Tree Selection and Landscape Analysis of Eastern Red Bat Day Roosts

Abstract

Declining bat populations and increasing demands on forest resources have prompted researchers to investigate tree roost selection of forest bats. Few studies, however, have investigated different spatial scales and landscape pattern as criteria for selection of tree roosts. In 1999 and 2000, we radiotracked 23 eastern red bats (Lasiurus borealis) to 64 day roosts. Using univariate and multivariate comparisons, we tested roost tree variables with random tree data at 3 circular spatial scales: roost tree, plot, and landscape. We found 15 variables that were entered in a stepwise discriminant analysis to best differentiate between the roost and random samples; 11 (73.3%) were landscape variables measured with a geographic information system. On average (x̄ ± SE), red bats roosted in deciduous trees (42.0 ± 2.1 cm dbh) that were located in plots with more (3.1 ± 0.1 m2) basal area, higher (84.0 ± 1.3) percentage of canopy closure, and lower (27.2 ± 2.2) percentage of groundcover than random plots. At the landscape scale (by percent magnitude), red bat buffers (1,000‐m‐radius circle) had significantly less development (81.6%), less feeding operations (70.4%), more deciduous (52.9%) and pine forest (63.8%), and fewer local roads (5.4%) but more trails (94.1%), open water (61.4%), wetland areas (80.4%), and stream areas (63.1%) than random buffers. Red bat roost trees were significantly closer (χ2 = 22.0088, df = 1, P < 0.001) to trails (106.2 ± 13.3 m) than to streams (279.4 ± 28.5 m). Our results suggest that red bats in our study area select roosts in mature riparian forests near trails, open water, and wetlands. The high percentage of landscape values in the discriminant analysis lends support to using landscape metrics as an investigative technique of resource selection. We recommend that managers consider landscape factors when protecting red bat day‐roost habitat.

Insectivorous Bats and Silviculture: Balancing Timber Production and Bat Conservation

“…This approach has been recommended in published studies (Loeb and Waldrop 2008;; however, other sources report both stand and landscape metrics in North America and Europe to be important in selection of activity areas of bats (Loeb and O'Keefe 2006;Yates and Muzika 2006;FuentesMontemayor et al 2013), with tri-coloured bats, P. subflavus, and eastern red bats, L. borealis, most affected by local stand structure, northern long-eared bats, M. septentrionalis, negatively affected by forest edge, and Indiana bats, M. sodalis, positively affected by dead tree density and non-forested land cover. Other studies corroborate that selection of roosting sites in both bark-and cavity-roosting and foliage-roosting bat species is strongly influenced by landscape-scale metrics in both eastern and western forests of North America (Limpert et al 2007;Arnett and Hayes 2009;Lacki et al 2010). …”

Monitoring seasonal bat activity on a coastal barrier island in Maryland, USA

“…Bat species composition documented with continuous long-term acoustic monitoring at ASIS was similar to that on the lower Coastal Plain of the southeastern United States where the majority of activity throughout the year was comprised of lasiurine bats and myotine bats were absent (Menzel et al 2000(Menzel et al , 2003Limpert et al 2007;. On the Coastal Plain of the southeastern United States, including Maryland, myotine bats were documented less frequently than in the western Piedmont (Menzel et al 2000(Menzel et al , 2003.…”

Landscape Metrics and Indices: An Overview of Their Use in Landscape Research

“…Landscape metrics have been used to determine the landscape preferences of raccoons (Henner et al, 2004), gray wolves (Mladenoff et al, 1995), wild hogs (Gaines et al, 2005); moose (Maier et al, 2005), deer (Foster et al, 1997;Finder et al, 1999;Kie et al, 2002), black bears (Kindall and Van Manen, 2007), ocelots (Jackson et al, 2005), elk (Stubblefield et al, 2006), possums (Eyre and Buck, 2005) and bats (Limpert et al, 2007). Different species provide different correlations with landscape metrics depending on their landscape preferences, i.e., large compact patches are preferred by wild hogs (Gaines et al, 2005), moose (Maier et al, 2005), deer (Table 1; Foster et al, 1997;Plante et al, 2004) and possums (Eyre and Buck, 2005), while ocelots (Jackson et al, 2005) and gliders (Table 1; McAlpine and Eyre, 2002) preferred areas that had a greater degree of fragmentation (i.e., a larger number of patches of smaller size, and with more edge).…”