Student researchers Gerardo Avila and Samantha Hubbard are studying a population of desert tortoises to monitor their behavior and evaluate how their habitat is impacted by climate change.
The Cal State Fullerton biological science students are observing and tracking wild tortoises at the Philip L. Boyd Deep Canyon Desert Research Center, in the shadow of the Santa Rosa Mountains, near Palm Desert.
Due to the area’s changing and rising temperatures, the students are using cameras to monitor tortoise activity near the burrows where they dig, often under creosote bushes that dot the landscape.
“We’re interested in seeing the impacts of climate change on this population since they live in a drier and warmer environment compared to other tortoise populations,” Avila said.
Tortoises spend 95% of their time in burrows that serve as a refuge from extreme temperatures and bask in the sun on burrow aprons. Burrows also are ideal for brumation, where cold-blooded tortoises remain in an inactive state for long stretches of time, said William “Bill” Hoese, professor of biological science, the students’ research mentor.
The researchers also are investigating tortoise movement around the Deep Canyon landscape throughout the year.
“How the tortoises behave and respond to current conditions may be an indication of how the rest of the species, which mostly live in the nearby Mojave Desert, may be impacted by future climate change,” Hoese said.
The CSUF researchers are working with Chris Tracy, reserve director at Philip L. Boyd Deep Canyon Desert Research Center, a UC Riverside field station, on the long-term study. Other collaborators include scientists from the U.S. Geological Survey, who for decades have been studying desert tortoises, a threatened species under the 1990 Endangered Species Act.
Tracy, whose research interests focus on the physiological ecology of desert animals and plants, explained that because the habitats at Deep Canyon are extreme for the tortoises, it’s important to understand their behavior and population.
Tracking location transmitters have been placed on some tortoises so the researchers can monitor their every movement, what types of burrows are used in different seasons, and perhaps find more burrows and tortoises, Tracy said.
“We’ve known there is a small population in Deep Canyon for many decades, but no one has done a thorough estimate of how many tortoises are here or what the status of the population is,” Tracy added.
“Because of this project, we now know that there are at least 12 tortoises in Deep Canyon — an area over 5,000 acres — and we suspect that there are more.”
The researchers also set up trail cameras at burrows to observe both the activities of the tortoises, usually solitary creatures, as well as other animals that might use the underground shelters.
“I want to figure out which of the other species in the region are using them — and why,” said Hubbard, a research scholar in CSUF’s McNair Scholars and Louis Stokes Alliance for Minority Participation (LSAMP) programs.
“Researching the tortoises and the animals that interact with them can help maintain their populations and the ecosystem as a whole.”
Cal State Fullerton’s involvement in the project began in the summer of 2021 with biological science student Megan Peukert, selected for UC Riverside’s Natural Reserve System internship. She set up burrow cameras with Tracy and the USGS team. Peukert worked with student researchers to maintain cameras during 2021-22 when she was a CSUF Summer Undergraduate Research Academy (SUReA) scholar.
Avila began his fieldwork last summer also as a Natural Reserve System intern. He worked with the USGS team to apply radio transmitters on four tortoises and has been tracking the slow-moving reptiles ever since. He also is maintaining the cameras that were placed in the summer of 2021 and makes frequent trips to the desert with Hubbard, who joined the research team in the fall.
Hoese’s students are planning careers in ecology and environmental biology research, and through this project, are getting hands-on experience and learning how to work with outside collaborators.
“They’re being exposed to loads of new skills and approaches to conducting fieldwork and research,” noted Hoese, CSUF’s 2021 Outstanding Professor and a 2023 CSU Wang Family Excellence Award recipient.
Avila, selected with Hoese for the Council on Undergraduate Research’s inaugural Scholars Transforming Through Research Program, shared that preliminary findings contradict established desert tortoise literature. The researchers plan to have some results this spring.
“We’ve observed plenty of tortoise activity in the summer, including fighting males, which is the hottest time of the year and normally when tortoises would stay in their burrows to avoid the heat,” said Avila, who plans to graduate in May.
“These tortoises keep surprising us. It’s a treat to discover what they are up to in their desert environment.”