"Part of SF Mountain Lake being returned to wetland"
2014-03-06 by David Perlman for "San Francisco Chronicle" [http://www.sfgate.com/bayarea/article/Part-of-S-F-Mountain-Lake-being-returned-to-5292072.php]:
Fifteen goats have been munching on the underbrush in a section of the Presidio, clearing the way for a future Shangri-La where turtles, frogs and other wild creatures can thrive as their ancestors did in what was once a fertile wetland.
The goats have played a key role in a pioneering venture on the edge of San Francisco's Inner Richmond District: the transformation of a long-neglected little valley next to historic Mountain Lake into a model site for amphibious animals, and the plants and insects that sustain them.
"We're returning the lake's arm into the haven it once was for generations of wildlife going back long before the 1800s," said Terri Thomas, the Presidio's conservation director and longtime protector of its natural resources.
The narrow water-filled arm on the eastern shore of Mountain Lake disappeared when home construction was booming in the Richmond more than a century ago.
Over the years, the lake itself became filled with debris, toxic pollution, alien fish, pet shop turtles - even an alligator. But as part of the larger restoration project, its polluted bottom has been dredged and its western shoreline thickly planted with trees and new vegetation.
Goats clear the ravine -
Today, the lake's East Arm is a shallow ravine, cleared by the goats from its thickets of French broom, Cape and English ivy, and a jungle of other invasive plants. The area can be seen by passersby through a sagging chain link fence along West Pacific Avenue.
The goats had been brought in to clear that jungle when 200 nonnative eucalyptus trees were removed to give them room to dine. The additional sunlight afforded by the trees' removal will help establish plants that are being brought in for the restoration.
"It's a great opportunity for bringing back the biodiversity that once was there," said Jonathan Young, a biology researcher, graduate student at San Francisco State University and leader of the project to return life to the East Arm and Mountain Lake.
Young will oversee the return of animal life to the East Arm.
Among the first on his list is the California red-legged frog, a species that once thrived in the East Arm, and has long been threatened by overdevelopment of its wetland habitats throughout the state.
The tiny Pacific chorus frog will also be reintroduced, and like so many other amphibians being brought back, will dine on a variety of spiders, beetles, flies and their ilk that inhabit the East Arm.
Cutting back on mosquitoes -
Neighbors on the city side of the East Arm have long been pestered by mosquitoes during the damp season, and the hungry amphibians should help ease that problem by snapping them up along with their larvae, Young said.
"The East Arm will also make great habitat for the San Francisco western forktail damselfly," he said. "It's one of the rarest damselflies in North America. It's beautiful, and there's only one very tiny population left here, out by Fort Point."
The colorful insects also consume huge numbers of mosquitoes and the nymphs, their water-born young, are great consumers of mosquito larvae.
Also on the return list are Western pond turtles, a native species long gone from Mountain Lake. Young pond turtles, extremely rare in California, are being reared at the San Francisco Zoo and new nesting grounds will be built on the sandy slopes of the East Arm to welcome them after they've reached maturity in the lake.
Turning the East Arm into the living wetland it once was calls for water, and the planners have that figured out.
"There's bedrock deep beneath the East Arm," said Brian Hildebiddle, a Presidio ecologist and stewardship coordinator. "Back in the 1890s it was filled in, but when that fill is removed there will be groundwater and runoff from the golf course.
"So even in drought times there will be water here, and once we've planted, it'll only take a month for everything to start growing," he said.
Wild strawberries, cow parsnips, cinquefoil and the pink honeysuckle favored by hummingbirds are on Hildebiddle's list of 30 species of plants he intends for the low-lying ground that will soon be contoured by some 6,000 cubic yards of fresh earth.
Acres of wetland -
"By this time next year, birds will be nesting, plants will be growing, and we'll have 3 or 4 acres of wetland right where we're standing," he said.
Michael Boland, the Presidio Trust's chief of planning and projects, doesn't hide his enthusiasm when he talks about the future of the East Arm project.
"Restoring the East Arm as protected wetland, with the plants and animals living their lives and thriving there, will give us a really unique way for the public to enjoy and understand the life cycles of everything," he said. "It's really vibrant wildlife, and we want people who see it to feel like the woodland is wrapping around them."
No comments:
Post a Comment