It was not what Jef Jaeger expected to find.
Four months prior, the associate professor-in-residence in the School of Life Sciences had released tiny relict leopard frog tadpoles in a pond at the Springs Preserve. When Jaeger returned in the fall for a population count, he discovered the frogs had not just survived but thrived far beyond his projections.
“They were humongous,” he said. “We didn’t realize that they could grow that fast in the wild.”
Jaeger soon spotted the secret to the frog’s success: Africanized bees shared the same watering hole. “These little frogs, which are basically the size of a bee, were grabbing up these bees and eating them,” he said. “It was pretty cool to see.”
The odds that the relict leopard frog could survive at all were once extremely long. The species was thought to be extinct along the Virginia and Colorado rivers. But scientists rediscovered it in Lake Mead in 1991, and in 2001 a multiagency conservation team coordinated by UNLV coalesced around the frog’s cause. In the 18 years since, the team has spared the frogs from the federal endangered species list, bolstered its population, and kept management of the frogs in local hands.
“When we started, there were only about 1,100 adult frogs on the face of the earth,” Jaeger said. “We now have somewhere around 3,000 adult frogs on the landscape.”
The team has raised more than 20,000 tadpoles and juvenile frogs, which are released in batches about 20 times a year at 14 sites around southern Nevada and northern Arizona.
“It’s hard to find good translocation sites for these frogs,” Jaeger explains. “The sites where they existed historically are covered in lakes, modified substantially, or infested with crayfish, exotic fishes or the chytrid fungus, which is causing massive declines in amphibians worldwide. Where we do find new sites, they are generally small and isolated, which makes them susceptible to flash floods, temporary loss of water and trespassing cattle. These small populations are quite vulnerable.”
They have powerful agencies pulling for them. Jaeger coordinates the efforts of the conservation team, which includes the National Park Service, U.S. Bureau of Land Management, Southern Nevada Water Authority, U.S. Fish and Wildlife Service, Nevada Department of Wildlife and the Arizona Game & Fish Department.
That teamwork resulted in the frog remaining off the endangered species list when the U.S. Fish and Wildlife Service re-evaluated its status in 2016.
“They recognized that there is already in place a successful strategy,” Jaeger said. “The trajectory of the species has been positive over the past decade. By not being on the list, it has allowed us to maintain local control and avoid massive amounts of paperwork and red tape. We can be more flexible in our approach.”
A steady stream of undergraduate biology students, in both volunteer and paid positions, aid the agencies in that approach.
Rebeca Rivera joined the project in her junior year, nine years ago. Since then she has been serving as Jaeger’s research assistant. Together with graduate student Anthony Waddle, they’ve been working on new research on the devastating chytrid fungus. They’ve already published two papers with a third in the works.
“I’m learning all the time,” Rivera said. “Just by going out to the translocation sites, you can see how much the habitat has changed over the years. It’s amazing to watch them grow and transform from a little embryo to a tadpole and then gain their four limbs.To see them four months after we release them as these huge frogs, almost tripled in size, is a beautiful glimpse of life.”