March 31, 2008
Fate of Snake Depends on Frog
Critters that leap, slither and crawl throughout the world are on the brink of extinction, but efforts to keep them from croaking are under way.
It is estimated by conservation and environmental groups that up to one-third of the world's amphibian population is nearing extinction. With hopes of combating this demise, they have named 2008 the Year of the Frog.
In response, volunteers and competitors in the Golden Gate National Recreation Area have begun Big Year, a contest to see and save the Bay Area's 33 endangered species, came out to Mori Point in Pacifica recently to help a reptile and an amphibian whose futures are uncertain.
The 110-acre refuge is a safe haven for the threatened California red-legged frog and the endangered San Francisco garter snake, both teetering on the edge of extinction.
Biologists and ecologists, with the added help of volunteers, have constructed three ponds since the GGNRA annexed Mori Point in 2000. The rain and groundwater pools provide an annual wetland habitat for the iridescent blue-and-crimson snake and its primary food source -- the red-legged frog.
The relationship between the two species is fragile. When the population of the frog declines, so does the population of the snake.
But conservation efforts have proved successful at Mori Point, which is flanked by a manicured golf course, housing and development. In addition to habitat, the ponds also generate a nursery for the red-legged frog's egg masses.
As tadpoles emerge, so does food for the snake.
"The most important thing we can do to help the snake is beef up the frog population," said Sue Gardner, program director for the GGNRA Parks Conservancy. "And we've already been finding red-legged frog egg masses as we near the completion of the ponds."
Volunteers are helping ensure the survival of these endemic species by planting native coyote bush, bee plant, sagebrush and small trees along the border of the ponds, which the frogs need to attach their egg masses.
Steve Price, a Big Year competitor, gets out of bed at 6 a.m. on Saturdays and Sundays to take part in the challenge of helping to save as many species as he can.
"This is more beautiful than sleeping in," he said. "I can come back here and look at one of these plants, and say that I planted it and it's still growing, helping these species."
Added volunteer Susan Goldsborough, "Frogs are so threatened, and I've always loved them like people love their dogs."
She said she saw a garter snake in 1967 in San Mateo.
"It was so beautiful, I'll never forget it," she said.
Historically, destruction and degradation of wetlands and estuaries -- the frog's main habitats -- have been the main culprits in its struggle.
But recently, scientists and biologists have found the species' decline is also caused by a rapidly dispersing infectious disease called chytridiomycosis, which permeates the thin porous skin of amphibians. The disease is caused by a fungus called Batrachochytrium dendrobatidis, or Bd.
The deadly fungus comes from the African claw frog. The frogs were brought here for pregnancy testing and medical research.
Although restoration is important, the effect of habitat destruction, climate change, pollution and Bd can't be dealt with solely in the wild. Scientists and biologists have begun addressing these concerns and creating habitats in captivity.
"There are at least 6,000 imminently threatened amphibians. If we lose them, we lose a future of medical advances and ecosystem recovery," Feldman said. "So we're creating a sort of Noah's Ark for them. We're studying what they eat, where they live and where they breed to succeed in this enormous challenge."
"This could be the largest extinction since the dinosaurs if we don't do something," he added.
There is currently one garter snake in captivity at the San Francisco Zoo.
"We're asking people to change their behaviors, so seeing the snake is a good thing. It will help people form a personal connection to what they're doing," Gardner said.
Added Feldman, "These disappearances are no longer enigmatic. The magnitude of Bd is dangerous, it's spread to every continent."