Endangered Species in the Pacific Islands
Recovery Plan for the Schiedea adamantis
The endangered Schiedea adamantis was discovered in 1955 and is a branching, brittle shrub 11.8 to 31.5 inches (30-80 centimeters) tall. It is only found on the island of O‘ahu. It is also known as ma‘oli‘oli in Hawaiian and the Diamond Head Schiedea because of its locality.
As of 2010, only one population of 6 individuals exists today on the dry slopes of Diamond Head Crater in Honolulu. Current threats to the plant include fire, competition from alien plants, and disturbances by hikers. It has survived in the midst of this urban area largely because access is limited by proximity to Federal Aviation Administration facilities.
Schiedea adamantis -
Photo credit Dr. Lamoureux/University of Hawaii
Habitat & Distribution:
The current population is found in one of the few areas of Diamond Head Crater that is undisturbed by construction. Botanists have been unsuccessful in locating other possible Schiedea adamantis populations in Diamond Head. Given the extensive urbanization surrounding the crater, the dominance of alien vegetation, and the lack of similar remaining habitat elsewhere on southeast O‘ahu, it seems unlikely that other populations exist.
The known locality of S. adamantis can be roughly divided into three areas which differ in topography, density and sex ratios, and species composition. The top area includes about 36 feet (11 meters) across the rim of the crater where the plant first occurs and extends down the outside rim about 16.4 feet (five meters). This area is quite rocky and the dominant vegetation is S. adamantis.
The middle area includes the next 23 feet (7 meters) down the slope and is characterized by much higher density of alien koa haole (Leucaena leucocephala). The low area covers the next 32.8 feet (10 meters) and includes the S. adamantis furthest down the slope, and is very rocky with little soil development.
Because Schiedea adamantis is known only from one small population, any one of several threats could easily destroy the species: fire, alien vegetation, hiking trail at the top of the crater rim, lack of native pollinators, climate changes, and an insect called thrips.
S. adamantis was federally listed as endangered in February 1984. Research has shown that this plant can be grown from seeds or cuttings, although cuttings are difficult to establish. Numerous botnaical gardens have germinated seeds of this plant.