6. SITE-SPECIFIC CONDITIONS AND RECOMMENDATIONS

The following summary contains only information related to what makes an individual Natural Area worthy of management. This text has been created based on the detailed discussion presented within the individual sections (Sections 6.1 through 6.21). General issues and recommendations that apply to these Natural Areas are presented in Table ES-3.  Site-specific issues and recommendations are presented in Table ES-4.

One condition common to all the Natural Areas is the presence of numerous invasive species. High-priority pest plants include eucalyptus, iceplant (Carpobrotus edulis), poison hemlock (Conium maculatum), pampas grass (Cortaderia spp.), cape ivy, ehrharta grass (Ehrharta erectd), fennel (Foeniculum vulgare), French broom, English ivy, Bermuda buttercup (Oxalis pescaprae), wild radish (Raphanus sativus), Himalayan blackberry, and sheep sorrel (Rumex acetosella). The relative abundance and composition of these changes from Natural Area to Natural Area, but the presence of invasive exotic species is constant.  This issue is discussed in more detail in each of the respective text sections (Sections 6.1 through 6.21).

6.1  LAKE MERCED

Lake Merced, located in the southwest portion of the City, is the largest fresh-water lake in the City (Figure ES-1).  Lake Merced is comprised of four lakes: North, East, South, and Impound.  Although the open water of Lake Merced is the most striking feature, there are significant areas of native-dominated vegetation, especially bulrush marsh and willow scrub, two of the most important habitats for wildlife. Four locally sensitive plant species occur at Lake Merced: San Francisco wallflower (Erysimumfranciscanum), canyon live oak (Quercus agrifolia), San Francisco spineflower (Chorizanthe cuspidata ssp. cuspidata), and California pipe vine (Aristolochia californica).  Additionally, Lake Merced supports a small population of California red-legged frogs, western pond turtles (Clemmys marmorata) and sensitive bird species such as Double-crested cormorants (Phalacrocorax auritus) and common yellowthroats (Geothlypis trichas). The only sensitive invertebrate reported from Lake Merced is the Tomales isopod (Caecidotea tomalensis). (Top of Page)

6.2  MOUNT DAVIDSON

Mount Davidson, the tallest point in San Francisco, is located in south-central San Francisco just south of Portola Drive and partly adjacent to Juanita Avenue, Dalewood Way, and Molimo Drive in the Miraloma neighborhood (Figure ES-1). Mt. Davidson is mostly underlain by Franciscan chert with small areas of Franciscan greenstone. The lowest portion of the southern slope of the park is underlain by Franciscan greenstone.  The vegetation that characterizes Mt. Davidson are extensive areas of exotic forest and an open grassland with some native scrub vegetation on the eastern slope. Six sensitive plant species are reported from Mt. Davidson: San Francisco gumplant (Grindelia hirsutula var. maritima), San Francisco campion (Silene verecunda ssp verecunda), coast rock cress (Arabis blepharophylld), Pacific reed grass (Calamagrostis nutkaensis), broadleaf stonecrop (Sedum spathulifolium), and Johnny-jump-up (Viola pedunculatd). (Top of Page)

6.3 GLEN CANYON PARK AND O'SHAUGHNESSY HOLLOW

Glen Canyon Park and O'Shaughnessy Hollow are south of Twin Peaks in an area formally referred to as the San Miguel Hills (Figure ES-1). O'Shaughnessy Boulevard separates the Natural Areas with Glen Canyon Park to the east and O'Shaughnessy Hollow to the west. Most of Glen Canyon Park and O'Shaughnessy Hollow are underlain by Franciscan chert, large knobs of which can be found near the northwest and northeast rims of the canyon and along O'Shaughnessy Boulevard.  Islais Creek within Glen Canyon Park is one of the last free-flowing creeks in San Francisco. In Glen Canyon Park, forest, scrub, and grasslands are the dominant vegetation subformations.  The Natural Area at O'Shaughnessy Hollow is dominated by scrub, grasslands, and rock outcrops.

Seven species considered as sensitive for this project have been found in Glen Canyon or O'Shaughnessy Hollow:  San Francisco gumplant, Leaf daisy (Erigeron foliosus var. foliosus), Red columbine (Aquilegiaformosa), Pacific reed grass, Yellow-eyed grass (Sisyrinchium californicum), broadleaf stonecrop, and Johnny-jump-up.  The blue gum forest in Glen Canyon Park provides one of the few proven nesting locations of red-tailed hawks (Buteo jamaicensis) within the City of San Francisco. A population of San Francisco forktail damselfly (Ischnura gemind) is known from an asphalt channel along the northeastern edge of Glen Canyon Park. (Top of Page)

6.4  SHARP PARK

Sharp Park is located in the town of Pacifica in San Mateo County (Figure ES-1).  The park borders the Pacific Ocean and is bisected by Highway 1. This park is surrounded by significant open spaces. Mori Point borders the southwestern edge and the Sweeney Ridge Golden Gate National Recreation Area borders the park on the southeastern and eastern edges. The dominant vegetation at Sharp Park ranges from the exotic forests and native scrub of the upper canyon to the wetland and willow scrub vegetation associated with Sanchez Creek and Laguna Salada near the Pacific Ocean.  The wetland habitats of Sharp Park support several sensitive species including common yellowthroats, black-crowned night herons (Nycticorax nycticorax), California red-legged frog, San Francisco garter snakes (Thamnophis sirtalis elegans), Mission blue butterflies (Icarida icariodes missionensis), and San Francisco forktail damselfly. (Top of Page)

6.5   GRANDVIEW PARK, ROCK OUTCROP, GOLDEN GATE HEIGHTS, HAWK
HILL

Grandview Park, Rock Outcrop, Golden Gate Heights Park, and Hawk Hill all belong to a ridge-top sand dune system in the western portion of San Francisco, in the mid-Sunset or Sunset Heights area (Figure ES-1). Grandview Park is the northernmost park, located at 15^th Avenue and Moraga Street. Just south of Grandview Park is Rock Outcrop, located between 14^th Avenue and Funston Avenue.  Continuing to the south, Golden Gate Heights Park is located between Funston, 12^th, and 14^th Avenues. Hawk Hill, located at the intersection of Rivera Street and Funston Avenue, is the furthest south of this group. The soils at these Natural Areas are almost entirely Sirdak dune sand over Franciscan chert which is exposed at Rock Outcrop and Golden Gate Heights Park.  Most of the vegetation in these Natural Areas is classified as scrub and mosaic series with a smaller proportion being forest, rock outcrops, and grassland.  All of the forests mapped at these Natural Areas are limited to exotic cypress and eucalyptus. In all of these Natural Areas, grasses and shrubs are interspersed with open dune sands, a natural component of the plant community. Open sands are critical to early successional plant species such as wildflowers, forbs, and grasses.  Surveys conducted for this project located five species within these Natural Areas that are considered sensitive: dune tansy (Tanacetum camphoratum), and San Francisco wallflower, dune gilia (Gilia capitata ssp chamissonis), San Francisco campion, California croton (Croion californica).

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