Abstract:
Timber harvesting is an essential tool for bat habitat management on both public and
private lands. Despite a long history of timber harvesting and forest management in the Midwest,
there is a paucity of information regarding the immediate and long-term effects of these practices
on forest dwelling bat species. To better understand the ecological consequences of harvesting
practices on the bat community, we acoustically surveyed 108 sites across the Morgan-Monroe
and Yellowwood state forests in southern Indiana during the 2016-2017 summer seasons (May August). As part of the Hardwood Ecosystem Experiment, a long-term (100 yr.) ecological
study, we used paired random sampling techniques to survey bat occupancy in three different
harvest types including clearcuts, shelterwoods, and single-tree selection, as well as in intact
forest stands. Echolocation calls were recorded using Wildlife Acoustics SM2+ echolocation
detectors and calls were classified using Bat Call ID v.2.7D (BCID) and Echoclass v.3.1. We
recorded between 24,552-37,672 bat calls, of which we classified 14,039-19,690 to specific
species depending on automated classifier. We used single-season false-positive occupancy
models to estimate bat occupancy across a gradient of harvest intensity for single species as well
as relative call frequency groups. Indiana bats (Myotis sodalis), big brown bats (Eptesicus
fuscus), little-brown bats (Myotis lucifugus), and eastern red bats (Lasiurus borealis) showed
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negative relationships with increasing basal area while northern long-eared bats (Myotis
septentrionalis) showed positive relationships with increasing basal area. Predictors of bat
occupancy varied across species and included basal area, distance to nearest road, and distance to
nearest wildlife pond. Overall, we found differences in occupancy in forest stands differing in
basal area and limited evidence that occupancy is better predicted by single-species models than
by frequency group models. Our results can be used to aid in future management decisions
regarding the effects of timber harvesting on the bat community
