'Akoko

Chamaesyce celastroides var. kaenana

Description

Chamaesyce celastroides var. kaenana is a low-growing shrub of the spurge family that can reach a height of 5 ft (1.5 m). The opposite and hairless leaves, up to 2.6 in (6.6 cm) long, are arranged in rows along the stem. The flower clusters appear on small side branches. The seed capsules contain small gray or white seeds. C. celastroides var. kaenana has been observed flowering and fruiting throughout the year, probably in response to precipitation. Fruits mature in groups of three to four, and plants live from five to 10 years.

This species has also been known as Euphorbia celastroides var. kaenana and E. celastroides var. niuensis; it is currently considered the same species as C. celastroides var. niuensis.

Habitat

C. celastroides var. kaenana is endemic to the Waianae Mountain Range at elevations of 30-700 ft (9.1-213.4 m). Associated vegetation includes mao (Gossypium tomentosum ), pauohiiaka (Jacquemontia ovalifolia ssp. sandwicensis ), sandalwood (Santalum freycinetianum ), and ilima (Sida fallax ).

Distribution

Historically, C. celastroides var. kaenana was known from the northwestern end of the Waianae Mountains and from one collection on the southeastern end of the Koolau Mountains. Extant populations now occur on federal land in the vicinity of Kaena Point and on state-owned land in Alau Gulch, Waianae Kal, and Keawaula; respective numbers of individuals at the first three locations in 1997 were 450, 12, and three. There are seven populations in Keawaula, three of which number fewer than three individuals each and four of which number 14-26 individuals. The 10 known populations, all located within an area of about 1 by 3 mi (1.6 by 4.8 km), contained approximately 545 plants in 1997.

Threats

The main threats to C. celastroides var. kaenana are competition from invasive alien plant species, fire, and the effects of recreational activity.

Koa haole, an aggressive tree that colonizes disturbed lowland shrub areas, directly threatens some populations. All dry shrubland species are at risk from fires that may be set accidentally in nearby recreational areas. In addition, hikers may trample plants inadvertently.

Conservation and Recovery

The Division of Forestry and Wildlife restricted off-road vehicle access to the Kaena Point National Area Reserve by constructing a large barrier on the Mokuleia side of the reserve. Access from the Waianae side is prevented by a natural washout. Three individuals were outplanted at the Kaena Point National Area Reserve in 1995; as of July 1997, only one survives. Other management activities in the reserve include (1) weeding of koa haole and kiawe in the vicinity of C. celastroides var. kaenana and (2) outplanting. This species is also being propagated at the National Tropical Botanical Garden.

Specific efforts should be made to immediately weed and protect populations that have only a few remaining individuals. A coordinated fire protection plan for endangered plants on state natural area reserves and federal lands needs to be developed and implemented.

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/

Pacific Remote Islands Ecological Services Field Office
300 Ala Moana Blvd., Room 3-122
P.O. Box 50088
Honolulu, Hawaii 96850
Telephone: (808) 541-1201
Fax: (808) 541-1216

References

Cuddihy, L. W., and C. P. Stone. 1990. Alternation of Native Hawaiian Vegetation: Effects of Humans, Their Activities and Introductions. Cooperative National Park Resources Study Unit, University of Hawaii Press, Honolulu.

Culliney, J. L. 1988. Islands in a Far Sea: Nature and Man in Hawaii. Sierra Club Books, San Francisco.

Stone, C. P., and J. M. Scott, eds. 1985. Hawaii's Terrestrial Ecosystems: Preservation and Management. Cooperative National Park Resources Study Unit, University of Hawaii Press, Honolulu.

Wagner, W. L., D. R. Herbst, and S. H. Sohmer. 1990. Manual of the Flowering Plants of Hawaii. University of Hawaii Press and Bishop Museum Press, Honolulu.