All for the Snakes
In early March, on a beautiful clear day, I visited Mori Point, guided by Sue Gardner, program director of GGNPC’s Site Stewardship Program. The 110-acre park, on a headland whose fate had been in limbo for decades, finally joined the GGNRA in 2002, after purchase by the Trust for Public Land with help from the Pacifica Land Trust, Coastal Conservancy, and local community members. The purchased parcel is bordered on the north by the San Francisco City-owned Sharp Park Golf Course--once saltwater marsh--and on the east by a small housing development. From this low-lying area the property rises to a prominent blufftop, where Sue and I enjoyed a breathtaking view up the coast to Mt. Tamalpais and, faint in the distance, Point Reyes. Below us, at the bottom of a new set of 198 timber steps, a recreation path--part of the Coastal Trail--stretched atop a seawall toward Pacifica Pier. And downslope to our right was a mid-elevation area of gentle incline--the “heart” of Mori Point and prime San Francisco garter snake habitat.

This heartland is marked now by three freshwater ponds, all constructed by the GGNPC as refuges for the red-legged frog within the past year in the first phase of a two-phase restoration project. Totaling more than 1,200 square feet in surface area, they were designed with the help of a hydrologist to ensure that they will hold water for six months--a requirement of the frog’s breeding cycle. The frogs have already discovered the ponds and have been depositing clusters of gelatinous eggs in them and in nearby Laguna Salada, a natural pond adjacent to the seawall. The chunky little polliwogs will then, hopefully, become foraging fare for the snake. (The snake also eats western tree frog young, but it prefers the larger--and perhaps tastier--red-legged tadpoles.)

In a sense, the seawall created the snake and frog habitat here, because its construction changed what had been saltwater wetlands to freshwater marsh. As housing was built inland, the snakes moved shoreward and came to rely on the marsh landward of the seawall. When the GGNPC built the three ponds in 2007, it expanded this habitat. The lower ponds are fed by the surrounding watershed and tied in with groundwater. The southernmost “perch” pond, finished last October, is fed only by rainfall and runoff and has a clay bottom to prevent percolation of its precious liquid.

The restoration project has been long in the planning. One of the first tasks was to undertake a census of the snake. This was done four years ago, with traplines set by biologists. Only seven individuals were found, said Sue, “but they were male and female, and there was age stratification”--an excellent demographic, promising reproductive potential. Two years ago 13 snakes were counted in a second census. “So all we can say for sure,” Sue noted, “is that the population is increasing. But that’s what we want to see.”

After this crucial groundwork was completed, the restoration project was launched in July 2007. The first phase focused on controlling invasive nonnative plant species, particularly French broom and pampas grass; removing debris left over from prior land uses; erasing informal trails and beginning construction of a streamlined trail system; and building the three ponds.

Before brush clearing, grading, and digging of the ponds could begin, a team of biomonitors made sure the snake wasn’t in danger. “When the weather warms up,” Sue explained, “the snake likes to take refuge in underground burrows. So the biomonitors went in front looking for gopher holes and excavated gently, by hand, each one to make sure there were no snakes in them. When we thought we had everything excavated, we put snake-exclusion fencing around the area so they couldn’t get back in, with a little exit hole in case any were missed--and we left that up until the ponds were finished.”