Long term trend of an endangered bat species in north-western Italy

Abstract

Thirty three maternity roosts of Rhinolophus hipposideros were monitored from 2000 to 2018 in an area of north-western Italy, between the Piedmont (13 roosts) and Liguria regions (20 roosts), and data were analysed through a TRIM statistic to calculate a robust estimation of reproductive population trends. Throughout the 19-years-long monitoring period, a total of 5135 Rhinolophus hipposideros were counted in maternity roost, with a mean of 273 (SD = 198.1) per year (mean Piedmont = 73, SD = 85.9; mean Liguria = 200, SD = 164.6). The population analysis model shows a significant overall gradient of 1.047, which corresponds to an average annual increase of 4.7 % over the period considered. The analysis suggests that in the study area, the reproductive population of Rhinolophus hipposideros monitored in the maternity roost has increased throughout the period from 2000-2018, with large increases after 2010 and different trends occurring in the two regions considered, including a significant moderate increase in Liguria and a stable trend in Piedmont. The results agreed with the recently observed trends in other European countries for this species.