Jennifer M. Menzel

Effects of group selection silviculture in bottomland hardwoods on the spatial activity patterns of bats

Abstract The effects of forest management practices on the spatial activity patterns of bats are poorly understood. We determined the effect of group selection timber harvests on the spatial activity patterns of bats below the forest canopy at the Savannah River Site, Aiken, SC, using the Anabat system. We monitored the effect of group selection timber harvests on feeding and foraging activity of bats at three spatial scales: among habitats within a landscape, among harvested and unharvested areas in the stand where patches were harvested, and within an individual gap. Habitats examined included Carolina bays, unharvested bottomland hardwoods, bottomland hardwoods in which a group selection harvest occurred, and upland stands containing a hardwood/pine mix. Within the harvested stand, we compared the level of foraging and feeding activity among large patch cuts (gaps), small gaps, skidder trails, and forested areas. Within the large gaps, we compared activity among the center of the gap, the edge of the gap, and the forest surrounding the gap. Levels of bat activity differed among stands. More activity occurred in the bottomland stand in which patches had been harvested and around Carolina bays than in unharvested stands of bottomland hardwoods and upland hardwoods and pines. Levels of bat activity also differed among harvested and unharvested areas within the stand and among different positions within gaps and the surrounding forest. Activity was concentrated in forest gaps and along skidder trails. Within gaps, activity was concentrated along the edge between the gap and forest. Spatial activity patterns also depended on the species of bat. These results suggest that the inclusion of gaps in bottomland hardwoods increases the total level of foraging and feeding activity of bats below the canopy. They also suggest differences in the size and shape of the harvest affect the total amount of bat activity recorded in the gap and that these effects may be species specific.

Developing a habitat model for the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus) in the Allegheny Mountains of West Virginia

We examined occurrence patterns and habitat data for the Virginia northern flying squirrel (Glaucomys sabrinus fuscus) in the central Appalachian Mountains of West Virginia, USA with the intent to develop a habitat model. Topographic conditions (elevation, landform index, surface curvature, slope gradient and aspect) and proximity to coniferous cover were evaluated for three study areas where flying squirrel presence has been documented via nest box surveys. In our model, Virginia northern flying squirrel presence was associated with proximity to conifer cover (P<0.001), but not to any other habitat variables tested. We developed a logistic regression model and implemented that within a geographic information system to delineate potential habitat. Statistical relations were not sufficient to predict flying squirrel occurrence with a reasonable degree of confidence. Current nest box monitoring efforts provide needed year-to-year population trend information, however, they are not sufficient to delineate potential habitat using quantitative approaches. More detailed micro- and macro-habitat relationship studies of the Virginia northern flying squirrel will be necessary for successful management and eventual recovery of this endangered species.

Review of the forest habitat relationships of the Indiana bat (Myotis sodalis)

Reviews the available literature on the ecology of the endangered Indiana bat (Myotis sodalis), including its selection and use of hibernacula, roost trees, and foraging habitat. An extensive list of published references related to the Indiana bat is included.

FOOD HABITS OF SEVEN SPECIES OF BATS IN THE ALLEGHENY PLATEAU AND RIDGE AND VALLEY OF WEST VIRGINIA

Abstract We captured 159 bats in the Allegheny Plateau and Ridge and Valley physiographic provinces of West Virginia during summer 1998, including the northern long-eared myotis (Myotis septentrionalis; n = 40), little brown myotis (M. lucifugus; n = 34), big brown bat (Eptesicus fuscus; n = 29), eastern pipistrelle (Pipistrellus subflavus; n = 27), eastern red bat (Lasiurus borealis; n = 22), hoary bat (L. cinereus; n = 5), and silver-haired bat (Lasionycteris noctivagans; n = 2). We analyzed fecal pellets of each bat to determine food habits. Diets of northern long-eared myotis and eastern red bats were dominated by Coleoptera (42.3 and 24.5%, respectively) and Lepidoptera (31.1 and 47.0%, respectively). Diet of big brown bats primarily consisted of Coleoptera (67.5%). Diet of hoary bats was dominated by Lepidoptera (98%). Diet of silver-haired bats was moderately diverse, but primarily composed of Lepidoptera (47.5%) and Diptera (20.0%). Diets of little brown myotis and eastern pipistrelles were highly diverse, consuming an even proportion of six orders of insects including Coleoptera, Hemiptera, Lepidoptera, Homoptera, Diptera, Hymenoptera, and Tricoptera. Diets of these seven species of bats did not differ notably from diet of each species reported from other regions of the eastern United States. Our results provide information about food habits of bats that are common throughout the central Appalachian Mountains.

Nest tree use by the endangered Virginia northern flying squirrel in the central Appalachian Mountains

Abstract Little is known about nest tree use of the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus). Because nesting sites could be a limiting factor, it is important to understand the denning ecology to further manage and protect this subspecies. We compared characteristics of nest trees used by Virginia northern flying squirrels with randomly selected trees during summer and fall of 2000 and 2001. We tracked 13 Virginia northern flying squirrels to 59 nest trees. The squirrels used an average of 3.6 nest trees/month, switching trees frequently. Sixty-nine percent of the nests were in cavities and 31% were leaf nests. Yellow birch (Betula alleghaniensis) and Fraser magnolia (Magnolia fraseri) were selected for nest trees more than expected based on availability. A large portion of nest trees were in larger and taller trees than trees in the surrounding area. There also was a significant number of trees located next to or near skidder and hiking trails. Although a large number of nest trees were similar across sites, there was variation in the characteristics of nest trees used, suggesting that Virginia northern flying squirrels may not be as specialized in nest tree selection as indicated by previous studies.

Home Range and Habitat Use of Male Rafinesque's Big-eared Bats (Corynorhinus rafinesquii)

Abstract We examined home range size and habitat use of four reproductively active male Rafinesques big-eared bats (Corynorhinus rafinesquii) in an area of the Upper Coastal Plain of South Carolina during August and September 1999. Corynorhinus rafinesquii had biphasic activity patterns, with most foraging activity occurring during the first 4 h after sunset and 2 h before sunrise. Mean home range size calculated using the adaptive kernel method with a 95% use distribution was 93.1 ha. Although large contiguous tracts of mature bottomland hardwoods were common in the study area, most foraging activity occurred in young pine stands. Only 9% of foraging areas were in bottomland hardwoods.

The distribution of the bats of South Carolina

Abstract There is a paucity of information available about the distribution of bats in the southeastern United States. Golley (1966) recorded the distribution and gave a brief summary of the natural history of 11 of 14 species of bats that occur in South Carolina and DiSalvo et al. (2002) recently reported on the distribution of 13 species of bats that occur in South Carolina based on bats submitted to the public health personnel for rabies testing. Maps provided by Golley are outdated and those provided by DiSalvo et al. are not inclusive of museum records, capture records reported in the literature, or records from the South Carolina Department of Natural Resources (SCDNR). We synthesized records from museums, bat captures, and bats submitted for rabies testing to provide a more accurate and useful distribution for natural resource managers and those planning to research bats in South Carolina. Distributional information, including maps, collection localities within counties, and literature references, for all 14 species of bats that occur in South Carolina has never been synthesized. To provide better information on the states bat fauna, we have updated distributions for all species that occur in South Carolina.

Influence of Summer Temperature on Sex Ratios in Eastern Red Bats (Lasiurus borealis)

Abstract Using museum records, we examined sex ratios for 32 collections of eastern red bats (Lasiurus borealis) in the eastern United States. Results from logistic regression analyses indicate that female-dominated sex ratios are associated with warmer, mean high temperatures in June. Male-dominated collections, and those with approximately even sex ratios, occurred disproportionately in the Appalachian Highlands where monthly mean high temperatures were lower than in either the Central Lowlands-Interior Low Plateaus or Coastal Plain-Piedmont regions. Efforts to maximize conservation of summer roosting and foraging habitat that favors the female population segment of eastern red bats should be directed at areas where June mean high temperatures exceed 28.5 C.

Late winter home range and habitat use of the Virginia northern flying squirrel (Glaucomys sabrinus fuscus)

We radio-tracked two male and one female Virginia northern flying squirrels (Glaucomys sabrinus fuscus) in the Allegheny Mountains of West Virginia at Snowshoe Mountain Resort, in winter 2003 and Canaan Valley National Wildlife Refuge in winter 2004, respectively, to document winter home range and habitat use in or near ski areas. Male home range size in the winter was larger than that reported for males during summer and fall, whereas the female home range we observed was smaller than those reported for summer and fall. However, winter habitat use was similar to summer and fall habitat use reported in other studies. Virginia northern flying squirrels foraged and denned in both red spruce (Picea rubens)-dominated forests and northern hardwood forests; however, selection of red spruce-dominated forests and open areas was greater than expected based on availability. Use of northern hardwood forest occurred less than expected based on availability. Male squirrels denned near, and routinely crossed, downhill ski slopes and unimproved roads during foraging bouts, whereas the female approached, but did not cross forest edges onto roads or trails.

Mensural discrimination of Myotis (Chiroptera, Vespertilionidae) in the southeastern United States

Discriminant functions were constructed using external and cranial measurements to distinguish the six species of Myotis that occur in the southeastern United States. Twenty-three morphological characters were measured from 161 specimens of Myotis. Differences among species for morphological characters were examined using analysis of variance and discriminant analysis. A bootstrap procedure was used to validate the final discriminant model using all six species. Differences were observed among species for all 23 characters measured in univariate tests, but the range of values for most species overlapped the range of other species. Bootstrap analyses indicated that our discriminant functions constructed using both external and cranial measures allowed correct identification of 99.4% of specimens examined. Discriminant models constructed using only cranial characters permitted correct identification of 96.9% of specimens examined. Univariate analyses were not reliable because variation within species prevented unambiguous identification of any species based on a single character. However, Myotis species in the southeastern United States can be distinguished with a high level of accuracy using multivariate techniques when a sufficient number of measurements are used.