Habitat destruction and degradation are mostly to blame for the dwindling numbers of amphibians worldwide, but there are other factors contributing to the overall decline—and some of these remain elusive. With only a few surviving wild and human-facilitated populations, Rana sevosa, or the dusky gopher frog, is the second most endangered frog in the U.S., according to the National Wildlife Federation. Its existence is considered tenuous at best and some major barriers to its recovery are still poorly understood.
With five years of funding from U.S. Fish and Wildlife Service (USFWS), Western Carolina University’s Joseph Pechmann spearheads research collaborations to provide critical insight into the mysterious issues plaguing this frog. He ultimately hopes to prevent extinction and promote a robust rebound in the dusky gopher frog’s home states of Mississippi, Louisiana, and Alabama. Pechmann, an associate professor in the Department of Biology, has been studying amphibians for 37 years and started focusing on the dusky gopher frog in 2002 while teaching at the University of New Orleans. This was shortly after the frog was placed on the federal endangered species list in 2001.
The researchers are aware of one remaining natural population in Glen’s Pond in southern Mississippi. The Glen’s Pond population—along with the species—probably would have gone extinct in the mid-2000’s if not for the team’s supplemental rearing of tadpoles.
Pechmann and his colleagues found that gopher frogs breed in open canopy, ephemeral ponds containing herbaceous vegetation and few or no trees. Many of these ponds have been destroyed by urbanization and other land use changes, while others have been turned into permanent ponds unsuitable for this frog’s survival. Despite dedicated efforts and some successful interventions by the USFWS and collaborators, Pechmann says the relative importance of terrestrial habitat changes and aquatic habitat changes remains unknown.
“There are currently six populations that have been established by human intervention, meaning that we have observed some reproduction at these sites. Two of the six populations, however, are probably not self-sustaining, and it’s too early to tell if the other four will be self-sustaining,” said Pechmann.
In collaborative projects with the USFWS, University of Southern Mississippi (USM), USDA Forest Service, The Nature Conservancy of Mississippi, and the State of Mississippi, the researchers found that a protozoan parasite (Dermomycoides sp.) was responsible for many of the deaths in their breeding ponds. Not much is known about this disease-causing microorganism yet. For a deeper examination, Pechmann is working with Robin Overstreet and his team at the USM’s Gulf Coast Research Laboratory to study and monitor Dermomycoides sp.
The study, titled “Research on conservation and recovery of the endangered dusky gopher frog,” is funded with a $383,000 award through 2021 by the USFWS.