San Clemente Island Bush-mallow

Malacothamnus clementinus

Description

San Clemente Island bush-mallow, Malacothamnus clementinus, is a rounded subshrub growing to about 3.3 ft (1 m) in height. It has numerous shaggy branches with many pink flowers formed in densely rounded (glomerate) masses, 4-8 in (10-20 cm) long.

This plant reproduces by sending out underground runners. Observations of this perennial in cultivation suggest that it may live about four to six years. When the parent plant dies, all connected plantlets die as well.

Habitat

Bush-mallow seems to grow in a wide range of soil types and is found on sparsely vegetated, inland rocky slopes. Cultivated plants grow well in sandy and clay soils in addition to rocky sites. This bush-mallow prefers full sun. The climate is maritime, with cool summers and mild winters and only a small range of seasonal temperature change. No temperatures below freezing (32°F; 0°C) have ever been recorded. The ease of resprouting from underground parts suggests that the species may be adapted to fire, like most other members of the mallow family.

Distribution

This shrub is a native of San Clemente Island, California, and was possibly distributed throughout the island.

The bush-mallow is now known from seven widely separated populations. For many years its only known locality was Lemon Tank, a reservoir located mid-island, where military dumping of scrap metal apparently prevented goats from destroying the plants. In 1977, a second colony was found in China Canyon and consists of two or three small plants on the edge of an almost inaccessible ledge. A native plant survey in 1985 located the additional populations, numbering several hundred individuals.

Threats

The decline of this species seems to be primarily the result of grazing and browsing by feral goats. A large population of goats nearly denuded the island of vegetation in the first part of the twentieth century. Goats have largely been eliminated from the island, but the damage caused to the fragile island ecology has been incalculable. Protection of existing plants requires maintaining fencing, erosion control, and further efforts to remove introduced feral animals.

Conservation and Recovery

Currently, plants of several colonies are in cultivation at the San Clemente Island Native Plant Nursery and at a mainland nursery site. A healthy stand grows within the Huntington Botanic Garden. Artificial cross-pollination in 1980 of plants from the Lemon Tank population and from China Canyon resulted in a successful seed set.

The island is administered by the U. S. Navy, which has cooperated with the U. S. Fish and Wildlife Service to design a management plan to conserve the island habitat and protect endemic plants, including the bush-mallow.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Ave.
Portland, Oregon 97232-4181
(503) 231-6121
http://pacific.fws.gov/

Natural Resources Office
Staff Civil Engineer (18N)
NAS North Island (Bldg 3)
San Diego, California 92135-5018

References

Power, ed., The California Islands: Proceedings of a Multi-Disciplinary Symposium. Santa Barbara Museum of Natural History, Santa Barbara.

Philbrick, R. N., and J. R. Haller. 1977. "The Southern California Islands." In M. Barbour and J. Major, eds., Terrestrial Vegetation of California. John Wiley and Sons, New York.

Raven, P. H. 1963. "A Flora of San Clemente Island, California." Aliso 5:289-397.

U. S. Fish and Wildlife Service. 1984. "Recovery Plan for the Endangered and Threatened Species of the California Channel Islands." U. S. Fish and Wildlife Service, Portland.