Species specific effects of prescribed burns on bat occupancy in northwest Arkansas

Abstract

Due to the recent spread of white nose syndrome, it is imperative that managers understand the effects their management techniques have on bat species. Our research aims to determine the spatial and temporal variation in occupancy of bat species native to the Ozark Highlands and Boston Mountains of northwest Arkansas. Although prescribed burn units in this region are burned on a three-year rotation, it is not currently known how this treatment schedule affects bats. To determine the effects of prescribed burns on bat species including Myotis grisescens, Nycticeius humeralis, and Perimyotis subflavus, acoustic monitors and insect traps were deployed at 20 burned and 20 unburned sites that were visited twice, between April and November of 2017. Bat calls were analyzed for presence/absence data. Single season occupancy modeling was used to determine the effects of environmental covariates on probabilities of detection and occupancy. In total, 132,528 acoustic files were collected. The probability of detection for each bat species was affected by temperature or moon phase. Occupancy models indicated that probability of occupancy for all species was affected by seasonal changes and basal area (m2/Ha), and all but one were affected by prey biomass. These data indicate that although prescribed burns may have not directly affected bats, potential indirect effects of fire, basal area and insect biomass, appear to have significant impacts.