New Project: Species from Feces: A New Tool to Identify Bats in Culverts and on Bridges

Three bat species in Minnesota have been decimated due to white-nose syndrome. The northern long-eared bat is listed as endangered by the U.S. Fish and Wildlife Service, the tricolored bat listing is imminent, and the little brown bat listing is under consideration.

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Protecting endangered species requires protecting their habitat and reducing other stressors causing their decline. Bats may roost in the cracks and crevices of bridges and culverts but may not be visible during routine visual inspections. Regulations require assuming that endangered bats are present when evidence of bat use exists on a structure (e.g., feces, or guano), which complicates regulatory compliance and increases costs of construction and maintenance activities.

MnDOT wants to determine if bats are using structures requiring maintenance, regardless of whether bats are visible or even present during an inspection. If bats are using a structure, their guano is typically present. Bat guano contains DNA that can identify species, which can help MnDOT avoid lengthy regulatory review processes and costly mitigation strategies.

“This research will help streamline Endangered Species Act project reviews and avoid costly avoidance requirements such as seasonal work restrictions,” said Christopher Smith, protected species program coordinator, MnDOT Office of Environmental Stewardship. “Results will also help us understand where endangered bat species continue to occur in Minnesota, allowing for more targeted conservation and recovery efforts. Protecting our endangered bats is not only a legal requirement, but also a good idea as these bats provide important ecosystem services such as insect control.”

Objectives

In a new project, researchers will develop protocols and guidance for identifying bat species by sampling guano on culverts and bridges. Species identification will reduce excess regulatory burden on Minnesota transportation agencies and streamline environmental review processes for construction or maintenance activities.

The objectives are:

Collect guano samples from bridges with active bat populations and monitor locations with acoustic detectors
Perform DNA analyses to identify bat species
Calculate detection probabilities and develop a model for predicting the presence of endangered bat species
Develop guidelines for sample collection and probability estimations for identifying bats on bridges