2012-03-20 "SFO warns trespassers in frogs' protected wetland" by Peter Fimrite from "San Francisco Chronicle"
[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2012/03/19/BA8F1NN1A8.DTL]
The dog walkers, teens and transients who gallivant around in the greenery near San Francisco International Airport are going to be cited for trespassing if they venture out again into the protected grassland, San Francisco police and airport security announced Monday.
 The fenced-off piece of land, owned by the city of San Francisco and squeezed between Highway 101, the Caltrain tracks and Interstate 380 in San Mateo County, is sensitive habitat for the San Francisco garter snake and the California red-legged frog, both listed under the U.S. Endangered Species Act.
Airport spokesman Michael McCarron said homeowners whose property abuts the wetland were recently sent a letter warning them that trespassers would be subject to arrest and an unspecified fine.
 "It's a protected wetlands area that we are responsible for maintaining," he said. "We don't want the habitat to be destroyed."
 The 200-or-so-acre strip - which is crisscrossed with power lines, meters, and power and pumping stations - has been trod upon for decades by the locals. Except for a few small city parks, the wetland is the only open space in the mostly working-class area of San Bruno and Millbrae, west of Bayshore Boulevard.
A 2007 study found a large, healthy population of garter snakes and red-legged frogs in the area. The frog is estimated to have disappeared from 70 percent of its range in California. The local subspecies of the garter snake has been endangered since 1967.
Despite signs declaring the area "sensitive habitat" where "no trespassing" would be allowed, holes have been cut in the security fence and rudimentary forts, plank bridges, homeless camps, beer cans, motorbike tracks and canine deposits have been discovered around the sloughs and amid the brush, airport officials said.
 Some residents have built gates in their backyard fences and one family extended a concrete patio into the protected area, officials said.
"There is just generally the unintentional mayhem people can bestow on an environment," said Karen Swaim, a herpetologist hired by the city to monitor the site.