Anacapa Island

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Essentially a slender chain of islands about 8 kilometers (5 miles) long and 0.8 kilometer (0.5 mile) wide, Anacapa is the closest to the mainland and the smallest of the Channel Islands. Floristically it is also one of the most depauperate of the islands, with but 70 species recorded. Sixteen island endemics are present but none occurs exclusively on Anacapa. Approximately 90% of the island is in coastal sage scrub, though there are Southern oak woodland species in the drainage patterns. (There is no permanent freshwater source on the island.)

Zoologically it is important as the only known breeding site in the State of the brown pelican, Pelecanus occidentalis californicus. This species in the past decade has suffered reproductive failures due to exceptionally thin egg shells, apparently caused by DDT and its metabolites. In recent years breeding successes have been increasing but the species is still endangered. Other sea birds nest on the island, and the California sea lion, Zalophus californianus, is a frequent visitor.

The marine communities are particularly rich, as the island is in the Santa Barbara gyre and receives cold water from the California Current from the north and warm water from the south. Elements of both northern and southern marine floras and faunas are present.

This island, as well as the other northern islands, is related geologically to the Santa Monica Mountains on the mainland. A granitic core intruded into what are now slates and schists which, in turn, are overlain by Cretaceous and Cenozoic sedimentary and volcanic rocks. Anacapa has been connected with the mainland several times, the latest during the late Pleistocene.

At the eastern end there is a sea arch formed by wave action. There are several marine terraces evident, one at approximately 10 meters (30 feet), another at 75 meters (250 feet), which exhibit fossil marine mollusc beds.

Integrity: As the rugged, rocky coastline offers few easy landings the island is virtually untouched, save for an abandoned lighthouse and related structures on the eastern end. The western islet is closed to visitors during the sea bird nesting season.

Use: Research, educational, observational.

Ref: Lipps, J. H. 1964. Late Pleistocene History of West Anacapa Island, California. Bull. Geol. Soc. of Amer. No. .75, pp. 1169-1176.

Philbrick, Ralph N. (ed.), 1967. Proceedings of the Symposium on the Biology of the California Islands. Santa Barbara Botanic Garden, Santa Barbara. 363 pp.

Send mail to naturebase@aol.com with questions or comments about this web site. Last modified: December 06, 2005

Send mail to naturebase@aol.com with questions or comments about this web site.
Last modified: December 06, 2005