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

The devil is in the detail: Environmental variables frequently used for habitat suitability modeling lack information for forest-dwelling bats in Germany

In response to the pressing challenges of the ongoing biodiversity crisis, the protection of endangered species and their habitats, as well as the monitoring of invasive species are crucial. Habitat suitability modeling (HSM) is often treated as the silver bullet to address these challenges, commonly relying on generic variables sourced from widely available datasets. However, for species with high habitat requirements, or for modeling the suitability of habitats within the geographic range of a species, variables at a coarse level of detail may fall short. Consequently, there is potential value in considering the incorporation of more targeted data, which may extend beyond readily available land cover and climate datasets. In this study, we investigate the impact of incorporating targeted land cover variables (specifically tree species composition) and vertical structure information (derived from LiDAR data) on HSM outcomes for three forest specialist bat species (Barbastella barbastellus, Myotis bechsteinii, and Plecotus auritus) in Rhineland-Palatinate, Germany, compared to commonly utilized environmental variables, such as generic land-cover classifications (e.g., Corine Land Cover) and climate variables (e.g., Bioclim). The integration of targeted variables enhanced the performance of habitat suitability models for all three bat species. Furthermore, our results showed a high difference in the distribution maps that resulted from using different levels of detail in environmental variables. This underscores the importance of making the effort to generate the appropriate variables, rather than simply relying on commonly used ones, and the necessity of exercising caution when using habitat models as a tool to inform conservation strategies and spatial planning efforts.

Citizen Science Helps Uncover the Secrets to a Bat-Friendly Swimming Pool in an Urban Environment

For urban environments to support bat communities, resources need to be readily available. For example, bats typically use urban water sources such as drainage ditches and ponds; however, these sources can be ephemeral. During these periods, bats have utilized residential swimming pools, although they only appear to drink at pools when access to more natural equivalents are limited. This posed the question “can we make residential swimming pools friendlier for a diversity of bat species?” Using citizen science to determine which pool characteristics influenced bat activity, we distributed a questionnaire to residents in a suburban neighborhood in Fort Worth, TX, United States. It focused on observations of bat activity and the features of the pools and immediate surroundings. We distributed the questionnaire through social media, local presentations, and by mail throughout 2019 and 2020. We then used classification trees to determine which characteristics in combination influenced bat activity at the pools. We generated three different trees for bats observed (1) flying around the property and backyard, (2) above the swimming pool, and (3) drinking at the pool. We found that more bats were observed at unlit pools without bush or shrub borders. Furthermore, among pools with borders, activity was lowest at pools with textured interiors and ≥6 trees visible. The presence of features, such as fountains, then contributed to a reduction in bat observations in backyards and the presence of pets appeared to further reduce activity specifically over the pools. Where bats were observed drinking, this activity was reported the least at pools with bush or shrub borders, textured interiors, and trees <5 m and >10 m from the edge of the pools. Our study revealed that certain characteristics of residential swimming pools encouraged bat activity, while others discouraged them. Thus, it may be possible to make swimming pools more bat-friendly. For example, turning lights off in the evening when backyards are not in use and reducing clutter around pools could have an immediate positive impact on local bat populations. The implementation of such recommendations could improve urban habitats for bats overall and alleviate some of the negative implications of continued urbanization.

Occurrence of a forest-dwelling bat, northern myotis (Myotis septentrionalis), within Canada’s largest conurbation

While some species thrive in urban areas, many are absent from such environments. Those that are successful often have high behavioural flexibility that allows them to exploit new niches in a human-modified landscape. Northern myotis (Myotis septentrionalis) is an endangered bat species rarely identified in urban areas, though it is unclear whether this is due to absence or difficulties in surveying. We investigated the ecology of a population of northern myotis within Canada’s largest conurbation, including reproductive status, roosting preference, and movements. Using capture surveys, we confirmed the presence of reproductive females and healthy juveniles over two seasons. Using radio telemetry and acoustic surveys, we identified a cluster of tree roosts in the centre of the forest, and foraging areas concentrated around waterways within the bounds of the forest. These observations suggest the roosting and movement ecology of this population is similar to that observed for this species in rural environments, despite the urban surroundings. Our results suggest that northern myotis is not a synurbic species but can occur within urbanized environments when suitable habitat is available. We suggest that large forest patches with mature, interior forest cover are likely to be an important resource for northern myotis, and they will be vulnerable to the loss or fragmentation of these features in rapidly urbanizing landscapes. These findings are highly relevant to the ecology and preservation of northern myotis and present a case for greater consideration of this species in urban forests.