Purisima Point Dune Area
Map SatelliteSeveral plant communities are found within this area, though most of it is covered by coastal sage scrub with Artemisia californica, Salvia mellifera, Mimulus aurantiacus (= Diplacus lompocensis) and Eriogonum parvifolium the dominants. This community makes a gradual transition to the coastal strand community. In the transition zone are such species as Lupinus chamissonis, Erysimum insulare ssp. suffrutescens, the rare Erysimum capitatum var. lompocense, and Ericameria ericoides; the last two species also occur in the scrub proper.
Due to the width of the dunes, the coastal strand is well developed in the area and includes, among others, Abronia maritima, Abronia latifolia, Abronia umbellata, Cakile maritima, Convolvulus soldanella and Ambrosia chamissonis. The rare Senecio blochmaniae, Cirsium rhothophilum, Scrophularia atrata and Castilleja mollis occur here.
Cutting through the area is the San Antonio Creek which, in the dunes by the ocean, forms a small lagoon. This is sometimes open to the sea but normally is closed. There is a small freshwater marsh here, but east of the dunes the basin widens considerably and there is a good riparian association as well as several marshes. Approximately 4 kilometers (2.5 miles) inland the creek widens and forms Barka Slough, an extensive freshwater marsh with the rare Cirsium loncholepis in the vicinity. Some 25 plant species occur in the marsh, including the bulrushes Scirpus americanus, Scirpus californicus and Scirpus robustus, the cattails, Typha angustifolia and Typha latifolia, among others. The riparian vegetation includes, among the dominants, box elder, Acer negundo, black cottonwood, Populus trichocarpa, and Salix lasiandra.
On the San Antonio terrace there are a number of depressions in the dunes that vary from moist to year-round ponds which support freshwater marsh vegetation; some support a riparian woodland or even small patches of coast live oak, Quercus agrifolia.
Animal life is abundant, with a wide variety present. Of note is the legless lizard, Anniella pulchra, and possibly the endangered unarmored three-spined stickleback, Gasterosteus aculeatus williamsoni. If the latter identification is correct, the population will be a disjunct from the Los Angeles Basin.
The dunes extend from some 13 kilometers (8 miles) along the coast and are of Recent and Pleistocene origin, resting on terraces of the Pleistocene Orcutt formation. The dune layer is rather thin, with a local relief seldom exceeding 15 meters (50 feet). Both parabolic and transverse dunes are found here, and there are active foredunes.
Integrity: There are roads and a railroad in the area but most of the area is virtually undisturbed. See Santa Ynez Lagoon.
Use: Restricted. There is public access for fishing along the beach for a distance of 5.5 kilometers (3.5 miles) north of the Santa Ynez River mouth; however, the remainder is closed.
Ref: Coulombe, H. and C. F. Cooper, 1975. Ecological Assessment of Vandenberg Air Force Base, Calif. Vol. I and II, Air Force Civil Eng. Cent. Tyndall Air Force Base, Florida, 189 pp. and 201 pp.
Cooper, W. S., 1967. Coastal Dunes of California. Geo. Soc. Amer. Mem. #104, pp. 89-91.
March 1977
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman
