A team of biologists — including members from the U.S. Geological Survey, California Department of Fish and Wildlife, U.S. Forest Service, University of California, Los Angeles, Endemic Environmental Services Inc., Citrus College and San Diego Zoo Global — worked together recently to find and rescue the last remaining reproductively viable population of southwestern pond turtles in the San Gabriel Mountains.
The area, which was devastated by the Bobcat Fire over the last two months, is at risk of mudslides and debris flows that could have an extremely negative impact on the aquatic habitat for the turtles.
The team spent days in the field, with the goal of removing some individuals of the native species from the river, racing against time before winter storms place the little reptiles in danger.
“Seventeen of the 20 largest California wildfires have occurred over the past 20 years,” said Rich Burg, environmental program manager, California Department of Fish and Wildlife. “Megafires like these have created devastating ecological conditions even after the fires have been extinguished. In this case, we have a situation where there is little or no vegetation left on the slopes, impacting terrestrial habitat. It is likely that there will be significant sediment flows into the West Fork of the San Gabriel River, which could fill in existing refugia pools and change water chemistry. This can negatively impact the pond turtle population.”
The pond turtles include two recently recognized species that together comprise the only freshwater turtles native to California, and they are thought to be increasingly at risk of extinction. Both species are currently being assessed by the U.S. Fish and Wildlife Service for potential listing under the Endangered Species Act. The southwestern pond turtle, which is distributed in coastal freshwater habitats from the San Francisco Bay Area to northern Baja California, Mexico, is now rare in Southern California. It faces major risks to its survival, including habitat loss, invasive nonnative predators, and competitors like crayfish, bullfrogs, African-clawed frogs, and largemouth bass, which compete for natural resources and often consume the tiny, quarter-sized turtle hatchlings.
“We have become increasingly concerned over the status of our native pond turtles,“ said Ann Berkeley of the U.S. Forest Service. “They are a small species with a great deal of charm, and their presence in our local creeks is important to maintaining the biodiversity in small waterways that are found throughout our Southern California mountains.”
Wildlife biologists were able to locate and rescue eight southwestern pond turtles over two weeks. “This is not the first such effort, and almost certainly will not be the last,” said Brad Shaffer, UCLA distinguished professor and director of the La Kretz Center for California Conservation Science. “These turtles will also be part of a range-wide genomic analysis of variation across the species that we are conducting with the CDFW and USGS to better understand and conserve the population, which is the last known of this species in the San Gabriel River.”
The turtles are being relocated to San Diego Zoo Global.
“San Diego Zoo Global and other California zoos have been working to headstart western pond turtles for a number of years,” said Robert Fisher, a supervisory research biologist with the USGS. “Ten years ago, we collected gravid female pond turtles from the Sweetwater River at the Sycuan Peak Ecological Reserve and brought them to the San Diego Zoo to lay their eggs. The offspring were head started at the Zoo, then released back into the reserve, and are doing well.”
The San Gabriel Mountain turtles will be cared for at the San Diego Zoo until an assessment of their habitat is made after this year’s rainy season. When their habitat is deemed secure, they will be returned to the wild. A similar effort removing turtles from Lake Elizabeth in eastern Los Angeles County and returning them after a year in captivity at UCLA and the Turtle Conservancy in Ventura County was also successful.
“The effort to save these small turtles, and the bigger effort to save California’s at-risk species, is not something any one of us can do alone,” said Paul A. Baribualt, president/CEO, San Diego Zoo Global. “Working together, as allies, we are working to save these little reptiles—and we hope that our communities will join our efforts, and help all of us to make our local habitats safe for these species in the future.”