Life in a northern town: rural villages in the boreal forest are islands of habitat for an endangered bat

Abstract

Citation: Thomas, J. P., and T. S. Jung. 2019. Life in a northern town: rural villages in the boreal forest are islands of habitat for an endangered bat.Abstract. Urban development is detrimental to many wildlife species; however, endangered little brown bats (Myotis lucifugus) may be attracted to human settlements, making them a synurbic species. Buildings likely provide high-quality roosting habitat, which may be a limiting factor in the boreal forest where trees are typically small and potentially unsuitable for hosting large maternity colonies. In the boreal forest, there are relatively few urban developments in a matrix of wilderness and apparently suboptimal natural roosting habitat; thus, we hypothesized that isolated rural villages were islands of summer habitat for little brown bats that may be important for their conservation and recovery. To test this hypothesis, we investigated the relationship between little brown bat activity, foraging rates, and proximity to rural villages. We expected bat activity and foraging rates to increase with proximity to villages, as bats should optimally forage near their roosts to minimize flight costs. We used ultrasonic detectors to passively monitor bat activity near three rural villages in Yukon, Canada, and characterized bat habitat with forest measurements and remotely sensed data. Bat activity increased with proximity to village centers, but foraging activity did not, suggesting that human settlements in the boreal forest were important as roosting rather than foraging habitat. Bat activity was higher near water bodies and areas with relatively high densities of linear features (e.g., roads and transmission lines), perhaps because prey were most abundant near water features and along forest edges. The island phenomenon we observed (i.e., higher bat activity near villages) has also been documented in larger human settlements at lower latitudes, where urban areas provided better roosting habitat than surrounding agricultural matrices. Given that little brown bats were concentrated near rural villages, small human settlements should be a focus of conservation efforts in the boreal forest-particularly the identification and protection of buildings used as maternity colonies. Our study advances knowledge of little brown bat habitat requirements in the boreal forest and identifies habitats that may be important for their recovery.

Foraging habitat drives the distribution of an endangered bat in an urbanizing boreal landscape

“…The absence of data on natural roosts is a limitation; however, we expect that roosting trees are scarce in our study area, given the prevalence of young forest and regenerating burn, where suitable large‐diameter trees and snags may be scarce (Crampton and Barclay 1998, Jung 2020). Interestingly, bat activity levels in this study were substantially lower than in rural villages with much smaller human populations and urban footprints (Thomas and Jung 2019). This may be attributed to the broad distribution of potential roosts in the Whitehorse area; conversely, anthropogenic roosts are confined to a comparatively small area within rural villages, perhaps resulting in higher concentrations of bat activity.…”

“…Several acoustic studies in southern Yukon reported that little brown bats were the most common bat species by far, albeit at low densities (Slough and Jung 2008, Thomas et al 2019, Thomas and Jung 2019, Jung 2020). Other bat species are likely present but rarely detected (Jung et al 2006, Slough et al 2014).…”

“…Although urbanization is detrimental to many species of bats (Russo and Ancillotto 2014, Jung and Threlfall 2016), the endangered little brown bat ( Myotis lucifugus ) is a synurbic species often found at higher densities near human settlements (Coleman and Barclay 2012, Thomas and Jung 2019). Their synurbic tendencies are a consequence of their ability to exploit anthropogenic roosts (e.g., buildings, bridges), and in some high‐elevation or high‐latitude regions, they may depend on them (Johnson et al 2019, Thomas and Jung 2019). Buildings provide a thermoregulatory advantage for reproductive female bats (Lausen and Barclay 2006, Johnson et al 2019), particularly in the north where the climate is cool and natural roosting habitat is scarce (Slough and Jung 2008, Olson and Barclay 2013, Randall et al 2014).…”

Spatiotemporal Analysis of the Nonlinear Negative Relationship between Urbanization and Habitat Quality in Metropolitan Areas

“…The ecological conditions in 20% of YRDUA deteriorated, and the ecological conditions in 40% increased from 1995 to 2010 [19]. The improvement in habitat quality in urban areas has also been testified in accelerating vegetation growth [21,22,58] and enhancing species richness [18,20] in urban environments compared to those in rural equivalents.…”

“…However, the correlation trends are not completely consistent among different studies. The relationships between urbanization and the diversity of plants [16], amphibians [17] and mammals [18] have been separately analyzed, and it was found that there were no negative and even positive effects in urban-rural gradients. In addition, using non-field survey approaches, the positive influence of urbanization on environmental variation has been observed at the city, regional and national scales.…”