Exploring Regional Variation in Roost Selection by Bats: Evidence from a Meta-Analysis

Abstract

Background and AimsTree diameter, tree height and canopy closure have been described by previous meta-analyses as being important characteristics in roost selection by cavity-roosting bats. However, size and direction of effects for these characteristics varied greatly among studies, also referred to as heterogeneity. Potential sources of heterogeneity have not been investigated in previous meta-analyses, which are explored by correlating additional covariates (moderator variables). We tested whether effect sizes from 34 studies were consistent enough to reject the null hypothesis that trees selected by bats did not significantly differ in their characteristics from randomly selected trees. We also examined whether heterogeneity in tree diameter effect sizes was correlated to moderator variables such as sex, bat species, habitat type, elevation and mean summer temperature.MethodsWe used Hedges’ g standardized mean difference as the effect size for the most common characteristics that were encountered in the literature. We estimated heterogeneity indices, potential publication bias, and spatial autocorrelation of our meta-data. We relied upon meta-regression and multi-model inference approaches to evaluate the effects of moderator variables on heterogeneity in tree diameter effect sizes.ResultsTree diameter, tree height, snag density, elevation, and canopy closure were significant characteristics of roost selection by cavity-roosting bats. Size and direction of effects varied greatly among studies with respect to distance to water, tree density, slope, and bark remaining on trunks. Inclusion of mean summer temperature and sex in meta-regressions further explained heterogeneity in tree diameter effect sizes.ConclusionsRegional differences in roost selection for tree diameter were related to mean summer temperature. Large diameter trees play a central role in roost selection by bats, especially in colder regions, where they are likely to provide a warm and stable microclimate for reproductive females. Records of summer temperature fluctuations inside and outside tree cavities that are used by bats should be included in future research.

Summer day-roost selection by eastern red bats varies between areas with different land-use histories

“…Meta-analyses and reviews of day-roost selection consistently find that tree diameter is a primary predictor of whether a tree is used by bats [29,41]. Larger diameter trees are thought to benefit bark and cavity roosting species because these trees provide more room for roosting groups of bats [16,22].…”

“…The underlying motivation for many studies of bat habitat selection is to guide management practices. Over the last several decades, a large body of work has emerged describing the habitat of different species in different regions, with some clear trends emerging [2,29,41]. Unfortunately, many of these trends are aggregated across species and are biased towards studies of cavity-and bark-roosting species.…”

Ground-based and LiDAR-derived measurements reveal scale-dependent selection of roost characteristics by the rare tree-dwelling bat Barbastella barbastellus

“…To investigate whether barbastelles selected roosts with particular characteristics, 16 habitat features that were considered to be biologically relevant for tree-roosting bats in the literature (Lacki and Baker, 2003;Kalcounis-Ruppell et al, 2005;Fabianek et al, 2015a;Naďo and Kaňuch, 2015) were measured on the ground or in QGIS (Quantum GIS Development Team 2015, version 2.8.1 Wien) and compared with those recorded from randomly selected trees at the plot, tree and cavity scale (Table 1). Random trees were selected by identifying the nearest potential roost tree to randomly selected point locations within home wood areas.…”

“…Meta-analyses have identified a number of habitat features that are typically important to treedwelling bats, including tree height and diameter, canopy closure, tree trunk girth and the occurrence of standing deadwood (Lacki and Baker, 2003;Kalcounis-Ruppell et al, 2005;Fabianek et al, 2015a;Naďo and Kaňuch, 2015). The frequency, type and size of cavities has also been shown to influence roost selection (Russo et al, 2004;Lučan et al, 2009).…”

Roosting ecology of the southernmost bats, Myotis chiloensis and Histiotus magellanicus, in southern Tierra del Fuego, Chile

“…The relationships between bats and these habitats are complex, with species using forested areas nonrandomly based upon their unique morphologies, behaviors, and physiologies (Fenton & Bogdanowicz 2002;Fabianek et al 2015, Vasko et al 2020) and the structure and composition of the vegetative community (Hayes 2007;Law et al 2016). For example, several species roosting in cavities or under bark select the tallest and largest diameter trees available, and in many cases prefer dead trees in specific stages of decay (Baker & Lacki 2006;Arnett & Hayes 2009;Fabianek et al 2015). This knowledge has proven useful to biologists and land stewards working in forests managed for timber production or wildlife habitat, but there is not much known about the roosting ecology of many bat species.…”