SCIENCE WEDNESDAY -- September 11, 2013 at 5:36 PM ET
The Frog and the Pot Farmer Battle for Land in the Santa Monica Mountains
A plan to reintroduce the red-legged frog in Los Angeles County's Santa Monica Mountains has been complicated by an unforseen factor - illegal marijuana farms. Photo by USGS and Adam Backlin
It was the red-legged frog -- a fist-sized, ridge-backed, mud-colored amphibian -- that is believed to have inspired Mark Twain's 1865 classic story,"The Celebrated Jumping Frog of Calaveras County." The story featured an athletic frog named Dan'l Webster and an opportunistic gambler who filled the frog's mouth with a handful of buckshot to win a bet, handicapping its jumping abilities and making off stealthily with $40.
Known as Mark Twain's first major success, the story harkened back to a time when the red-legged frog's range covered large swaths of California, stretching from Baja California north to the Bay Area.
But in the 1800's, the species' numbers were slashed due to a taste for frog's legs among miners in the Sierra Nevada and San Francisco. And then further devastated by habitat loss, pollution, sport fishing and predators like the larger non-native bullfrog. Since Twain's time, its range has shrunk 70 percent, and it has completely disappeared from 24 of the original 46 California counties it called home, according to Collette Adkins Giese, the amphibian and reptile staff attorney at the Center for Biological Diversity. It was listed as threatened under the Endangered Species Act in 1996.
Now, a new plan to reintroduce the frog in Los Angeles County's Santa Monica Mountains has been complicated by another factor -- illegal marijuana farms.
The frog and the pot farmer, it turns out, share an affinity for certain things -- among them, land undisturbed by humans and deep streamwater.
Katy Delaney, a wildlife ecologist with the National Park Service, has plans to relocate eggs from a rare population of red-legged frogs in the Simi Hills -- home to as many as 100 frogs -- to a site in the Santa Monica Mountains, the range that cuts through Los Angeles and runs along the Pacific Ocean. Her agency is partnering with California State Parks, USGS, the US Fish & Wildlife Service, and the Santa Monica Bay Restoration Commission on the project.
Using their fingers, Delaney and her team plan to carefully tease out hundreds of frog eggs from an egg mass in the Simi Hills and transfer them to a stream in the Santa Monica Mountains. The eggs will be enclosed in mesh containers suspended along the surface of the water. The containers are designed to allow in light, oxygen and nutrients from the stream, while protecting the eggs from predators until they hatch into tadpoles and grow large enough to be released.
Delaney has been searching for the perfect site, one that lacks invasive species like crayfish and contains undercut banks, good vegetation and deep pools of year-round water.
"We're also looking for places where there's not a lot of access," Delaney said. "We don't want people going in and getting curious about our pens." After the first few months, even Delaney herself and her team will only visit occasionally to avoid disrupting the animals.
But marijuana farms have limited her choices, making otherwise appealing spots hostile to the frogs.
Bonnie Clarfield, a supervisory park ranger for the Santa Monica Mountains National Recreation Area, has patrolled the area since 1989. Small-scale marijuana groves have always been a problem, she said, but it wasn't until 2003 that the first "drug trafficking organization cultivation", as she calls it, was discovered.
These are large-scale, lived-in farms that are usually guarded by weapons, she said, including SKS rifles, high-power BB guns and knives. As many as 30,000 marijuana plants were pulled from one cultivation in Topanga. Due to these operations, she now routinely wears full tactical gear for safety, including a ballistic vest, and carries a rifle in the park.
"I never thought I'd be using military tactics to do my job as ranger," she said.
Since 2003, more than 100,000 plants have been eradicated from the Santa Monica Mountains. And seven national parks are facing similar problems, Clarfield said, including Death Valley, Yosemite, Redwood and Sequoia and Kings Canyon National Parks.
Clarfield describes the scene at an average growing site: bright green marijuana plants alongside brownish stems and leaves drying out in the sun. The odor from septic pits mixed with the skunk-like smell of the plant. Camouflage materials like netting, along with batteries and trash clutter the ground. Propane and radios are common, as are groceries, camping stoves and tents. And then there are powerful chemicals to ward animals from the crop.
Christy Brigham, chief of planning, science and resource management for the Santa Monica Mountains National Recreation Area, has also been tracking the problem. Her team too has found various herbicides and rodenticides - poisons used to kill weeds and rodents. That poison, she said, gets consumed by deer mice, wood rats and rabbits and then travels up the food chain to infect the larger animals that roam the area, such as bobcats, coyotes and mountain lions.
Plus, native vegetation like California lilac, California sagebrush and purple sage are routinely yanked from the ground to clear large areas for planting.
"They're just in piles. Little dead slush piles there, adjacent to the marijuana farm," Brigham said.
Fire pits are also common -- a particular concern, given the arid climate and the area's history of dangerous wildfires.
"Everything our mission stands for in the National Park Service, this undoes," Clarfield said. "I don't care if they're growing tomatoes. What they're doing and the way they're doing it is hurting the park. We're supposed to be conserving the scenery, the national historic objects and the wildlife they're in. This activity of theirs is just counter to our mission."
Another sure sign of a marijuana farm is water being illegally diverted from a nearby stream or from water fixtures along roads and highways, Brigham said.
"They make a little dam in a creek, and they run irrigation tubing from there," Brigham said. "In one case, they tapped into a fire hydrant on a road and ran tubing from it. But the typical pattern is to use an existing creek."
One stream site that would have otherwise topped Delaney's list for red-legged frog habitat was rejected due to black PVC tubing pumping water from the stream.
Still, Delaney's hope in the next few years is to establish a successful breeding population of red-legged frogs in the Santa Monica Mountains, like the one in the Simi Hills.
"We could literally be one major drought away from losing that population," Delaney said. "And the range is going to be restricted more and more."
The frogs, which have permeable skin that easily absorb contaminants in the water, are considered an important indicator species of the health of aquatic areas.
At about 5 inches long, the red-legged frog is the largest native frog in the state. It's muscular hind legs make it a fantastic jumper, and it gets its name from a reddish coloring on its hind legs and abdomen.The area's last known frog was seen in the early seventies in Cold Creek, a year-round stream that flows through the Santa Monica Mountains and empties into Malibu Creek.
"Because it requires clean water and intact waterways, by protecting the frog and making sure we have clean waterways, we're protecting ourselves and our water," Giese said. "In many ways, it's a canary in the coalmine situation...If the frog's habitat is so polluted that it can't survive, that's a real sign that we're treating our waterways in a way that's not sustainable."
Photo credit: At about 5 inches long, the red legged frog is the largest native frog in the state, but its numbers have been decimated by habitat loss, pollution and predators. Photo by Katy Delaney.