|Listed||February 25, 1994|
|Description||Unbranched plant growing to 16 ft (5m); with fleshy leaves and fragrant yellow flowers clustering in groups of three to eight.|
|Habitat||Lowland dry grassland and shrublands communities in the Na Pali Coast region.|
|Threats||Goats, insects, alien plants, fire, human impact, limited numbers.|
'Olulu (Brighamia insignis ) is an unbranched bellflower plant 3-16 ft (1-5 m) tall with a succulent stern that is bulbous at the bottom and tapers toward the top. The fleshy leaves, which measure 5-8 in (13-20 cm) long and 2.5-4.5 in (6-11 cm) wide, are arranged in a compact rosette at the top of the stem. Fragrant yellow flowers cluster in groups of 3-8 in the leaf axils (the point between the leaf and the stem), with each flower on a stalk 0.4-1.2 in (1-3 cm) long. The hypanthium (basal portion of the flower) has ten ribs and is topped with five oval or loosely triangular calyx lobes (partially fused sepals). The yellow petals are fused into a tube 2.8-5.5 in (7.1-14 cm) long, which flares into five elliptical lobes. The fruit is a capsule about 0.5 in (1.3 cm) long, containing numerous seeds.
Stream and wave action along the Na Pali Coast have cut deep valleys and eroded the northern coast to form precipitous cliffs as high as 3,000 ft (914 m). B. insignis grows predominantly on rocky ledges with little soil or steep sea cliffs in lowland dry grassland and shrubland from sea level to 1,300 ft (396 m) in elevation.
B. insignis had historical occurrences at the headland between Hoolulu and Waiahuakua Valleys along the Na Pali Coast on the island of Kauai and at Kaali Spring on the island of Niihau. The five extant populations grow on state and private land and total approximately 60-70 plants. Two populations are found along the Na Pali Coast, although approximately half of the individuals were destroyed in 1992 by Hurricane Iniki. These populations are within 0.4 mi (0.6 km) of each other within or on the boundary of the Hono Na Pali Natural Area Reserve. The most recent observations in 1994 estimated the population at Hoolulu to be 10-20 plants and the population at Waiahuakua to be 30-40 plants. There are also two populations in the Haupu Range within 2.7 mi (4.3 km) of each other. Hurricanes Iwa and Iniki destroyed 10 of the 12 individuals in the Haupu area. Only one plant survived in 1994 at both Mt. Haupu and Niumalu. The status of the small population on privately owned Niihau is not known, although there are reports that it was destroyed when the supporting cliff fell away.
Feral goats pose the major threat to B. insignis by causing defoliation and stem damage, restricting populations to inaccessible cliffs, and probably causing rock slides that degrade the plant's habitat. Alien plants pose another threat, especially introduced grasses such as molasses grass (Melinis minutiflora ), yellow foxtail (Setaria gracilis ), and smutgrass (Sporobolus indicus ), which prevent the establishment of seedlings. Other alien plants that potentially pose a threat are lantana (Lantana camara ), strawberry guava (Psidium cattleianum ), common guava (Psidium guajava ), and Java plum (Syzygium cumini ).
Hikers transport weed seeds, dislodge rocks and damage plants, to areas where B. insignis grows. Wildfire also poses a serious threat. Another problem is that some plants flower but fail to set seed, which may be due to a lack of pollinators or a reduction of genetic viability due to such few individuals. The carmine spider mite, an introduced insect, has been observed to cause leaf loss in both cultivated and wild individuals.
Conservation and Recovery
Current reproduction is not thought to be sufficient to sustain populations, with poor seedling establishment due to competition with alien grasses as the limiting factor. Pollination failure is common, and may be due to a lack of pollinators or a reduction in genetic variability due to the few remaining individuals. The flower structure appears to favor outcrossing. Some vegetative cloning has been observed and flower and leaf size appear to be dependent on moisture availability. Seeds of this species are undoubtedly dispersed by gravity. Although they may be blown for short distances, they are not obviously adapted for wind dispersal, being ovoid to ellipsoid, smooth, and lacking any sort of wing or outgrowth. B. insignis has been successfully propagated and then cultivated by Lyon Arboretum, National Tropical Botanical Garden, and Waimea Arboretum. The 1995 holdings at Lyon Arboretum consisted of two plants in the tissue culture lab, 10 plants in the greenhouse, and 18 plants in the nursery. In the same year, National Tropical Botanical Garden had both seeds in storage and plants growing in their garden, while Waimea Arboretum had 14 growing plants.
The Kauai District of Division of Forestry and Wildlife has outplanted 20 individuals of B. insignis at Kalepa and Nounou Forest Reserves.
Pacific Joint Venture
300 Ala Moana Blvd., Rm. 3-122
Honolulu, Hawaii 96850-0056
Telephone: (808) 541-2749
Fax: (808) 541-2756
U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Avenue
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
U.S. Fish and Wildlife Service. 25 February 1994. "Endangered and Threatened Wildlife and Plant; Determination of Endangered or Threatened Status for 24 Plants from the Island of Kauai, HI." Federal Register 59 (38): 9304-9329.