Effects of White-Nose Syndrome on the Bat Population in Land Between the Lakes

A rapid decrease in bat populations is occurring in eastern North America due to the emergence of Pseudogymnoascus destructans (A. Gargas), the causative agent of white-nose syndrome (WNS). WNS affects cave-dwelling species, causing mortality during winter hibernation. Substantial declines in bat abundance in Kentucky during summer were first apparent in 2014, although infected bats were first detected in the state in 2011. We investigated the impact of WNS on bat populations in Land Between the Lakes by comparing historical bat survey data (1994-2005) with data from summer 2015. We compared the abundance of WNS-susceptible species with non-susceptible species. Capture rates of susceptible species that were abundant pre-WNS (i.e., Eptesicus fuscus (Beauvois), Myotis septentrionalis (Trouessart), Perimyotis subflavus (F. Cuvier)) declined by 60-87%. Capture rates of males and females of WNSsusceptible species were reduced substantially in July 2015 compared with July 2005, with the decline greatest for males. Among age classes, capture rates of adults and juveniles in July declined by at 30% and 76%, respectively, for WNS-susceptible species between 2005 and 2015. Capture rates of non-susceptible species were stable for Lasiurus borealis (Muller) and increased by over 100% for Nycticeus humeralis (Rafinesque). Males may be more vulnerable to WNS because they carry smaller fat stores during hibernation and, therefore, are more likely to exhaust their energy reserves when infected with P. desctructans. The increase in capture rates of N. humeralis suggests that the species may be exhibiting competitive release and niche expansion as WNS-susceptible species decline