Lo'ulu

Pritchardia kaalae

Description

Pritchardia kaalae, a variety of lo'ulu and a member of the palm family (Arecaceae), is a single-stemmed palm up to 16 ft (5 m) in height. The waxy, hairless leaves are thin and papery or thick and leathery. Sometimes small points, dots, or linear and rusty scales are scattered on the lower leaf surface. The flowering stalks are composed of one or more branches. The round fruits are approximately 0.8 in (2 cm) in diameter. P. kaalae is distinguished from other members of the genus by the hairless or scaly leaves.

More than 75 years ago, a specimen was collected from a palm on Mt. Kaala that was later named P. kaalae in 1921. Edward Caum described P. kaalae var. minimain in 1930, which is not recognized in the current treatment of Hawaiian members of the family.

Habitat

P. kaalae is typically found on steep slopes and gulches in mesic forest or shrubland between elevations of 1,500-3,100 ft (457-945 m). Associated plant taxa include 'a'ali'i, kolea, ko'oko'olau, mamaki, na'ena'e, 'ohi'a, Eragrostis sp. (kawelu), and Tetraplasandra sp. ('ohe).

Distribution

P. kaalae was historically known from scattered populations in the central and north-central Waianae Mountains of Oahu. The five extant populations totaled about 130 individuals in 1997. There were several plants growing between the Waianae Kai-Haleauau summit divide and the Makua-Keaau Ridge at Manuwai Gulch, 51 plants at East Makaleha, 20 at Kaumokuni Gulch, three at Waianae Kai-Haleauau summit divide, and 53 at Makua-Keaau Ridge. These populations are located on state land, including Mt. Kaala National Area Reserve and land leased to the Department of Defense for Makua Military Reservation, and on federal land on Schofield Barracks Military Reservation. Three plants in the Palawai Gulch, discovered after P. kaalae was listed, were initially thought to be P. kaalae, but they are now thought to be distinct from other Pritchardia in Hawaii based on protein electrophoretic analysis.

Threats

Habitat degradation by feral pigs and goats; fruit predation by rats; potential impacts from military activities; incursions by the alien plants Christmas-berry, Maui pamakani, and prickly Florida blackberry; potential fire; and risk of extinction from naturally occurring events or through reduced reproductive vigor due to the small number of populations are all major threats to P. kaalae.

More than half of the individuals of this endangered species are directly threatened by feral goat trampling of plants and seedlings, as well as by goat-induced substrate erosion. P. kaalae is not known to be unpalatable to goats and grows in areas where they have been reported; direct predation is therefore a possible threat. Rat predation on fruits threatens the largest population of this species, as indicated by the lack of reproduction and seedlings for P. kaalae.

Christmasberry grows in dense thickets that threaten this listed plant. The mat-forming weed Maui pamakani and the noxious weed prickly Florida blackberry are both threats to P. kaalae.

Populations of P. kaalae that occur on land leased and owned by the U. S. Army face the threat of being damaged through military activity, either by troops in training maneuvers or by the construction, maintenance, and utilization of helicopter landing and drop-off sites.

Unintentionally ignited fires from ordnance training practices on military reservations also pose a potential threat to this species.

Conservation and Recovery

Four P. kaalae individuals propagated at the mid-level Nike site were outplanted in 1997. This species is being successfully propagated at the Lyon Arboretum, the National Tropical Botanical Garden, and the Waimea 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
(503) 231-6121
http://pacific.fws.gov/

Reference

U.S. Fish and Wildlife Service. 1998. "Recovery Plan for Oahu Plants." U.S. Fish and Wildlife Service, Portland, Oregon. 207 pp., plus appendices.