Optimizing Surveys for Imperiled Bat Species Post White-Nose Syndrome

Many bat populations have plummeted in North America since the introduction of white-nose syndrome (WNS) in 2006, presenting challenges in researching population health and habitat use of affected species. Traditional survey techniques such as mist-netting and radio-telemetry have become increasingly time-consuming post-WNS due to the rarity of WNS-susceptible species in affected areas. To address the difficulty of studying imperiled bat species, we explored the use of an acoustic lure alongside mist-netting and acoustic monitoring to potentially enhance species detection in southeastern Missouri, United States. Acoustic lures elicit varying intra- and interspecific behavioral responses; thus, we explored the effects on multiple bat species' encounter rates while using tricolored bat Perimyotis subflavus distress vocalizations. The acoustic lure increased the number of acoustic detections for the federally endangered Indiana bat Myotis sodalis and non-imperiled big brown bat Eptesicus fuscus, and increased captures of the silver-haired bat Lasionycteris noctivagans, a species of conservation concern in Missouri. Additionally, only two individuals of P. subflavus were captured in mist-nets, and both were captured with the acoustic lure. These results suggested that acoustic lures are a valuable tool for identifying the presence of imperiled species when used in combination with mist-netting and acoustic detectors. Researchers studying bat communities that have experienced significant population declines because of WNS or other factors should incorporate multiple survey techniques, including acoustic lures, to increase capture rates and better document species distributions. Doing so should provide more accurate information on the distribution of imperiled bat species, which is relevant to conservation and management.