Browsing by Author "St Germain, Michael J."

Now showing 1 - 4 of 4
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    Analysis of Fox Activity and Survival in Foxhound Training Enclosures
    Klopfer, Scott D.; Kramer, David; St Germain, Michael J. (Virginia Tech, 2013-03)
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    Bat Habitat Ecology Using Remote Acoustical Detectors at the Army National Guard Maneuver Training Center - Fort Pickett, Blackstone, Virginia
    St Germain, Michael J. (Virginia Tech, 2012-04-25)
    Bats occupy diverse and unique niches and are regarded as important components in maintaining ecosystem health. They are major consumers of nocturnal insects, serve as pollinators, seed disperser, and provide important economic benefits as consumers of agricultural and forest pest insects. Bats have been proposed as good indicators of the integrity of natural communities because they integrate a number of resource attributes and may show population declines quickly if a resource attribute is missing. Establishing community- and population-level data, and understanding species interactions is especially important in changing landscapes and for species whose populations levels are threatened by outside factors of anthropomorphic disturbance from hibernacular visitation to energy production and fungal pathogens. For these reasons I have set out to establish habitat use patterns, detection probabilities, spatial and temporal occupancy, and investigate species interactions. This thesis is broken down into three distinct chapters each intended to be a stand-alone document. The first establishes the basic ecology from natural history accounts, provides an overview of the various sampling strategies, and gives a comprehensive description of the study area. The seconds sets out to identify the factors influencing detection probabilities and occupancy of six sympatric bats species and provide insight into habitat use patterns. The third examines spatial and temporal activity patterns and investigates species interactions. This study can provide understanding into the secretive and poorly understood patterns of free flying bats across the landscape. It can also deliver useful information to land managers regarding potential changes in landscape practices for the conservation of bat species.
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    Context dependency of disease-mediated competitive release in bat assemblages following white-nose syndrome
    Bombaci, Sara P.; Russell, Robin E.; St Germain, Michael J.; Dobony, Christopher A.; Ford, W. Mark; Loeb, Susan C.; Jachowski, David S. (2021-11)
    White-nose syndrome (WNS) has caused dramatic declines of several cave-hibernating bat species in North America since 2006, which has increased the activity of non-susceptible species in some geographic areas or during times of night formerly occupied by susceptible species-indicative of disease-mediated competitive release (DMCR). Yet, this pattern has not been evaluated across multiple bat assemblages simultaneously or across multiple years since WNS onset. We evaluated whether WNS altered spatial and temporal niche partitioning in bat assemblages at four locations in the eastern United States using long-term datasets of bat acoustic activity collected before and after WNS arrival. Activity of WNS-susceptible bat species decreased by 79-98% from pre-WNS levels across the four study locations, but only one of our four study sites provided strong evidence supporting the DMCR hypothesis in bats post-WNS. These results suggest that DMCR is likely dependent on the relative difference in activity by susceptible and non-susceptible species groups pre-WNS and the relative decline of susceptible species post-WNS allowing for competitive release, as well as the amount of time that had elapsed post-WNS. Our findings challenge the generality of WNS-mediated competitive release between susceptible and non-susceptible species and further highlight declining activity of some non-susceptible species, especially Lasiurus borealis, across three of four locations in the eastern United States. These results underscore the broader need for conservation efforts to address the multiple potential interacting drivers of bat declines on both WNS-susceptible and non-susceptible species.
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    Winter roost selection of Lasiurine tree bats in a pyric landscape
    Jorge, Marcelo H.; Ford, W. Mark; Sweeten, Sara E.; Freeze, Samuel R.; True, Michael C.; St Germain, Michael J.; Taylor, Hila; Gorman, Katherine M.; Garrison, Elina P.; Cherry, Michael J. (2021-02-09)
    Day-roost selection by Lasiurine tree bats during winter and their response to dormant season fires is unknown in the southeastern United States where dormant season burning is widely applied. Although fires historically were predominantly growing season, they now occur in the dormant season in this part of the Coastal Plain to support a myriad of stewardship activities, including habitat management for game species. To examine the response of bats to landscape condition and the application of prescribed fire, 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 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 in real-time. 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 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 during or immediately following burning. In both cases, these bats had day-roosted at heights lower than the majority of other day-roosts observed during our study. Our results suggest Seminole bats choose winter day-roosts that both maximize solar exposure and minimize risks associated with fire. Nonetheless, because selected day-roosts largely were fire-dependent or tolerant tree species, application of fire does need to periodically occur to promote recruitment and retention of suitable roost sites.