San Nicholas Island
Map SatelliteSan Nicolas Island, which is the most isolated of the Channel Islands, lies 98 kilometers (61 miles) from the nearest mainland point and 45 kilometers (28 miles) from its nearest neighbor, Santa Barbara Island. It is normally grouped with the southern islands.
The island's flora and fauna are highly depauperate. A total of 120 vascular plant species have been recorded as native to the island. The dominant vegetation is a coastal sage scrub which covers much of the island; there is some grassland and a small amount of a coastal strand community. Baccharis pilularis and Lupinus albifrons are dominant in the scrub; Abronia umbellata in the strand.
Two species are endemic to the island, Phacelia cinerea (Editor's note: this species now lumped with Phacelia distans) and Lycium verrucosum; however, as they have not been reported in 70 years, they are possibly extinct. The island shares two Channel Islands endemics with the northern islands, Astragalus traskiae and Malacothrix indecora, and three with the southern islands, Trifolium gracilentum var. palmeri, Lomatium insulare and Cryptantha traskiae. Additionally, five island endemics are found here and on other islands in the northern and southern groups, Lotus argophyllus ssp. argenteus, Artemisia nesiotica, Jepsonia malvifolia, Amsinckia spectabilis var. spectabilis, and Hemizonia clementina. (See Simi Hills - Santa Susana Pass re Hemizonia.) The flora exhibits relationships with mainland flora to the north; thus the Lomatium is closely related to the Lomatium parvifolium of coastal San Luis Obispo and Monterey Counties.
Terrestrial fauna is sparse and includes the locally rare California myotis, Myotis californicus, deer mouse, Peromysous maniculatus exterus, island fox, Urocyon littoralis dickeyi, and two reptiles, the side-blotched lizard, Uta stansburiana, and the island night lizard, Klauberina riversiana. (See also San Clemente Island.)
A number of sea birds breed here, including the tufted puffin, Lunda cirrhata, which is at the southern limit of its breeding range.
Six pinnipeds, the Steller sea lion, Eumetopias jubata, California sea lion, Zalophus californianus, Guadalupe fur seal, Arctocephalus philippi townsendi, harbor seal, Phoca vitulina, northern elephant seal, Mirounga angustirostris, and the northern fur seal, Callorhinus ursinus, utilize the island or occur in the vicinity. It supports a large rookery of Zalophus, with over 6,000 individuals present, as well as lesser numbers of Mirounga. The sea otter, Enhydra lutris, is occasionally observed in the offshore kelp beds. In the surrounding waters is one of the richest undisturbed vertebrate and invertebrate faunas in the State.
At the western end of the island are large dunes, 15 meters (50 feet) high and 480 meters (1,600 feet) long; at the eastern end a sand spit over 1.6 kilometers (1 mile) long and 5 meters (16 feet) high has been deposited by the wind. Scattered about the island are various caliche deposits. Over 14 marine terraces have been recorded; over 250 species of Pleistocene molluscs have been collected from 11 of the terraces, giving the most complete terrace sequence in Southern California. Short stretches of sandy beaches are separated by Eocene and Quaternary sandstone headlands.
Integrity: There is a Naval air strip with support facilities. Sheep and goats have destroyed much of the original shrubby vegetation.
Use: Restricted.
Ref: Philbrick, Ralph (ed.) 1967. Proceedings of the Symposium on the Biology of the California Islands, Santa Barbara Bot. Gar., Santa Barbara, 363 pp.
December 1976
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman
