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Posted by desiree on August 01, 2002 at 12:13:15:
Tough Shells Cannot Protect Turtles' Future
Loss of habitat in the Santa Monica Mountains threatens Western pond species.
By STEVE HYMON
TIMES STAFF WRITER
July 27 2002
It is a scorcher of an afternoon, the kind of day when it's hard to imagine water, much less pond turtles, left anywhere in the Santa Monica Mountains.
In the heat, Rosi Dagit and her small crew of volunteers hike up a dry creek to a sandstone gorge where--surprisingly--a small pool of water has survived the drought. It's not much. There are probably bigger bathtubs in the mansions that dot nearby hills.
Dagit, a biologist, crawls up to the water and points. On cue, a tiny green head pokes through the surface. It's a baby turtle, about the size of a dollar pancake. It takes a quick breath and vanishes into the murk. Another soon emerges and does a passable version of the breaststroke.
"They are the cutest things," says Dagit. "I could sit and watch them all day."
She's correct. On a scale of one to 10 for cuteness, the turtles warrant an 11. And that's just one reason they're in trouble.
Dagit works for the Resource Conservation District of the Santa Monica Mountains, and she has brought her charges to the creek as part of a two-year study of the elusive reptiles. Among the questions she hopes to answer: How many turtles live in the Santa Monicas? What types of habitat do they need? What do they eat and who eats them? Where do they go on Saturday night?
Dagit and her 40 or so volunteers plan to spend hundreds of hours observing turtles, an activity that seems leisurely but actually involves filling out a lot of forms.
The real data bonanza will come in the fall when rice-sized radio transmitters are attached to 10 adult turtles, which are about 6 inches long. This will allow Dagit to continuously track their movements. That way, she'll learn how they spend Saturday night, and where--and, perhaps, with whom --they awaken on Sunday morning.
Western pond turtles are native to the West Coast and were once common in streams from the Canadian border to Baja. Today, they are listed as endangered in Oregon and Washington, but California has designated them a "species of special concern."
There is some good news. Dagit and other biologists believe that pond turtles can be saved if--and it's a big if--people are willing to understand the problems facing the reptiles and will make a few small sacrifices.
The turtles' biggest problem is habitat loss, caused by the draining of wetlands and by development. The soggy coast of Washington, for example, is seemingly ideal turtle habitat, but only 17 pond turtles have been found there since 1986. "Last year we even had two turtles that were shot," said Frank Slavens, who works with the state's turtle recovery project.
In Southern California, about 2,000 turtles remain, and Dagit believes that there could be as many as 10 small populations in the Santa Monicas. The habitat problem here, she suspects, involves the females.
Before laying their eggs in the autumn, the females take a long drink of water and depart for higher, drier ground--sometimes traveling a mile or more. After they've selected a site, the turtles release the water to soften the soil. Then they dig and bury their eggs.
Though many creeks in the Santa Monicas are in good shape, Dagit suspects that development has robbed the turtles of nesting sites throughout their range.
The mothers are picky, and if they can't find a suitable nesting site, they don't nest. That means no baby turtles, which means the overall population drops.
If they do nest, success is hardly ensured. After hatching in the spring, the babies must journey back to water through a gantlet of predators that includes raccoons, coyotes, bobcats and bullfrogs. Often, the moms are also eaten.
In the Santa Monicas, the turtles are fortunate, because a few mountain lions remain, and the big cats eat the raccoons.
"If you live in the mountains and you want to help turtles, animal-proof your garbage," to discourage raccoons and other animals, said Dan Holland, the world's foremost expert on pond turtles. "Another thing I can't overemphasize is that people have a really bad habit of buying turtles as pets, and when they get tired of them they throw them in the nearest pond."
Holland has found 29 species of exotic turtles in pond turtle habitat on the West Coast. And as California has become home to turtles from all over the world, the turtles that evolved here for more than 1 million years have been disappearing. Why? Exotic turtles often bring exotic diseases that kill pond turtles.
"These pet turtles belong in the part of the world they originated in," said Holland. "How would Californians feel if people were harvesting thousands of our native turtles and shipping them to Florida as pets?"
Dagit, for one, believes that the situation for the native turtles is far from hopeless. But she is concerned about how a drought could affect them. She worries, too, about the problem of cute little turtles being plucked from streams and tossed into fishbowls.
More than anything, she frets about development in the local mountains. "People look at the Santa Monicas and say there's so much space left, but that's from the perspective of a human, not all the other things living here," she said. "We really don't know how it all fits together."
No one suggests that the entire ecosystem will unravel should pond turtles disappear. No one, in fact, really knows exactly what impact turtles have on an ecosystem.
This much is known: For hundreds of thousands of years, pond turtles endured in Southern California. They have been washed out to sea by winter storms and sandblasted by years of drought.
But there were always a few that had the strength, will and tenacity to climb back into the mountains and find a small pool of water shielded by the sun.
The turtles of the Santa Monica Mountains, scientists say, are proof that evolution is not a sprint, but a marathon full of hurdles.