Winter Roost Selection of Lasiurine Tree Bats in a Pyric Landscape

Day-roost selection by tree bats during winter and their response to dormant season fires is poorly known throughout much of the southeastern United States. In the winter of 2019, we mist-netted and affixed radio-transmitters to 16 Lasiurine bats, primarily Seminole bats (Lasiurus seminolus) at Camp Blanding Joint Training Center in northern Florida. We then located day-roost sites to generally describe roost attributes. For five Seminole bats, one eastern red bat (Lasiurus borealis), and one hoary bat (Lasiurus cinereus), we applied prescribed burns in the roost area to observe bat response. Generally, Seminole bats selected day-roosts in mesic forest stands with high mean fire return intervals. At the roost tree scale , Seminole day-roosts tended to be larger, taller and in higher canopy dominance classes than surrounding trees. Seminole bats day-roosted in longleaf (Pinus palustris), slash (Pinus elliotii) and loblolly pine (Pinus taeda) more than expected based on availability, whereas sweetbay (Magnolia virginiana), water oak (Quercus nigra) and turkey oak (Quercus laevis), were roosted in less than expected based on availability. Of the seven roosts subjected to prescribed burns, only one male Seminole bat and one male eastern red bat evacuated the day-roost during or after burning. In both cases, these bats had day-roosted at heights lower and in trees smaller than the majority of other day-roosts observed during our study. Although fires historically were predominantly growing season, they now occur in the dormant season in this part of the Coastal Plain, our results possibly suggest Seminole bats choose winter day-roosts that both maximize solar exposure and minimize risks associated with fire. Nonetheless, at least for Seminole bats, because selected day-roosts largely were fire-dependent or tolerant species, application of fire does need to periodically occur to promote recruitment and retention of these tree species.