Negative trend reversal after 16 years of constant growth: The case of Rhinolophus hipposideros in an Austrian mass hibernaculum (Chiroptera: Rhinolophidae) [Návrat negativního trendu po 16 letech stálého nárustu: případ Rhinolophus hipposideros
Friederike Spitzenberger, Simon Engelberger
The populations of bats hibernating in Hermann’s Cave, Lower Austria, have been intensively studied for almost 160 years. Here we present the population trend of Rhinolophus hipposideros during the period 1985–2013. In contrast to wintering populations in nearby caves in Styria/Austria as well as in neighbouring countries (Czech Republic, Slovakia, Thuringia/Germany), we observed a statistically significant decline since 2007. Maximum numbers of R. hipposideros recorded in the cave were roughly the same (770–850 individuals) in 1856, 1945 and 2007. This indicates that despite environmental degradation which has occurred since 1856, the source area of the wintering population produced similar numbers of lesser horseshoe bats hibernating in Hermann’s Cave as in the period when conditions were favourable.