Kauai Hau Kuahiwi

Hibiscadelphus distans

Description

The Kauai hau kuahiwi is a small tree, growing up to 18 ft (5.5 m) tall. It has green, heart-shaped foliage densely covered with star-like hairs, smooth bark, and 1 in (2.5 cm) long, greenish-yellow flowers that turn a maroon color as they age.

Habitat

The natural habitat of the Kauai hau kuahiwi is open dryland forest on the island of Kauai.

Distribution

This species occurs on Kauai, which is the most northwestern (and geologically oldest) island in the Hawaiian archipelago.

Threats

The Kauai hau kuahiwi was only discovered and named by botanists in 1972. It was probably relatively widespread and abundant in the dryland forests of Kauai. Its natural habitat has, however, been severely reduced in area by agricultural development and other human activities. The Kauai hau kuahiwi is now a critically endangered species (as are other species of Hibiscadelphus and most other native plants of Hawaii).

The endangered Kauai hau kuahiwi is now confined in the wild to only 200 sq m, or 2,000 sq ft (0.02 hectare) of remnant habitat on a particular steep, rocky bluff in a canyon at an elevation of about 1,150 ft (350 m). In 1986, only 10 mature plants and some seedlings occurred at this single, wild site, located in a state-owned forest reserve. Such a small, isolated population is extremely vulnerable to extinction caused by a catastrophic disturbance. In addition, large herds of feral, non-native goats are maintained within the forest reserve as stock for hunting. These voracious herbivores browse within the canyon where the endangered Kauai hau kuahiwi survives, and they trample and eat seedlings of the rare plant and destroy other native vegetation. This also allows non-indigenous species of plants to penetrate the community, potentially leading to habitat changes that the Kauai hau kuahiwi will be unable to tolerate. In fact, non-native species of plants are already abundant within the single residual habitat of this critically endangered plant. The Kauai hau kuahiwi is also threatened by unauthorized collecting of specimens, vandalism, physical damages associated with hiking, and accidental wildfire.

Conservation and Recovery

The U. S. Fish and Wildlife Service is preparing a management plan that will increase protection for the critically endangered Kauai hau kuahiwi. Measures such as fencing of its small area of wild habitat have been contemplated, but may not be implemented because they could draw attention to the critical site, and perhaps attract collectors or vandals. Unrestricted hunting of goats would be useful; to deplete their populations and reduce their feeding pressure on the Kauai hau kuahiwi and other endangered species. Artificial propagation of the Kauai hau kuahiwi is being investigated, with the eventual goal of increasing its populations in the wild and in captivity.

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

Reference

U. S. Fish and Wildlife Service. 1996. "Recovery Plan for Hibiscadelphus distans." U. S. Fish and Wildlife Service, Portland, OR. 42 pp.