Endangered Species in the Pacific Islands
Recovery Plan for Hawaiian Gardenia
The Hawaiian gardenia (Gardenia brighamii ), also known as Nanu in Hawaiian, is found only in the Hawaiian Islands. It is a small tree up to 20 feet (6.096 meters) in height, with trunks up to 12 inches (30.48 centimeters) in diameter and somewhat smooth. The tree has white flowers that are very fragrant.
Only a dozen individuals are known on the islands of O‘ahu and Lana‘i. It was once found on Maui, Moloka‘i, and the island of Hawai‘i but is believed to be gone from those 3 islands now.
All but one of the trees on Hawai‘i were destroyed by a road repair crew in 1930; the remaining one survived in the wild at least until 1955, when it was collected by naturalist J.F. Rock. The location and status of this tree is unknown. Only one tree was reported on Maui at the head of Olowalu Valley but is believed to be gone today.
Hawaiian gardenia -
Photo credit Dr. Lamoureux/University of Hawai‘i
Habitat & Distribution:
The Hawaiian gardenia is found in dry shrub and forests on the islands of Moloka‘i, O‘ahu, and Lana‘i. Sites are generally located at low to mid-elevation (1,000 to 1,800 feet; 304.8 to 548.6 meters) with well-drained, lateritic soils with few nutrients. All populations of this tree are threatened by alien plant competitors, introduced herbivores, fire, and pathogens.
At present, a total of 12 Hawaiian gardenia trees remain in the wild, all on private property.
Lowland forests have been extensively cleared for agricultural and urban uses, subjected to intentional and unintentional fires, heavily grazed by cattle, goats, pigs, axis deer and Mouflon sheep, and infested with alien weeds and pathogens. These impacts have reduced the dry leeward (southwest) forests to scattering of individual native plants surrounded by a sea of alien weeds or, at best, small fragmented pockets of remnant vegetation.
The Hawaiian gardenia was federally listed as an endangered species in 1985. Numerous botanical gardens and rare plant facilities collect and propagate seed from the Hawaiian gardenia and other rare plants. These efforts have resulted in the successful cultivation of seeds from O‘ahu sites and from one of the Lana‘i
Castle and Cooke, Inc., landowners of the island of Lana‘i, provided major funding to fence three of these endangered trees at Kanepu‘u on land that is now part of the Lana‘i Watershed Partnership.
Starting in the 1970s, a number of volunteers and organizations, including the Hui Malama Pono o Lana‘i, erected and maintained protective fences around the Kanepu‘u plants. Private individuals are known to have some endangered gardenias in their gardens. It is possible that these private gardens contain wild-collected genotypes not represented in the botanical gardens. If this is so, then these collections may be of great value.