The significance of water infrastructures for the conservation of bats in a semiarid Mediterranean landscape

The semiarid Mediterranean areas of south-eastern Spain have undergone great economic growth in recent years following the disproportionate expansion of intensive agriculture and housing developments. Such growth can only be supported by the development of large-scale hydraulic engineering works to compensate for the restrictions imposed by the scarcity of autochthonous water resources. We have studied the role of this type of infrastructure in the habitat use of several bat species in a protected forest area and its surroundings, a mixed landscape of traditional and intensive agricultural landscape crossed by the Tagus-Segura water transfer channel and endowed with frequent irrigation ponds. Our results showed that water infrastructures have a positive effect on bat activity (as measured as bat passes and feeding buzzes per unit time) and species richness. The regression models indicate that bat activity is notably higher in the Tagus-Segura channel than in the other habitat types studied. However, this higher activity appears to be mainly due to the presence of the two most common species, Pipistrellus pipistrellus and Pipistrellus pygmaeus, while others, such as the trawling bats Myotis daubentonii and Myotis capaccinii, specialist hunters in this kind of habitat and under greater threat in the study area are much less frequent. The absence of vegetation along the canal and the speed of the current do not seem to favor the presence of these last two species, whose conservation value is much greater than that of the pipistrelles.