Ecological Significance, History and Range
In 2012, the IUCN (International Union for the Conservation of Nature) identified the Dusky Gopher Frog, Lithobates sevosus, as one of the top 100 most endangered species in the world. Commonly known as the Mississippi gopher frog, this endangered amphibian was historically found across parts of southwest Alabama, southern Mississippi and southeast Louisiana. Related species of the gopher frog occur more broadly across the Southeast.
Conservancy scientists and their colleagues from ther agencies and organizations are working to save this species by restoring and managing habitat, studying breeding habits, raising tadpoles in tanks to give them a 'head start' before releasing them into the wild, and creating new populations via translocation.
Formerly classified by the U.S. Fish and Wildlife Service as a subspecies of the gopher frog, the Dusky Gopher Frog has been elevated to full species status.
The species' current range is limited to only three ponds in south Mississippi: Glen's Pond, Mike's Pond and McCoy's Pond. The McCoy's Pond population is known only from a single call.
Found almost exclusively among the upland sandy habitats of the Southeast’s native longleaf pine ecosystem, the Dusky Gopher Frog spends most of its time in stump holes and burrows – often those made by the gopher tortoise, another imperiled species. Breeding adults and tadpoles thrive in shallow, fishless ephemeral and isolated wetlands embedded within the longleaf pine woodlands.
Unfortunately, the Dusky Gopher Frog population has declined significantly due in large part to loss of ephemeral wetlands and native longleaf pine habitat, the decline of gopher tortoises, invasive species, disease, drought conditions and lack of natural and prescribed fire.
Listed as endangered by the State of Mississippi in 1992 and by the U.S. Fish and Wildlife Service in 2001, biologists estimate the total Dusky Gopher Frog population to be less than 250 mature individuals.
The primary historic and current threat to the Dusky Gopher Frog is loss of habitat, specifically loss of fishless ephemeral wetlands and native longleaf pine forests. Development, urban sprawl and fire suppression have contributed to the decline of the longleaf pine forest, which once covered some 90 million acres in the South, from Virginia to Texas.
Today, less than 5 percent of old-growth longleaf pine forest remains, causing the Dusky Gopher Frog and other species like the gopher tortoise – which the frog relies on for underground burrows – to drastically decline. Prescribed fire is essential to maintaining open upland habitat important to both of these species, and to the health of open, grassy, relatively treeless ephemeral ponds essential to the breeding cycle of gopher frogs
The Dusky Gopher Frog...
- is a stubby frog with ridges on its back;
- is either uniformly dark or has irregular dorsal spots, while its throat and belly areas tend to be pigmented;
- has prominent warts on its back that secrete a bitter white substance used as a defense mechanism;
- emits a loud, guttural call that sounds like snoring;
- typically lives less than 7 years, achieving biological maturity around 6 to 8 months in males and 24 to 36 months in females;
- usually breed between January and March, but may breed in the fall, if conditions are right;
- young are herbivores and adults are invertivores (feeds on invertebrates).
What The Nature Conservancy Is Doing
A generous donation of 292 acres by M.C. Davis, a devoted conservationist, is helping biologists manage one of the last remaining wild populations of Dusky Gopher Frog.
The property, known as “Mike’s Pond,” was identified as having gopher frogs in 2004. The Conservancy is managing the site through prescribed fire and removal of cogongrass, an invasive plant which threatens native plant communities and animal species, like the gopher frog and gopher tortoise, that depend on them.
In 2004, biologists began transferring tadpoles and young frogs from Glen’s Pond on U.S. Forest Service property in Harrison County to an ephemeral pond on the Conservancy’s 1,700-acre Old Fort Bayou Preserve in Jackson County in an attempt to establish a new population.
This effort continues today. Biologist Josh Cook of the Gulf Coast Research Laboratory has since recorded a gopher frog calling at this site, and subsequently, one gopher frog egg mass was identified.
The Conservancy is also rehabilitating other potential gopher frog ponds for future translocation efforts and is assisting the Mississippi Department of Wildlife, Fisheries and Parks with gopher frog restoration efforts on state-owned lands.