Gouania meyenii

No Common Name

Description

Gouania meyenii is a shrub of the buckthorn family that grows to a height of 7 ft (2.1 m). The oval leaves are untoothed, 1.2-2.8 in (3-7.1 cm) long, and papery in texture. Small white flowers appear in clusters arising from the leaf axils; the smooth fruits are winged. This species flowers from March to May, and seed capsules develop in six to eight weeks. Plants appear to live 10-18 years in the wild. G. meyenii has also been known as G. integrifolia, G. orbicularis, G. oliveri, and G. gagnei. G. meyenii is one of three species of Gouania that have been known from Hawaii. G. hillebrandi, which is found on Maui, was listed as endangered in 1984. G. vitifolia has only been collected seven times; in 1932 it was believed to be on the verge of extinction. The only known population is in the Waianae Mountains.

Habitat

G. meyenii typically grows on rocky ledges, cliff faces, and ridge tops in dry shrubland or o'hi'a lowland mesic forest at an elevation of 1,900-2,700 ft (579.1-823 m). Associated plants include aalii, akoko, kopiko, manono, alani, olopua, kookoolau, Carex meyenii, lama, kolokolo kuahiwi, and Senna gaudichaudii (kolomona).

Distribution

Historically, G. meyenii was known on Oahu from central and southern areas of the Waianae Mountains, from Kamaileunu Ridge to Honouliuli. This species was also recorded from Diamond Head in 1831. This species is currently found on Oahu in an area about 1 mi (1.6 km) square at Kamaileunu Ridge and Makaha-Waianae Kai Ridge on state and city/county land. This species was recently discovered on Kauai at two locations within the Na-Pali Kona Forest Reserve in the Kalalau Valley and at one location in Koaie Canyon in the Hipalau Valley. The four populations on Oahu contained an estimated 83 individuals in 1997; the three populations on Kauai, within approximately 4 mi (6.4 km) of each other, contained an estimated nine plants. The total population on both islands was therefore an estimated 92 individuals in seven occurrences.

Threats

The main threat to G. meyenii is competition from alien plant species. Christmasberry, an aggressive tree introduced to Hawaii before 1911, forms dense thickets and may also release chemicals that inhibit the growth of other species. Strawberry guava is an invasive tree that forms dense stands that exclude other species. Molasses grass grows in dense mats that smother native vegetation. It is also fire adapted and provides a fuel for spreading wild-fires. G. meyenii populations lie near the U.S.

Army's Makua Military Reservation and Schofield Barracks. Within a 14-month period from 1989 to 1990, 10 fires resulted from weapons practice on the reservation. In order to minimize fire damage, the army has constructed firebreaks between the target areas and the surrounding forest. With a total known species population of less than 100 plants in a very limited range, G. meyenii is also vulnerable to extinction through unpredictable human or natural events.

Conservation and Recovery

This species is being propagated at the National Tropical Botanical Garden and the Lyon Arboretum.

Contact

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

Reference

U.S. Fish and Wildlife Service. 12 July 1993. "Endangered and Threatened Wildlife and Plants; Endangered or Threatened Status for Five Florida Plants." Federal Register 58(131):37432-37443.