Long term trends of hibernating bats in North-Western Italy

(Uploaded by Plazi for the Bat Literature Project) Several species of bats have faced strong population declines in Europe during the last century. However, an increase in some bat populations has been recently found in some parts of western Europe. We monitored wintering bats in the underground caves of north-western Italy (Piedmont, Valle d'Aosta and Liguria regions), with the aim of estimating long-term population variations. Over 28 years (from 1992 to 2019), 52 hibernation sites were monitored where 14 species of bats were present. Altogether, 97% of individuals belonged to Rhinolophus euryale, Rhinolophus ferrumequinum, Rhinolophus hipposideros, Barbastella barbastellus, Myotis emarginatus, and to the large Myotis group (Myotis myotis/blythii). We found a positive population trend for these six most common species with an average annual increase ranging between 3.5% (R. ferrumequinum) and 15.0% (B. barbastellus), which is in congruence with what has occurred in central and western Europe in the last 20 years. The species R. hipposideros showed a significant increase during the first 10 years, followed by a stable trend thereafter.