Homestead Pond
San Mateo County, California



Located in a small valley in San Mateo County, California, Homestead Pond covers a mere 12 acres but includes a surprising diversity of natural community types. The site is a microcosm of remnant high-quality habitat interspersed among areas of heavy human disturbance.

The site is at the southern end of the San Francisco Public Utility Commission's vast Peninsula Watershed holdings, which cover 23,000 acres and stretch from Redwood City north to Pacifica. Although in close proximity to dense urban and suburban development and bordered on the east by Interstate 280, the Peninsula holdings are largely closed to public access except along a few roads and trails.

Homestead Pond straddles the San Andreas fault, and is bordered on the west by the steep wooded slopes of the Santa Cruz Mountains. Gentle hills rise to the east, across Old Canada Road and Interstate 280, within Edgewood Park.

The northern part of the site is nearly level and mostly open. Serpentine bunchgrass of good quality grows on thin soils among numerous small rock outcrops. Some weedy species are encroaching from the east, allegedly encouraged by nitrogen enrichment related to automobile exhaust on the adjacent freeway. Soils derived from serpentinite are normally low in nitrogen, which puts many non-native and invasive plants at a competitive disadvantage. The proximity of a major highway may have disrupted this balance.

Just to the south is a majestic oak woodland, with old valley oaks and coast live oaks spreading their moss-draped limbs. Here the terrain is rolling and the soils are derived from rocks of the Franciscan formation, and there is no serpentinite; the boundary is quite abrupt and marked by a narrow rocky and ephemeral stream channel. On these more conventional soils native grasses have not done as well and they have largely been replaced by Eurasian annuals.

Oak Woodland

mixed oak woodland,
with serpentine grassland in foreground

On the southern edge of this oak woodland the low hills drop away to a table flat area. Here, old attempts at mining carved away the rock below the hills, leaving a small pond and a low surrounding terrace. Blue gum eucalyptus, native to Australia, tower over the edges of the pond and drop their thin bark to form a dense ground cover.

eucalyptus

eucalyptus encroaching on Homestead Pond

Although man-made, on certain days the pond is a magical place. In the spring, western pond turtles drop into the water from fallen logs. In mid-winter newts are everywhere, swimming in the pond and walking among the wet grass at the margins, like little living rubber toys with bright orange bellies. An occasional Pacific chorus frog leaps through the vegetation.

Western Pond Turtle

Western pond turtle, Actinemys marmorata

The pond draws it's water from small streams which flow to either side. The main channel forms the western boundary of the site, and mostly it supports a native riparian woodland with coast live oak and arroyo willow. A smaller tributary flows along the eastern edge of the site, mostly lined by eucalyptus, before curving west through a more open area to divide the serpentine bunchgrass and oak woodland as mentioned above, before it joins the larger stream. Just south of the pond, a small and shallow channel carries high flows across the site, feeding a small marsh along the way, before dropping toward the larger stream to the west. During the heaviest winter rain events some of this water flows into the pond.

Continuing to the south walking becomes more difficult. Here oaks intersperse with Monterey cypress planted in straight rows, where scattered bricks on the ground betray the former presence of a structure... thus the name, Homestead Pond. Whatever once was built here is mostly gone, leaving only too-straight borders along some treelines, an abundance of non-native and weedy plants, and in some places thickets of encroaching shrubs. Then, suddenly, one emerges into another grassland. On the northern edge it is a very good grassland, blooming densely in the spring with lupine and California poppy and with tussocks of purple needlegrass. In the lower central part of the grassland weedy species again become dominant before grading yet again into a wetter area of somewhat better quality, and then at the very southern tip of the site, into a tangled interspersion of coyote brush scrub, oaks, and eucalyptus.

Grassland

needlegrass and lupine

That's a lot of diversity for such a small site. It takes longer to describe it all than it does to walk across the entire place.

It could be even better with a little work, and that's exactly the plan. The idea is to preserve the remnant high-quality communities scattered throughout the site, removing invasives and otherwise managing as appropriate. In degraded areas, the approach will be much more intensive, in some cases removing everything down to the bare ground and starting over.

Later this year, the eucalyptus will be cut and removed. The cypress will be girdled and left to fall on their own. Young oaks will be planted into the newly open areas, and willows along the riparian corridors. Native grasses and forbs will be seeded into the understory.

The pond will be enlarged by excavating part of the flat area along the northern and eastern margins, and depositing the spoil material to lessen the sharp 10-foot high escarpment at the edge of the old quarried area. The new wetland areas will be shallower than the existing pond, which is nearly five feet deep, and it will be vegetated with native wetland plants to offer cover for resident amphibians and reptiles and invertebrates.

Finally, the now common invasive weeds scattered through the site, periwinkle and several more, will be removed. Eventually these species would overrun most of the rest of the site. Soon, instead, native plants will grow in their place. The dense native grasses will slow runoff, removal of the eucalyptus will reduce evapotranspiration, precipitation will fall and the water will remain longer on the site. Native small animals, adapted to this native plant community structure over thousands of years, are expected to increase in abundance and thrive.

The recovery will not be easy. A great deal of work will occur between the late summer of 2010 and the early spring of 2011. Monitoring of the restored site will continue for five years in grassland and wetland communities, and 10 years in wooded communities A considerable amount of site management is expected, especially removal and control of weeds as they attempt to re-establish. It is possible that some low-level management will always be necessary, given the proximity of the site to roads. However, once natural processes are once again allowed to function over the entire site instead of only parts of it, perhaps a tentative and partial equilibrium can be found.







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Updated: November 12, 2010

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