Habitat surveys of the NASA-administered property conducted during fall 2010 identified eight natural terrestrial habitat types, two aquatic habitat types, and ruderal and developed areas (NASA, 2011). These habitat types are described briefly in the following text.
- Chaparral (172.6 acres)
Chaparral is the most abundant and widespread natural community at the site. This habitat covers 172.6 acres (approximately 38 percent) of the NASA-administered property. Characteristic species include chamise (Adenostoma fasciculatum), hoaryleaf ceanothus (Ceanothus crassifolius), black sage (Salvia mellifera), laurel sumac (Malosma laurina), thickleaf yerba santa (Eriodictyon crassifolium), Mendocino bushmallow (Malacothamnus fasciculatus), and chaparral yucca (Yucca whipplei). The abundance of these species is variable within this habitat type depending on soils, aspect, past disturbance, and other environmental factors.
- Sandstone Rock Outcrops (91 acres)
Approximately 91 acres (20 percent) of the NASA-administered property is composed of sandstone outcrops. In many areas, the outcrops are devoid of vegetation, while in other areas, the rocks are covered with a diverse assemblage of lichens. In some areas, scattered vascular plants are present. Common plants associated with these rock outcrops include bushy spikemoss (Selaginella bigelovii), lanceleaf liveforever (Dudleya lanceolata), chalk dudleya (Dudleya pulverulenta), cliffbrake (Pellaea spp.), orange bush monkey flower (Mimulus aurantiacus), and Santa Susana tarweed (Deinandra minthornii).
- Venturan Coastal Sage Scrub (64.4 acres)
Venturan coastal sage scrub covers 64.4 acres (approximately 15 percent) of the site. Characteristic species include coastal sagebrush (Artemisia californica), Eastern Mojave buckwheat (Eriogonum fasciculatum var. fasciculatum), black sage, chaparral yucca, thickleaf yerba santa, and common deerweed (Acmispon glaber).
- Developed (58 acres)
Developed areas include paved roads, parking areas, buildings, test structures, and other developments. Approximately 58 acres, or 13 percent, of the NASA-administered property have been developed.
- Non-native Grassland (19.2 acres)
Grassland habitat covers 19.2 acres (approximately 4 percent) of the site and often occurs in a mosaic with other habitat types. Most of the grasslands are characterized by slender oat (Avena barbata), intermixed with other introduced annual grasses such as ripgut brome (Bromus diandrus), soft brome (Bromus hordeaceus), and fescue (Vulpia spp). Native grasses including needlegrass (Nassella spp.), littleseed muhly (Muhlenbergia microsperma), and deergrass (Muhlenbergia rigens) are present in a few areas, but generally provide only minimal cover. Common herbaceous species include suncup (Camissonia spp.), winecup clarkia (Clarkia purpurea), longbeak stork’s bill (Erodium botrys), and winter vetch (Vicia villosa).
- Ruderal (17 acres)
Ruderal habitat is common around developed areas and areas that have been subject to human disturbance. Ruderal habitats cover approximately 17 acres (4 percent) of the site. Common species observed in these areas include telegraphweed (Heterotheca grandiflora), black mustard (Brassica nigra), Maltese star-thistle (Centaurea melitensis), silver bird's-foot trefoil (Acmispon argophyllus), stork’s bill (Erodium spp.), and common deerweed.
- Coast Live Oak Woodland (13.2 acres)
Coast live oak woodland is distributed widely across the site but only makes up 13.2 acres (approximately 3 percent) of the NASA-administered property. This habitat is characterized by mature coast live oak (Quercus agrifolia) trees. The understory generally consists of annual grasses such as ripgut brome and slender oat, with occasional native grasses including blue wildrye (Elymus glaucus) and California brome (Bromus carinatus). The understory shrub layer is poorly developed and, where present, generally consists of scattered Pacific poison oak (Toxicodendron diversilobum).
- Coast Live Oak Riparian Forest (9.2 acres)
Coast live oak riparian forest is found along the edges of the seasonal streams on the site. This habitat type covers 9.2 acres (approximately 2 percent) of the NASA-administered property. The composition of this community is generally similar to the coast live oak woodland habitat described previously, although the understory typically is more diverse in these areas and includes species such as Douglas’ sagewort (Artemisia douglasiana), creeping snowberry (Symphoricarpos mollis ), and American black elderberry (Sambucus nigra).
- Baccharis Scrub (2.6 acres)
Baccharis scrub is limited, covering only 2.6 total acres (less than 1 percent) of the site. This community is characterized by generally pure stands of coyotebrush (Baccharis pilularis). In these areas, coyotebrush ranges from dense cover with a sparse herbaceous layer to more open stands with an understory composed of annual grasses and scattered forbs.
- Mule-fat Scrub (2.1 acres)
Mule-fat scrub is limited, covering 2.1 acres (less than 1 percent) of the site. This habitat type is characterized by localized, dense stands of mule-fat (Baccharis salicifolia).
- Southern Willow Scrub (1 acres)
Southern willow scrub habitat on the NASA-administered property is characterized by arroyo willow (Salix lasiolepis) intermixed with occasional red willow (Salix laevigata) and narrowleaf willow (Salix exigua). This habitat type is uncommon on the site, covering only 1 acre (less than 1 percent). Southern willow scrub occurs in localized patches around scattered ponds and detention basins and along portions of the seasonal drainages within the site.
- Aquatic Habitats (0.2 acres)
Aquatic habitats identified on the NASA-administered property include 0.4 acre of open water and 0.2 acre of freshwater marsh habitat associated with various ponds and detention basins. Freshwater marsh is limited to the outer edges of ponds and detention basins and is characterized by southern cattail (Typha domingensis).