With only 500 remaining, biologist joins fight to save Wyoming toad

FIU biology student Luke Linhoff is on a mission to save the endangered Wyoming toad.

The toad is no longer found naturally in the wild, and only about 500 remain in captivity in Wyoming, the only state in which they are known to reside. Its decline is the result of habitat loss, climate change and the amphibian disease Batrachochytrium dendrobatidis. Linhoff is studying their behavior, habitat and the location patterns of those that are released into the wild. His work and federal efforts to restore the Wyoming toad population were recently profiled by National Geographic.

The endangered Wyoming toad can grow up to 2.2 inches in length. The tracking device used measures the length of a U.S. quarter dollar. The device and harness used to track the toad weighs no more than 0.8 grams. Photo by Luke Linhoff.

Using a small tracking device no longer than a U.S. quarter that is held on by a backpack-inspired harness, Linhoff has outfitted and tracked more than 50 toads in the past two years. Although the data are still preliminary, he has found toads that are eased back into the wild in an outdoor pen or enclosure fare better in the short-term following their release than those released directly into the wild. The soft-released toads stayed closer to the moist, swampy areas of the wildlife refuge and used burrows to avoid predators. The others had a tendency to suddenly move large distances into dry areas away from the refuge where chances for survival are slim.

“There are many positive signs that the future for the toad is good, however there are many challenges,” said Linhoff, a doctoral student in FIU’s Herpetology Lab. “Many of the suspected initial causes of the toad’s decline haven’t been eliminated. Reintroductions for any animal often take years to be successful, but I am positive that the gains made in the program will greatly accelerate the Wyoming toad’s recovery.”

Traditionally, amphibian translocation programs have used the hard release strategy, offering no further support once the animal returns to the wild. Soft release approaches have fared successful for other animals, including tortoises, snakes and owls. However, little is known about adult amphibian reintroductions to their natural habitats because studies are scarce. Linhoff hopes his research provides guidance to other amphibian conservation programs on what strategies work.

Wyoming toads play an important ecological role, supporting the food web. Of particular interest to people, they feed on pests including ants, mosquitoes and beetles. According to Linhoff, removing the amphibian from an ecosystem can have significant, long-term impacts that may go undetected for years.

“The Wyoming toad is a unique species. I think they are valuable and significant in their own right,” Linhoff said. “Their extinction in the wild was likely caused by a combination of human activities and disease. It would be unethical to not try to save them.”

Linhoff is also studying the infection rates of Batrachochytrium dendrobatidis on tracked toads. He has presented his research on release methods to the American Society of Ichthyologists and Herpetologists and the Society for Conservation Biology.

FIU biology student Luke Linhoff tracks endangered Wyoming toads in the Mortenson Lake National Wildlife Refuge.