Tetramolopium filiforme

No Common Name

Description

Tetramolopium filiforme is a branched dwarf shrub of the aster family that grows 2-6 in (5-15 cm) high. The leaves, bunched at the tops of the stems, are narrowly linear and untoothed. The flower heads occur either singly or in clusters of two to four. Each head has 35-52 white to pale lavender ray florets and 18-30 maroon or occasionally yellow disk florets. The ray florets are female flowers; the disk florets function as male flowers. Some plants of the species have wider, toothed leaves and have been given the varietal status of T. filiforme var. polyphyllum. Both varieties have endangered status.

Cultivated T. filiforme germinates in about three weeks. The plants are approximately 3.5 in (8.9 cm) high when they produce their first buds 15 weeks after germination; the first blossoms usually appear three weeks later. During growth an inflorescence forms at the apex of each shoot while new shoots develop laterally.

T. filiforme, a relatively short-lived plant, usually survives less than five years. The species usually flowers in the wild in the late winter or spring, although flowering can also be induced by heavy rainfall.

Habitat

T. filiforme grows on dry cliff faces and ridges at elevations between 1,100 and 3,000 ft (335.3 and 914.4 m). Associated species include 'a'ali'i, ahinahina, and Schiedea manii.

Distribution

Historically, T. filiforme was known from Ohikilolo Ridge, Keaau Valley, and Makaha Valley in the northern Waianae Mountains. The five current populations, distributed over an area of about 2 by 5 mi (3.2 by 8 km), contained an estimated 1,550 individuals in 1997, the vast majority of them on federal land. Twenty-five plants at Keaau Valley, 20 at Kahanahaiki Valley, about 1,500 at Makua-Keaau Ridge, and several at Lualualei all occur on federal land. Two plants remain on state land at Puu Kawiwi and on City and County of Honolulu land at Waianae Kal.

Threats

The main threats to T. filiforme are habitat degradation by feral goats and competition from aggressive alien plant species. Feral goats, which are managed by the state as game animals, have been on the island for 170 years. Because of their agility they are able to reach relatively inaccessible cliff areas. The disturbance of steep slopes promotes erosion which leads to a loss of plant life.

T. filiforme, like most rare Hawaiian plant species, is threatened by several alien plants. Christmas-berry forms dense thickets and may also release chemicals that inhibit the growth of other species. Firetree, planted in the Waianae Mountains during a reforestation project, forms a dense closed canopy that excludes other species and produces its own nitrogen, enabling it to colonize areas to which native species have become adapted. Molasses grass grows in dense mats that smother native vegetation. Molasses grass is also fire-adapted and provides fuel for spreading wildfires.

Such wildfires are a threat to T. filiforme populations that lie near the U.S. Army's Makua Military Reservation and Schofield Barracks. Within a 14-month period from 1989 to 1990, ten fires resulted from weapons practice on the reservation. In order to minimize damage from fires, the army has constructed firebreaks between the target areas and the surrounding forest.

Conservation and Recovery

The army has adopted a fire management plan that includes realigning targets and establishing firebreaks. This may aid in protecting this species from the threat of fire. The completion of the boundary fence on the south and southeast perimeter of Makua Valley and continued goat control efforts, though limited, should help to protect the remaining population at Makua Military Reservation from further goat-induced habitat degradation. This species has been propagated at the National Tropical Botanical Garden.

Enclosures or strategic barrier fences should be constructed around the known populations of this species to reduce impacts from feral goats. Subsequent control or removal of goats from these areas will alleviate their impact on native ecosystems. Specific efforts should be made to immediately fence and protect the Pun Kawiwi population and other occurrence that have only a few remaining individuals.

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
Telephone: (503) 231-6121
http://pacific.fws.gov/

U.S. Fish and Wildlife Service
300 Ala Moana Boulevard, Room 6307
P.O. Box 50167
Honolulu, Hawaii 96850

References

Cuddihy, L.W., and C.P. Stone. 1990. Alteration 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.