ponds may have important consequences for bat conservation, as they support high bat diversity, including some species of conservation concern like horseshoe bats (Rhinolophus spp.) or Myotis spp.