Bat Chat A Conversation with a noted expert
Shawn Thomas conducting mine survey work in San Diego
Shawn Thomas looking around mines
Shawn Thomas conducting mine survey work in San Diego
Photo: Rachel Harper

Going Underground

Protecting the habitat of subterranean bats across the U.S.
by Stefanie Waldek

hawn Thomas leads the Subterranean Team of Bat Conservation International’s (BCI) Habitat Protection and Restoration Program, which works to preserve, protect, and restore subterranean habitat through federal and state land management agencies and private landowner collaborations. He joined the Subterranean Team in 2014 after working with the National Park Service to manage, explore, and document the cave systems of the western U.S.

What threatens bats’ subterranean habitat?

Several bat species are considered “cave obligates,” which means they rely on caves or similar subterranean spaces to serve as habitat during important life cycle phases. Caves and abandoned mines comprise many bat roosts we work to protect, and these sites are highly susceptible to habitat disturbance and loss. Visitation and recreation in caves and abandoned mines, as well as nearby development, can cause unintended disturbances, and if it happens often enough, bats may abandon their roosts.

Bats also rely on healthy surface ecosystems to survive. While their subterranean roosts provide critical homes for raising their pups or undergoing hibernation, all bats must emerge from their caves to forage and drink. An intact ecosystem is necessary for providing a healthy abundance of insects, pollen, and clean water that subterranean bats require.

BCI’s subterranean team has recently partnered with the U.S. Fish and Wildlife Service—what projects are you working on with the agency?

We are excited about our new partnership with the U.S. Fish and Wildlife Service. This partnership represents an expansion of our work onto the National Wildlife Refuge system, which protects some of the finest wildlife habitat in the country. We are targeting several refuges, both small and large, that were identified by the presence of abandoned mines. By constructing bat gates over abandoned mine entrances, we are helping protect this important bat and wildlife habitat and ensuring public safety.

As part of this process, we’re also conducting cultural surveys that reveal the mining histories at these sites, which establishes protection for significant cultural resources. We are also looking for opportunities for habitat restoration in and around mine openings. We feel fortunate to contribute to the integrity of these iconic places, and with an agreement to conduct this work for the next five years, we are just getting started.

What are the differences between caves and abandoned mines in terms of your work?

From a survey and habitat protection point of view, we approach caves and abandoned mines equally, but from a human safety perspective, our approaches diverge slightly. We follow rigorous safety protocols for all sites, but abandoned mines present unique hazards that require additional protocols and personal protective equipment to ensure we are maintaining our high safety standards. Regardless of whether we are surveying caves or abandoned mines, we approach them with respect for the unique habitat they offer, and we feel fortunate to experience, if only briefly, these special subterranean realms.

I’ve always wondered whether bats are in tune with the differences between caves and abandoned mines or if they “see” them as the same. Both sites offer ideal habitat for subterranean bats, and a bat probably doesn’t give much thought about whether it prefers roosting near stalactites or ore chutes.