Mediterranean temporary pond restoration invcreases bat species richness but not bat activity

Abstract

Climate change scenarios predict a continued decrease in rainfall across the Mediterranean regions in the next years, emphasizing concerns about water scarcity. The ongoing destruction, modification, and drainage of wetland habitats further intensifies this risk to the landscape. Ponds are vulnerable aquatic habitats that supply essential ecosystem services and provide foraging and drinking resources to bats. To enhance the integrity of degraded habitats, restoration actions have been widely implemented, demonstrating positive effects for bat conservation. However, there is a scarcity of long-term studies in aquatic habitats, and none was carried out in ponds. Here, we aim to assess the responses of bat activity and species richness to the restoration of temporary ponds. Such restoration actions involved the digging or deepening Mediterranean temporary ponds aimed at re-establishing the terrain depression to increase the water holding capacity. We hypothesized that these actions promote overall bat activity and species richness in the long term. To evaluate this impact, we monitored the bat acoustic activity for five years (three before and two after the restoration actions) in 16 ponds (six restored and ten control ponds) along the southwestern coast of Portugal. Results from the Before-After-Control-Impact (BACI) analyses revealed a positive impact of restoration on species richness: there were up to 2 more species in the intervened ponds after restoration actions. While many species increased their activity in both pond types, Myotis myotis / M. blythii, Nyctalus leisleri, Pipistrellus kuhlii and Tadarida teniotis demonstrated increases in activity exclusively in the restored ponds. Overall, bat activity also benefited from pond restoration, although its increase is slight, deeming a non-significant change. These outcomes highlight a win-win scenario for bat conservation associated with the restoration of Mediterranean temporary ponds, even considering the ability of bats to use the wider landscape.