Emeritus and Distinguished Alumni Profile: Gary Fellers

Release Date:

The late Gary Fellers was a leader in amphibian and reptile conservation research who helped bring to light the worldwide decline of amphibians.

A bald man with a white beard and a jacket over a t-shirt with an animal on it

The late USGS herpetologist Dr. Gary Fellers

(Credit: Patrick Kleeman, USGS. Public domain.)

Note: This story is the first in a series of WERC Emeritus and Distinguished Alumni Profiles, highlighting the careers and accomplishments of emeritus scientists whose careers have been based at WERC. Their stories illustrate how USGS ecosystem science has influenced land and wildlife management in the West and beyond.

Dr. Gary Fellers, USGS WERC Researcher Emeritus, passed away in November 2019 after a forty-year career as an ecologist with USGS and the National Park Service. Over his long career, Fellers made many major discoveries in herpetology, the study of amphibians and reptiles. He was one of the earliest scientists to highlight worldwide declines of amphibians and worked toward better understanding the causes of those declines. He also closely monitored populations of the endangered Sierra Nevada yellow-legged frog within Yosemite National Park and contributed to a wider understanding of the Channel Islands National Park’s most secretive lizard.

Dr. Fellers’s expertise in herpetology began at a young age. Fellers grew up exploring the hills of Livermore, California. He brought home tarantulas, snakes, scorpions, and toads, and he helped a local high school teacher study tiger salamanders while he was still in grade school. At the age of 22, he was invited along on a weeklong trip to search for salamanders by Dr. David Wake, a renowned herpetologist and then-director of the Museum of Vertebrate Zoology at UC Berkeley. The trip was primarily made up of graduate students, but Fellers, an undergraduate student, was asked to serve as the local expert.


Secrets of the Island Night Lizard

Fellers left California for graduate school at the University of Michigan and the University of Maryland but returned to his home state in the late 1970s. Upon returning to California, Fellers worked as an instructor at California State University-Sacramento and soon in his first federal job at the Bureau of Land Management. In 1979, the National Park Service (NPS) called Fellers out of the blue and offered him a position as Assistant Regional Chief Scientist working out of San Francisco. They needed someone to work on island night lizards, which had been listed as “threatened” under the Endangered Species Act a few years earlier. Resource managers believed that habitat loss from farming, fires, livestock grazing, and the spread of invasive plants on the lizard’s native Channel Islands had caused a drop in numbers. Fellers took the job, setting off what became a decades-long research program. By 1983, Fellers was a Research Scientist with NPS based at Point Reyes National Seashore, regularly visiting the Channel Islands to study the island night lizard.

Fellers had noticed a gap in the research leading to the island night lizard’s listing under the Endangered Species Act. While other scientists had studied island night lizard taxonomy, distribution, and physiology, there were few studies on its ecology. In 1981, along with his technician Charles Drost, who would go on to become a research zoologist with the USGS Southwest Biological Science Center and longtime collaborator, Fellers launched a three-year research project to study island night lizard ecology on Santa Barbara Island, of the Channel Islands. They began by setting up pitfall traps — small containers buried with the lid at ground level and concealed with a small piece of plywood. The researchers got a surprise result early on: the so-called night lizards didn’t particularly like the nighttime. They turned up in the pitfall traps during the middle of the day but not in the early morning, indicating that the lizards foraged during the day and rested at night.

Two men sit in a grassy field during fieldwork

Herpetologists Gary Fellers and Charles Drost in the field.

(Credit: Patrick Kleeman, USGS. Public domain.)

More surprises were to come. Fellers and Drost tracked the captured lizards by dusting them with fluorescent dye or implanting radioactive tags beneath their skin. After years of alternating three-week-long stays on the island, sleeping in walled military tents and relying on propane heating for warmth, the scientists had their results. Island night lizards traveled only an average distance of three meters per day and had particularly small home ranges for reptiles. They also had diverse, robust diets, and lived extraordinarily long lives — up to 30 years, in some cases. Fellers and Drost estimated a population size of about 17,600 across Santa Barbara Island, instead of the estimated 550 - 700 that in part led to the species’ “threatened” listing.

Fellers and Drost published their results in 1991, based on data from the original three-year lizard study and additional data gathered in subsequent years while working on other Channel Islands projects. In the years that followed, Fellers and Drost, with other collaborators along the way, published five more articles on the island night lizard.  The most recent were published in 2018, nearly 40 years after their lizard work began. The island night lizard research program has had real impacts on the way that resource managers and the scientific community views the species, and in 2014, 13 years after the publication of Fellers and Drost’s first island night lizard paper, the U.S. Fish and Wildlife Service delisted the species. The final ruling cited three of Fellers and Drost’s publications.


The Case of the Disappearing Frogs

In 1993, Fellers joined USGS as a Research Biologist in its newly created Biological Resources Division (now the Ecosystems Mission Area), continuing to work based at Point Reyes National Seashore. Some of his most exciting work, though, would end up located far from the seashore. Fellers turned much of his attention to a major conservation issue that was then just emerging: the worldwide decline of amphibians, especially frogs. In 1991, Fellers had become the chairman of the California/Nevada working group of the Declining Amphibian Population Task Force. By 1994, Fellers had begun to document declines of frog species in the Cascades and Sierra Nevada. Five years after the release of their island night lizard paper, Fellers and Drost published another seminal article. The paper, “Collapse of a Regional Frog Fauna in the Yosemite Area of the California Sierra Nevada, USA,” provided evidence of widespread amphibian decline across the Sierra Nevada.

Photo of Dr. Gary Fellers

Dr. Gary Fellers, at home in the field.

(Public domain.)

Although the scientific community widely accepts the global decline in frogs and toads today, this was not the case in the 1990s. Many scientists remained skeptical that the decline was pervasive and widespread, and some argued that the declines were part of a natural “boom and bust” cycle. To provide insight into the question, Fellers and Drost repeated an intensive experiment from the early 1900s. Two zoologists, Joseph Grinnell and Tracy Storer, had surveyed a large stretch of the Sierra Nevada mountains for amphibian populations. Almost 80 years later, Fellers and Drost revisited the same ponds, streams, and meadows in the study, traveling from the edge of California’s Central Valley all the way to the western edge of the Great Basin. Most populations of frog and toad species had dwindled since Grinnell and Storer’s 1915-1919 surveys. Some had disappeared entirely.

“I think our study was one of the first that really convinced skeptics that there was widespread decline affecting large numbers of species, and it couldn’t be accounted for by year-to-year variation,” says Drost.

In the mid-late 1990s, attention to amphibian declines grew, eventually leading to the formation of the USGS Amphibian Research and Monitoring Initiative (ARMI) in 2000. Fellers was one of the founding biologists and continued to be a leading researcher for the program in the years since, examining frog declines in a variety of species and regions.

He studied the red-legged frog widely in California, surveying both at his Point Reyes home base and in the Sierra Nevada. The red-legged frog was federally listed as threatened in 1996; its recovery plan, published in 2002, drew extensively on Fellers’ work.

Fellers wasn’t just interested in documenting declines—he wanted to fully understand the causes. His research pointed to habitat loss, chytrid fungus disease, and pesticides as possible culprits. Fellers was surprised to find that the effects of pesticides were so widespread—he didn’t expect to be studying pesticides at all. In a 2018 interview, Fellers recalled one instance in which he watched a frog affected by pesticides hop in a circle as it attempted to catch an insect. In the future, he said, he’d like to see herpetologists pinpoint the main cause behind amphibian declines, whether that’s a single factor in the environment or a combination of threats.

But the frog research wasn’t all gloom: Fellers was one of several scientists who documented a long-term and widespread recovery of endangered Sierra Nevada yellow-legged frogs within Yosemite National Park. The study, published in 2016, offered hope that a combination of careful management efforts and the frogs’ natural resilience could help reverse declines in their populations.


“When Else But Now?”

Though Fellers is best known for his lizard and amphibian work, he explored the flora and fauna of California widely, especially in the Channel Islands and at Point Reyes. At Point Reyes, Fellers tracked the response of mountain beaver to a 1995 wildfire and spearheaded an effort to study the ecology of Townsend’s big-eared bats. Deer and deer mice, rare plants and ants—Fellers observed, tagged, analyzed, and wrote about them all. Collaborator and USGS scientist Patrick Kleeman has described Fellers as an “old-school naturalist,” who had a broad knowledge base that stood out in a research world where narrowly-focused research programs are common.

As a federal government scientist, Fellers valued how his position allowed him to apply his wide knowledge and fascination with the natural world to meaningful management issues. Fellers retired from USGS in 2013, but continued to serve as Researcher Emeritus, and the research he began continues on.

Scientist Gary Fellers receiving a Meritorious Service Award from USGS.

The late scientist Gary Fellers receiving a Meritorious Service Award from USGS.

(Credit: Mike Diggles, U.S. Geological Survey. Public domain.)

Sarah Allen, former Science Division Chief at Point Reyes National Seashore, said in 2013 that Fellers’ publications “are a window into the most pressing resource management issues of the past three decades.”

Fellers’ work was been shaped by his adventurous spirit of inquiry. In a 2018 interview, he recalled a family road trip when he spotted a porcupine walking near the side of the road. He got out and convinced his wife to distract it while he petted it. When else was he going to have this opportunity? It’s a moment that seems to capture Fellers’ attitude toward studying wildlife and trying new things—when else but now? And when “now” lasts 40 years, one can accomplish an awful lot.


Xochitl Rojas-Rocha contributed to the research and writing of this article.