Date of Award
5-2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Wildlife and Fisheries Biology
Committee Chair/Advisor
Dr. David Jachowski
Committee Member
Dr. Susan Loeb
Committee Member
Dr. Catherine Jachowski
Abstract
North American bat populations continue to be decimated by many factors, with the largest contributor being white-nose syndrome (WNS). In recent years researchers have noted the importance of fat reserves pre- and post-hibernation (fall and spring) and how they may influence WNS survival and recovery respectively. Tri-colored bats (Perimyotis subflavus) are one of the four species most impacted by WNS but have received the least research. Further, thus far all research on tri-colored bat resource selection has been gathered during summer and winter, highlighting the need for habitat selection studies during the fall and spring pre- and post-hibernation periods. To address this concern, we used acoustic detectors and radio telemetry to 1) determine suitable tri-colored bat foraging habitat in northwestern South Carolina during spring and fall, and 2) determine suitable tri-colored bat roosting habitat in northwestern South Carolina during spring and fall.
To investigate suitable foraging habitat, we determined tri-colored bat occupancy at 138 sites in the Sumter National Forest in northwestern South Carolina during spring (March-May) and fall (September-November) 2021 and 2022 using acoustic detectors. We placed acoustic detectors at selected sites for three nights and recorded vegetation structure and landscape data for each site. We evaluated support for the hypothesized importance of forest management, forest structure, forest composition, and landscape features using single season occupancy models. Across both years we detected tri-colored bats at 40 sites in spring and 34 sites in fall. During spring, probability of occupancy declined as percent canopy cover increased. During fall, probability of occupancy increased at sites with past forest management; sites that had previously been burned, harvested, or thinned had greater occupancy than control sites. Our results suggest the importance of forest openings or reduced understory clutter for suitable foraging sites pre- and post- hibernation in northwestern South Carolina.
To investigate suitable tri-colored bat roosting habitat we radio-tracked adult tri-colored bats to roost trees during spring (March-May) and fall (September-November) 2021 and 2022 in the Clemson Experimental Forest and Andrew Pickens Ranger District of the Sumter National Forest in northwestern South Carolina. We characterized roost trees, roost sites, and associated available trees and used discrete choice models to evaluate support for the hypothesized importance of roost tree characteristics and surrounding landscape in tri-colored bat roost site selection. During spring, we located 5 bats on 23 total nights at 14 trees; bats switched roosts on average every 2.0 days. We were not able to locate enough bats for resource selection analysis, however, we determined that bats used multiple roost sites including live pine (Pinus spp.) and oak (Quercus spp.) trees, and their winter hibernacula (old mine). During fall, we located 5 bats on 45 nights at 18 trees; bats switched roosts on average every 2.25 days. Tri-colored bats selected roosts in dominant-codominant hardwood trees that were on northern aspect slopes and within stands that had high levels of forest canopy but lower levels of midstory stem density. Tri-colored bats used multiple roosts within and between seasons, including use of their winter hibernacula. Therefore, it is important to provide multiple roost options, particularly near their hibernacula.
Collectively, our results show that tri-colored bats used multiple roosts and foraged in areas that have reduced vegetation clutter during spring and fall. Thus, management that maintains habitat heterogeneity and mature roost trees on northern slopes with greater surrounding forest canopy but lower surrounding midstory stem density may favor tri-colored bats. Additionally, tri-colored bats may benefit from management that provides foraging habitat around roost sites, particularly management that increases open habitat and reduces vegetation clutter to minimize energy expenditure. Our study highlights the importance of gathering more information on tri-colored bat habitat use and selection during spring and fall to align forest management strategies with tri-colored bat year-round habitat requirements.
Recommended Citation
Rosales, Eduardo, "Tri-colored Bat Habitat Use and Selection In Northwestern South Carolina" (2024). All Theses. 4233.
https://open.clemson.edu/all_theses/4233