Relationships between bat occupancy and habitat and landscape structure along a savanna, woodland, forest gradient in the Missouri Ozarks

Abstract

Many land-management agencies are restoring savannas and woodlands using prescribed fire and forest thinning, and information is needed on how wildlife species respond to these management activities. Our objectives were to evaluate support for relationships of bat site occupancy with vegetation structure and management and landscape composition and structure across a gradient of savanna to forest in the Missouri Ozark Highlands, USA. We selected study sites that were actively managed for savanna and woodland conditions and control areas on similar landforms that had succeeded to closed-canopy forest. We used Anabat detectors to survey bats during the summers of 2010, 2011, and 2012. We fit single-species site-occupancy models to estimate detection probability and site occupancy. We evaluated a priori hypotheses in an information theoretic approach by evaluating support for candidate models that included habitat, landscape, and management effects. Site occupancy of evening bats (Nycticeius humeralis) was negatively related to poletimber and sawtimber density and positively related to fire frequency, while northern long-eared bat (Myotis septentrionalis) site occupancy was positively related to poletimber density and negatively related to understory stem densities. Site occupancy of big brown bats (Eptesicus fuscus), eastern red bats (Lasiurus borealis), and tri-colored bats (Perimyotis subflavus) were mostly not related to local vegetation structure and site occupancy was high across the savanna, woodland, forest gradient. We found more consistent and larger effect sizes for landscape-scale than for habitat-scale relationships; therefore, land managers should be cognizant of large-scale patterns in land cover when making local management decisions for these species. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.KEY WORDS big brown bat, eastern red bat, evening bat, northern long-eared bat, restoration, site occupancy, tricolored bat.

Habitat associations of bats in a working rangeland landscape

“…However, our results for L. noctivagans and E. fuscus tree cover responses differ from previous reports from forested regions (Ethier & Fahrig, 2011;Starbuck et al, 2015). In our study, L. noctivagans activity was higher at sites with higher tree cover and E. fuscus activity was lower in areas of higher tree cover.…”

“…Trees also provide foraging opportunities (Prevedello et al, 2017) and shelter from weather and predators (Verboom & Spoelstra, 1999). For L. cinereus and L. borealis, the positive responses to landscape-level tree cover we found in this study have also been reported in forests (Amelon, 2007;Ethier & Fahrig, 2011;Starbuck, Amelon, & Thompson, 2015).…”

“…The fourth species, E. fuscus, responded negatively to landscape-level tree cover but responded positively to tree proximity. For L. cinereus and L. borealis, the positive responses to landscape-level tree cover we found in this study have also been reported in forests (Amelon, 2007;Ethier & Fahrig, 2011;Starbuck, Amelon, & Thompson, 2015). L. cinereus and L. borealis are migratory and roost in foliage year-round, and L. noctivagans and E. fuscus often roost in cavities and beneath sloughing bark (Harvey et al, 2011).…”

“…In our study, L. noctivagans activity was higher at sites with higher tree cover and E. fuscus activity was lower in areas of higher tree cover. For further description of these models, see Table 1 ( Ethier & Fahrig, 2011;Starbuck et al, 2015). Conversely, neutral and positive responses to landscape-level tree cover have been documented for E. fuscus in forests F I G U R E 2 Variable coefficients for the competitive models for the activity levels of Lasionycteris noctivagans, Lasiurus cinereus, Eptesicus fuscus, and Lasiurus borealis on and near the Sheyenne National Grasslands during the summer of 2016.…”

A Review on the Dynamics of Prescribed Fire, Tree Mortality, and Injury in Managing Oak Natural Communities to Minimize Economic Loss in North America

“…Lack of early successional habitat in the eastern US, which savannas and open woodlands provide, is a major concern in wildlife conservation [49][50][51]. Savannas and woodlands support some of the highest levels of plant diversity [52][53][54], which begets a greater abundance of varied resources and habitats needed to conserve threatened and endangered wildlife species [55][56][57][58]. Both the dominance of oak tree crowns in the canopy and oak litter on the forest floor increase ecosystem productivity by supporting a greater diversity and abundance of invertebrates involved in energy and nutrient cycles than those communities without oak [59][60][61][62].…”