Gouania Hillebrandii

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Gouania hillebrandii

No Common Name

Status	Endangered
Listed	November 9, 1984
Family	Rhamnaceae (Buckthorn)
Description	Shrub with white flowers and downy branches.
Habitat	West Maui; dry gulches and ridges.
Threats	Livestock grazing, feral animals, insect infestation.
Range	Hawaii

Description

Gouania hillebrandii is a bushy shrub that ranges from 0.5-6 ft (15-183 cm) tall. Smaller shrubs have simple or sparingly branched stems; branching increases with height. The slender, woody stems are covered with ash or rust-colored fuzz. Leaves are oval, up to 3 in (7.6 cm) long. Small, white flowers are borne in clusters of five. Seeds resemble tiny, brown beans.

Habitat

This shrub is known from the dry gulches and ridges of western Maui, occurring mostly on slopes with a western exposure. The higher elevation climate is arid and harsh. Rugged, volcanic ridges support a sparse vegetation that is adapted to almost constant winds. High winds and high levels of solar energy discourage many introduced plants, minimizing competition in the habitat.

Distribution

First collected in 1870, it is believed that G. hillebrandii is endemic to West Maui. Records indicating populations on East Maui are considered in error. The plant is known from two localities on the island of Maui: from the slopes of Paupau (above the community of Lahaina), and from Lihau Mountain. From the mid-1970s to the mid-1980s, plants on the lower slopes near Lahaina have decreased from an estimated 300-30 plants, mostly because of the effects of grazing animals. Numbers are considered very low.

Threats

Grazing and trampling by livestock and feral animals has severely reduced populations of G. hillebrandii on Maui. The state of Hawaii has volunteered to withdraw cattle grazing permits for the entire Lahaina area where the plants are found and to fence portions of the habitat. While agricultural pressures in the Lihau area have relaxed somewhat, cattle grazing continues on several tracts of marginal land, denuding vegetation and promoting erosion. Feral animals, particularly goats, remain a problem. An imported insect, the hibiscus snow scale (Pinnaspis strachani ), has spread on the island since the early 1940s and has damaged or destroyed many native plants.

Conservation and Recovery

Critical Habitat for this species has been designated for four areas on the island of Maui. This designation includes 52 acres (21 hectares) encompassing three ridges forming the south wall of Kanaha Stream Valley, and three areas of 20 acres (8.1 hectares) each on the west flank of Lihau Mountain. In addition to these habitat designations, it is necessary to reduce the threats posed to the rare plant by browsing and trampling by cattle, competition with alien plants, defoliation by introduced insects, and wildfire. The known populations of the G. hillebrandii should be monitored, and research undertaken into its biology and habitat needs. It should be cultivated in captivity, and seedlings out-planted to supplement the small wild population.

Contact

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