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‘Got one!’: Agencies complete collaborative frog survey in Nevada
“Got one!” A voice calls out across a field of waist-high sedge. Nets dip and splash into the tiny, yet deceptively deep pond in search of elusive prey while feet make sucking sounds as they are pulled from knee-deep mud.
These are the sounds of Frog Week.
For the past 14 years, scientists and volunteers have descended on the remote, but picturesque Indian Valley in central Nevada’s on the Humboldt-Toiyabe National Forest. They make the long trek on unmarked dirt roads, past a long forgotten ghost town, to survey and tag Columbia spotted frogs.
Each year, public volunteers join biologists from federal and state agencies as well as from the Nevada Natural Heritage Program to spend four nights sleeping in tents, campers and cars just to experience Frog Week.
But it’s voluntary, collaborative efforts like these that helped recover the Columbia spotted frog population, removing it as a candidate from the federal endangered species list after 22 years.
Frog Week coordinator Teri Slatauski, a biologist with the Nevada Department of Wildlife, has been involved with the project since its first year. She said there’s never a shortage of volunteers. “We had nearly 40 participants during the course of the week and in some cases I even had to turn some folks away.”
Plus, Slatauski said, the group needs to have enough gear to outfit volunteers and crew leaders capable of training them how to properly survey, record data and tag frogs.
“Volunteer interest has grown so much over the past two years that we’ve even had to add a second outhouse for them all,” she said.
The Columbia spotted frog was first designated as a candidate species for listing under the Endangered Species Act in 1993.
However, collaborative conservation efforts by partner organizations across northern Nevada, southeastern Oregon and southwestern Idaho increased the species’ population successfully enough that the U.S. Fish and Wildlife Service removed it from the candidate list in 2015.
Tagging the frogs in Indian Valley during Frog Week began in 2004. Passive integrated transponder tagging, or “PIT” tagging, is the process of inserting a small device not much bigger than a grain of rice under the skin of the frog. Each tag contains a unique numeric code that is recorded by biologists along with identifying data such as its length and sex, and the location the frog was captured.
Chad Mellison, a U.S. Fish and Wildlife Service biologist who began tagging the Toiyabe population 14 years ago said the monitoring effort played a vital role in the species’ recovery.
“The tagging efforts have allowed us to better understand the frogs’ population size and survival rates, life history information and their movement patterns,” he said. “The data gathered in the Toiyabe population, as well as in five other long-term sites across the Great Basin, informed the Service’s decision not to list the Columbia spotted frog under the Endangered Species Act.”
Once a frog is captured, it’s measured, sexed and a handheld scanner is used to determine if a tag is already in place. If not, a biologist makes a small incision at the base of the frog’s neck with a pair of surgical scissors. The tag is then inserted and slid under the skin to the base of the spine, an antiseptic is applied to aid the healing process and the frog is released back into the pond.
The long-term tagging efforts have helped scientists learn more about the lifespan of Columbia spotted frogs. Once they become adults, male frogs have lower survival rates than females, possibly due to their smaller size making them more susceptible to predation. Scientists estimate that most males only live three to four years, while females typically survive five to eight years.
“However, one female we captured near Tennessee Gulch in northern Nevada in 2016 was first tagged in 2004,” Mellison said. “At 65mm when captured in 2004, that puts her estimated age (based on size) at three to four years old. When recaptured in 2016 she was a whopping 83mm in length and an estimated 17 years old! That makes her the oldest documented Columbia spotted frog.”
Volunteers like Nicole Zimmerman, an Oak Ridge Institute for Science and Education fellow interning with the U.S. Forest Service in Washington, D.C., jumped at the opportunity to leave the office and spend a week counting frogs.
“One of the big projects I’m working on for the Forest Service involves building a citizen science toolkit… so, I knew this opportunity would help me understand and do my job better here in D.C.,” she said.
“I was initially a little intimidated because I had never been frogging before but by the end of the week, I was kayaking around a pond with a family from Tonopah, Nevada, and catching frogs with my bare hands,” Zimmerman said. “I also appreciated that the project leader designed the survey so that anyone could participate without any particular knowledge about Columbia spotted frogs or specialized technical skills.”
Partnerships have been instrumental to the success of the PIT tagging program over the past 14 years. One of those partners, The Nevada National Heritage Program, is a clearing house for data on Nevada’s diverse population of at-risk species, including for the Columbia spotted frog.
Program director Kristin Szabo said the tagging data collected is used to help understand how at-risk a species is in Nevada, and to inform local land-use decisions and conservation planning.
Besides tagging and monitoring, the on-the-ground conservation actions by landowners, agencies and others helped recover the populations of Columbia spotted frogs. This included restoring ponds for habitat and limiting erosion caused by livestock overgrazing.
Mother Nature also played an important role this year when increased precipitation broke the cycle of drought ravaging the region for the past five years. With PIT tagging, biologists can see spikes in a population after a particularly good water year and a sharp decline after bad ones. Armed with this data, Mellison said he expects the 2018 survey to be a banner year for the frogs.
“With the commitment of the agencies to conserve this species through our Conservation Agreement and Strategy, the Columbia spotted frog has a bright future ahead of it,” he said. “By collecting the data through our PIT tagging efforts, the agencies will be able to better understand threats that may be causing declines and adopt management strategies to alleviate those threats to conserve the species.”
Through partnerships and dedicated volunteers, the Columbia spotted frog is a true success story, but the work doesn’t stop here. Mellison says the tagging efforts will continue for the foreseeable future in order to maintain a stable, healthy population.
Partners for Frog Week include the U.S. Fish and Wildlife Service, U.S. Forest Service, Nevada Department of Wildlife, Bureau of Land Management, University of Nevada—Las Vegas and Nevada Natural Heritage Program. This article was originally appeared here as a news release on the Fish and Wildlife Service Website.