Restoration of Legacy Trees as Roosting Habitat for \u3cem\u3eMyotis\u3c/em\u3e Bats in Eastern North American Forests

Most eastern North American Myotis roost in forests during summer, with species forming maternity populations, or colonies, in cavities or crevices or beneath the bark of trees. In winter, these bats hibernate in caves and are experiencing overwinter mortalities due to infection from the fungus Pseudogymnoascus destructans, which causes white-nose syndrome (WNS). Population recovery of WNS-affected species is constrained by the ability of survivors to locate habitats suitable for rearing pups in summer. Forests in eastern North America have been severely altered by deforestation, land-use change, fragmentation and inadvertent introduction of exotic insect pests, resulting in shifts in tree distributions and loss of large-diameter canopy-dominant trees. This paper explores patterns in use of tree roosts by species of Myotis across Canada and the United States using meta-data from published sources. Myotis in western Canada, the Northwest, and Southwest selected the largest diameter roost trees and also supported the largest maximum exit counts. Myotis lucifugus, M. septentrionalis and M. sodalis, three species that inhabit eastern forests and which are currently experiencing region-wide mortalities because of WNS, selected roosts with the smallest average diameters. Recovery efforts for bark- and cavity-roosting Myotis in eastern North American forests could benefit from management that provides for large-diameter trees that offer more temporally-stable structures for roosting during the summer maternity season

A Survey of Bats in Wayne National Forest, Ohio

Author Institution: Ohio Cooperative Wildlife Research Unit, The Ohio State UniversityDistribution, abundance, habitat selection, and activity of bats in Wayne National Forest, Ohio, were studied during the winters and summers of 1979 and 1980. Methods included winter surveys of abandoned mines and mist netting of riparian sites in summer. Four species of bats were found hibernating in 23 of 65 coal mine shafts examined, and big brown bats, Epteskus fuscus, were most abundant. Mines with long tunnel systems had significantly higher temperatures than those with shorter systems, but humidity did not differ between mine types. Big brown bats chose the cooler mines and in general showed the greatest tolerance of climatic extremes. Eight species of bats totaling 261 individuals were captured by mist netting at 163 riparian locations in 5 watersheds. Little brown bats, Myotis lucifugus, comprised 56% of all bats captured. Big brown bats (14%), eastern pipistrels, Pipistrellus subflavus (13%), and red bats, Lasiurus borealis (13%), were the next most abundant species in mist net samples. No Indiana bats, Myotis sodalis, were captured. Big brown bats preferred to forage in forested habitats. Activity for most species was highest soon after sunset, but activity in big brown bats peaked 0.5 hr later than in the other species

Effects of Reproductive Condition, Roost Microclimate, and Weather Patterns on Summer Torpor Use by a Vespertilionid Bat

A growing number of mammal species are recognized as heterothermic, capable of maintaining a high-core body temperature or entering a state of metabolic suppression known as torpor. Small mammals can achieve large energetic savings when torpid, but they are also subject to ecological costs. Studying torpor use in an ecological and physiological context can help elucidate relative costs and benefits of torpor to different groups within a population. We measured skin temperatures of 46 adult Rafinesque\u27s big-eared bats (Corynorhinus rafinesquii) to evaluate thermoregulatory strategies of a heterothermic small mammal during the reproductive season. We compared daily average and minimum skin temperatures as well as the frequency, duration, and depth of torpor bouts of sex and reproductive classes of bats inhabiting day-roosts with different thermal characteristics. We evaluated roosts with microclimates colder (caves) and warmer (buildings) than ambient air temperatures, as well as roosts with intermediate conditions (trees and rock crevices). Using Akaike\u27s information criterion (AIC), we found that different statistical models best predicted various characteristics of torpor bouts. While the type of day-roost best predicted the average number of torpor bouts that bats used each day, current weather variables best predicted daily average and minimum skin temperatures of bats, and reproductive condition best predicted average torpor bout depth and the average amount of time spent torpid each day by bats. Finding that different models best explain varying aspects of heterothermy illustrates the importance of torpor to both reproductive and nonreproductive small mammals and emphasizes the multifaceted nature of heterothermy and the need to collect data on numerous heterothermic response variables within an ecophysiological context

Effect of Reclamation Technique on Mammal Communitites Inhabiting Wetlands on Mined Lands in East-Central Ohio

Author Institution: Department of Forestry, University of Kentucky; Wildlife Technology Program and Department of Biology, The Pennsylvania State UniversityMammal communities were studied from May through August, 1988 to 1990, at four wetland sites in Coshocton and Muskingum counties, OH. Sites represented varying degrees of disturbance from mining activity and subsequent reclamation techniques, including a wetland constructed to treat mine water drainage. Each site was composed of a series of three cattail (Typba latifolid) cells for a balanced experimental design. Mammals were inventoried with snap trap removal grids and midday surveys for signs of activity. Mammal diversity and richness was highest at the constructed wetland and lowest at the site established with traditional reclamation procedures. Predictable patterns of land use disturbance for species presence/absence were observed with some alpha diversity (habitat specific) species being absent (i.e., tree squirrels) and gamma diversity (wide-ranging) species such as mustelids occurring rarely. Beta diversity species (habitat generalists) like woodchucks (Marmota monax) and white-tailed deer (Odocoileus virginianus) were common at all sites. The white-footed mouse (Peromyscus leucopus) was the small mammal captured most frequently, being the most abundant small mammal at the constructed wetland and the undisturbed site, with meadow voles (Microtus pennsylvanicus) most prevalent at the remaining sites. These results suggest that a wetland constructed for the treatment of mine water drainage can provide secondary benefits as habitat for a variety of mammal species

Shifts in Assemblage of Foraging Bats at Mammoth Cave National Park Following Arrival of White-Nose Syndrome

The arrival of white-nose syndrome (WNS) to North America in 2006, and the subsequent decline in populations of cave-hibernating bats have potential long-term implications for communities of forest-dwelling bats in affected regions. Severe declines in wintering populations of bats should lead to concomitant shifts in the composition and relative abundance of species during the staging, maternity, and swarming seasons in nearby forested habitats. We examined capture rates of bats collected in mist nets from 2009 to 2016 to evaluate summer patterns in abundance of species pre- and post-arrival of WNS to Mammoth Cave National Park, KY. The data demonstrated a significant change in overall relative abundances. Myotis septentrionalis (Northern Long-eared Myotis) was the most commonly captured species pre-WNS but declined to 18.5% of its original abundance. Nycticeius humeralis (Evening Bat), uncommonly caught in mist nets pre-WNS, demonstrated the largest increase in capture success following arrival of WNS to the Park, followed by Eptesicus fuscus (Big Brown Bat) and Lasiurus borealis (Eastern Red Bat). These data suggest that losses of cave-hibernating bats to WNS may be leading to a restructuring of foraging bat assemblages in nearby forested habitats, with species less affected by WNS potentially exploiting niche space vacated by bats succumbing to infection with WNS

Frequent arousals from winter torpor in Rafinesque\u27s big-eared bat (Corynorhinus rafinesquii)

Extensive use of torpor is a common winter survival strategy among bats; however, data comparing various torpor behaviors among species are scarce. Winter torpor behaviors are likely to vary among species with different physiologies and species inhabiting different regional climates. Understanding these differences may be important in identifying differing susceptibilities of species to white-nose syndrome (WNS) in North America. We fitted 24 Rafinesque’s big-eared bats (Corynorhinus rafinesquii) with temperature-sensitive radio-transmitters, and monitored 128 PIT-tagged big-eared bats, during the winter months of 2010 to 2012. We tested the hypothesis that Rafinesque’s big-eared bats use torpor less often than values reported for other North American cave-hibernators. Additionally, we tested the hypothesis that Rafinesque’s big-eared bats arouse on winter nights more suitable for nocturnal foraging. Radio-tagged bats used short (2.4 d ± 0.3 (SE)), shallow (13.9°C ± 0.6) torpor bouts and switched roosts every 4.1 d ± 0.6. Probability of arousal from torpor increased linearly with ambient temperature at sunset (Pn = 86) of arousals occurred within 1 hr of sunset. Activity of PIT-tagged bats at an artificial maternity/hibernaculum roost between November and March was positively correlated with ambient temperature at sunset (PCorynorhinus species with an ecological and physiological defense against the fungus causing WNS, and that these bats may be better suited to withstand fungal infection than other cave-hibernating bat species in eastern North America

Prey Size and Dietary Niche of Rafinesque\u27s Big-Eared Bat (\u3cem\u3eCorynorhinus rafinesquii\u3c/em\u3e)

Bats in the genus Corynorhinus possess a suite of morphological characters that permit them to effectively use both gleaning and aerial-hawking foraging strategies to capture Lepidoptera. Consequently, they occupy a specialized feeding niche within North American bat assemblages and are of particular interest for dietary studies. We collected fecal pellets from a colony of C. rafinesquii (Rafinesque\u27s Big-Eared Bat) at Mammoth Cave National Park during August–October 2011 and amplified cytochrome-c oxidase subunit 1 fragments of prey from these pellets. We used the Barcode of Life Database to identify prey, and evaluated the size of prey species based on published values. The mean wingspan of prey we recorded from our samples was smaller than average values reported for Rafinesque\u27s Big-Eared Bat using traditional methods (P ≤ 0.01), suggesting that surveys of culled insect parts beneath roosting sites may lead to biased estimates of the size and breadth of prey species eaten by gleaning bats. Mean wingspan of lepidopteran prey consumed by Rafinesque\u27s Big-Eared Bat in our study was larger (P ≤ 0.01) than values reported for the Myotis septentrionalis (Northern Long-Eared Bat ), which is a smaller, sympatric gleaner in eastern North America. Further, comparisons of our diet data with abundance of prey suggest macrolepidopteran taxa are consistently consumed by Rafinesque\u27s Big-Eared Bat to greater degree than microlepidotera. Our findings suggest that North American Corynorhinus consume a wider range of sizes and species of Lepidoptera than previously reported in studies based solely on identification of culled prey-wings beneath feeding roosts

Using LiDAR to Link Forest Canopy Structure with Bat Activity and Insect Occurrence: Preliminary Findings

Bats are an imperiled, yet ecologically-important group of vertebrate predators. Our ongoing research focuses on testing hypotheses about the relationships between the effects of fire on canopy structure and insect prey availability, and how these factors relate to use of foraging space by bats during the pre- and post-hibernation periods at Mammoth Cave National Park (MCNP). LiDAR-derived data (October 2010) were intersected with spatially explicit sampling of bat and insect populations (2010-2011) in order to characterize relationships between canopy structure, insect abundance, and bat activity. A canonical correspondence analysis for bat data suggested that forest canopy structure has a strong relationship with bat activity, particularly for species that echolocate at higher frequencies. Less variation was accounted for in a canonical correspondence analysis of insect occurrence. Even so, this analysis still demonstrated that variation in forest canopy structure influences the insect community at MCNP, albeit in varied ways for specific orders of insects