Influences of habitat and temperature on winter bat assemblages

Abstract

In temperate North America, insectivorous bats face unprecedented threats because of white-nose syndrome, wind-energy development, and habitat loss. Thus, understanding the natural and life histories of bats is imperative for their conservation. While much effort has been placed on the conservation of bats, especially reproductive females, during summer, the behaviors of bats at other times of year are understudied. Winter presents unique challenges for insectivorous bats as low temperatures lead to high thermoregulatory costs and reduced prey availability. While many bats cope with these conditions by migrating or hibernating, some bats, especially at more southern latitudes, remain active throughout the winter. With their ability to enter torpor, these bats can persist throughout winter, fluctuating between active and inactive states to conserve energy until more favorable weather conditions arise. In this thesis, I use acoustic monitoring equipment to monitor the winter activity of bats across a managed pine landscape in the South Central Plain ecoregion of central Louisiana and eastern Texas. I aim to address two aspects of bat ecology in winter. In chapter 2, I assess how the bat assemblage responds to temperature, including how overall bat activity changes, whether species-specific temperature thresholds exist, and if species richness corresponds to temperature. In chapter 3, I investigate the habitat selection by bats in winter. With bats having limited food resources but not being limited in their selection by reproduction, I predict that bats will not exhibit habitat selection during winter and will instead occur across the landscape. This information is imperative for filling the knowledge gap in winter bat activity and address the need for implementing year-round conservation for the proper protection of bat populations in North America.