EVALUATING RELATIONSHIPS BETWEEN BATS AND LANDSCAPE CHARACTERISTICS IN A WHITE-NOSE SYNDROME POSITIVE REGION: DOES URBANIZATION PLAY AN IMPORTANT ROLE?

Abstract

White-nose Syndrome (WNS) is a cascading disease process, initiated by a skin fungus, killing most cave bat populations across North America. WNS severity differs with the ecology of both the pathogen and the bat species host. This study aimed to identify the habitat features most related to cave bat species by surveying cave bats and habitat features across the urban-rural gradient in Maryland. Our understanding of cave bat ecology in Maryland has changed recently due to technological advancements, though prominent gaps still exist in the urbanized Piedmont and Coastal Plain provinces. As such, a novel urban definition was created to allow research sites to well represent each level of the gradient, and sites were surveyed in random order during four seasons from 2015 to 2017. We found unique results when analyzing predator-prey correlations at weekly scales as well as nightly generalized linear mixed models (GLMM) of habitat usage. At both temporal scales, big brown (Eptesicus fuscus) and tri-colored bat (Perimyotis subflavus) activity were higher at urban than suburban sites. While analyzing predatory-prey correlations at the weekly level, big brown bat activity was highly related to their preferred prey counts at urban sites, while tri-colored bat activity correlated to their preferred prey counts at rural sites. Tri-colored bat activity also occurred at sites during seasons that supported less activity by big brown bats. When analyzing habitat features at the nightly level using GLMMs, in suburbia, big brown bat activity appeared most related to their preferred prey and taller trees. Meanwhile, tri-colored bat activity still held a strong relationship with prey at rural sites across multiple seasons. Big brown bats may select suburbia for roosting and foraging while tri-colored bats may select rural settings for foraging. Interestingly, prey were most abundant at rural sites, indicating rural settings may support higher habitat quality along the gradient. Possible reasons for the seemingly spatial and temporal partitioning by these two species included differing resource availability and some form of niche partitioning. Repeated acoustic surveys and telemetry studies across spatial and temporal scales are recommended to aid bats in greatest need during WNS.