Hawaiian Vetch

Vicia menziesii

Description

Hawaiian vetch, Vicia menziesii, is a perennial, climbing vine with extensive lateral branching stems that have been reported to reach lengths of 66 ft (20 m). An individual plant can bear more than 200 flowers in 30-40 discrete flowerheads. The large flowers, which are pollinated by forest birds, open white, turning a conspicuous pink and rose color, then pale purple with age. Budding occurs May to August; fruiting occurs June through September. The vine typically climbs into the forest subcanopy. It is commonly known as Hawaiian wild broad-bean.

Habitat

Historic accounts place the species within the upper margins of the forests on the slopes of the Mauna Loa and Mauna Kea volcanoes, where there is a gradation from closed canopy rain forest to a more open montane forest. This narrow, transitional zone—called an ecotone—occurs between 4,780 and 6,500 ft (1,470 and 1,990 m) elevation. The vetch is found almost exclusively along the edges of montane forests dominated by koa (Acacia koa ) and ohia (Metrosideros collina ) trees.

Distribution

Hawaiian vetch grows on the eastern slopes of both Mauna Loa and Mauna Kea on the Island of Hawaii. Early specimens were collected along the Ainapo Trail from an area on southeast Mauna Loa known as Anipeahi.

This plant is known from the Keauhou-Kilauea area. In 1974, new colonies were discovered in a section of the Kilauea Forest on the northeastern slopes of Mauna Loa. A total of 706 plants in 114 colonies were surveyed in 1980. Intensive field work in 1984 discovered new colonies upslope from previously known sites, expanding the estimated population to roughly between 1,500 and 2,000 plants spread over an area of 3,950 acres (1,600 hectares).

Threats

Native Hawaiian forests have been severely degraded over the years by the activities of feral goats and pigs. These animals are capable of denuding large areas of native plants and disrupting the soil so that introduced weedy plants can invade the habitat. Introduced plants crowd out native plants, changing the forest composition. Forest birds that depend on native plants have suffered severe population declines, depriving the Hawaiian vetch of its chief agents of pollination.

Logging has also been a factor in disrupting the native forests. Sites have often been clear-cut, then converted to cattle pasture. Plants grow adjacent to commercial ranching operations at several locations.

Conservation and Recovery

The primary objective for recovering the Hawaiian vetch is to secure conservation agreements with landowners to protect remaining habitat in the Keauhou and Kilauea forests, and within the Kulani Prison Farm. Protection can best be achieved by fencing habitat areas and by promoting hunting of feral animals.

The Recovery Plan recommends purchasing land that meets essential habitat requirements; rehabilitating the existing habitat through the removal of exotic vegetation and feral animals; establishing cultivated propagation programs; and studying the effects of logging, grazing, and predation by insects and rodents.

Contacts

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232
http://pacific.fws.gov/

Pacific Remote Islands Ecological Services Field Office
P.O. Box 50088
Honolulu, Hawaii 96850-5000
Telephone: (808) 541-1201
Fax: (808) 541-1216

References

Lassetter, J. S., and C. R. Gunn. 1979. "Vicia menziesii Sprengel (Fabaceae) Rediscovered: Its Taxonomic Relationships." Pacific Science 33(1):85-101.

Menzies, A. 1920. Hawaii Nei, 128 Years Ago. W. F. Wilson, ed. Privately published, Honolulu.

U.S. Fish and Wildlife Service. 1984. "The Vicia menziesii Recovery Plan." U.S. Fish and Wildlife Service, Portland.