Detecting bat environmental DNA from water-filled road-ruts in upland forests

Declines in population and diversity of North American bats are rapidly occurring due to habitat loss, incidental take from various industry projects, and lethal White-nose Syndrome disease. Of the 14 species of bat occurring within the Appalachian Plateau of eastern United States, four are protected and managed under the Endangered Species Act (ESA). Therefore, it is critical to accurately census habitat for appropriate conservation measures, yet traditional sampling methodology, such as mist netting and acoustic recordings, can be time-intensive and biased. Instead, a passive sampling tool that does not rely on the a priori knowledge of bat roosts may provide crucial information on bat communities. Major advancements over the past decade through the analysis of environmental DNA (eDNA – genetic material released from urine, waste, mucus, or sloughed cells) have considerably improved surveys for a wide-range of aquatic taxa. In fact, methods for eDNA collection from aquatic environments have been developed for detection of terrestrial mammals, such as coyotes (Canis latrans), invasive wild boar (Sus scrofa), elusive jaguar (Panthera onca), and even entire terrestrial mammal communities.

In the water-limited habitats of forested uplands of the Appalachian Plateau, water-filled road-ruts are important resources for bats. Therefore, Stantec developed an environmental DNA (eDNA) protocol to sample isolated road-ruts that may have the presence of sloughed cellular material from actively drinking bats. As a bat flies by for a drink, it will likely shed hair and saliva cells into the puddle, which can then be collected and tested for DNA. The detection of bat eDNA was investigated from a positive control experiment, and across 47 water samples collected in Kentucky and Ohio. Stantec successfully detected eDNA from big brown bat (Eptesicus fuscus) and eastern red bat (Lasiurus borealis) from these sampled water-filled road-ruts. Additionally, eDNA detected several other amphibians (toads, frogs, and newts), birds (eastern phoebe and wood thrush), and mammals (opossum, deer, racoon, and black bear). These results suggest eDNA left behind in road-ruts provides an additional detection tool for surveying biodiversity across these upland forests. Additionally, positive detections for endangered bat species may be crucial for improving bat conservation efforts across these landscapes.

Read the paper at bioRxiv.