Written by The Business Journal Staff
The California red-legged frog, named for its colorful legs and belly, vanished from the Yosemite National park more than 40 years ago. It is the type of frog featured in Twain’s short story “The Celebrated Jumping Frog of Calaveras County.”
Western pond turtles — missing from most of the park for 50 years — are also being reintroduced to Yosemite, both under a partnership with the San Francisco Zoo & Gardens, officials announced.
“This is a landmark event for Yosemite National Park and a historic opportunity,” said the park’s Superintendent Don Neubacher.
The zoo has begun nurturing frogs in a permanent breeding center. Officials say they already released 2,000 tadpoles in March.
Over the next three years, thousands of tadpoles and adult frogs from the center will be transported 200 miles to be set free in the park’s lush meadows, alpine lakes and winding Merced River.
The frog disappeared from Yosemite in part because non-native, predatory bullfrogs first introduced to a reflection pond spread throughout the valley and, over time, gobbled them up, officials said.
The insatiable bullfrogs have since been eradicated from the park, clearing the way for the red-legged frog’s return, said Rob Grasso, an aquatic ecologist at Yosemite who spearheaded the project.
“Now that they’ve been removed, we know the red-legged frog will do well,” he said.
Red-legged frogs grow to 2 to 5 inches long. They are the largest native frogs in the West — known for communicating in short, soft grunts — and listed as a federally threatened species.
Hundreds of adult Western pond turtles will be moved to Yosemite Valley in the next few years. The first 10 will be released in June, fitted with radio transmitters to track them and discover their preferred habitat.
The turtles can grow to seven inches long, and park visitors may see them basking on logs or rocks. Some of the turtles still have been found in the remote Hetch Hechy area of Yosemite, but not on the valley floor.
Federal authorities are considering whether to give the turtles in California protection under the U.S. Endangered Species Act.
Park officials cite a number of mismanagement practices over a century that may have caused both species to vanish.
Rangers clearing fallen trees and other debris from the Merced River’s banks in the past may have inadvertently removed critical habitat, officials acknowledged. But rangers say improved practices have restored park conditions for both the turtle and frog to thrive.
Officials said an abundant raccoon population may also have preyed on the turtles and frogs.
This is the latest effort to restore native animals to Yosemite. State wildlife officials in 2014 reintroduced bighorn sheep to Yosemite’s backcountry after overhunting and disease spread by domesticated sheep herds wiped them out.
“Maintaining the natural balance of biodiversity in the park is important to its long-term well-being and to sustaining opportunities for visitors to experience the park as nature intended,” said Frank Dean, president of the Yosemite Conservancy, which has contributed $540,000 to the park’s aquatic animals.