Haha (Cyanea koolauensis)
|Listed||October 10, 1996|
|Description||Leaves are linear to narrowly elliptic with a whitish underside.|
|Habitat||Slopes and ridge crests in wet 'ohi'a-uluhe forest or shrubland.|
|Threats||Predation by pigs and rats; competition from alien plants; military activities.|
Cyanea koolauensis is an unbranched shrub in the bellflower family with woody stems that grow 3.5-5 ft (106.7-152.4 cm) tall. The leaves are linear to narrowly elliptic with a whitish underside, 6.3-14.2 in (16.0-36.0 cm) long and 0.6-1.6 in (1.5-4.0 cm) wide. The leaf edges are hardened with shallow, ascending rounded teeth; leaf stalks are 0.6-1.8 in (1.5-4.6 cm) long. The flowering stalks, 0.6-1.6 in (1.5-4.0 cm) long, are three to six flowered. The hypanthium (basal portion of the flower) is 0.2-0.5 in (0.5-1.3 cm) long. The calyx lobes are fused into a sheath 0.08-0.3 in (2.0-7.6 mm) long. The dark magenta petals are 2.0-3.5 in (5.1-8.9 cm) long. The fruit is a round berry. C. koolauensis is distinguished from others in this endemic Hawaiian genus by the leaf shape and width, the whitish green lower leaf surface and, the lengths of the leaf stalks, calyx lobes, and hypanthium. C. koolauensis has been observed in flower and fruit during the months of May through August.
C. koolauensis was first described by Wilhelm Hillebrand in 1888 as Rollandia longiflora var. angus-tifolia from a specimen he collected on Oahu. Joseph Rock elevated the variety to full species status in 1918 as Rollandia angustifolia. In 1993, T. G. Lammers and others published the new name C. koolauensis to replace Rollandia angustifolia when they merged Cyanea and Rollandia, as the name Cyanea angustifolia had already been used.
C. koolauensis usually is found on slopes and ridge crests in wet 'ohi'a-uluhe forest or shrubland at elevations from 1,700-2,660 ft (518-811 m). Associated plant taxa include alani, Antidesma sp. (hame), Diplopterygium pinnatum, Psychotria sp. (kopiko), and Scaevola sp. (naupaka).
C. koolauensis was known historically from about 30 populations scattered throughout the Koolau Mountains on Oahu. In 1997, approximately 22 populations of less than 80 plants were known from the Walmea-Malaekahana Ridge to Hawaii Loa Ridge in the Koolau Mountains. These populations occur on City and County of Honolulu land, state land, and private land, including land leased to the Department of Defense for the Kahulm and Kawailoa Training Areas. Only two populations have as at least 10 individuals.
C. koolauensis is threatened by habitat destruction by feral pigs, potential impacts from military activities, potential predation by rats, competition with the aggressive alien plants Koster's curse and strawberry guava, trampling by hikers, overcollection, and risk of extinction from naturally occurring events or through reduced reproductive vigor due to the small number of remaining individuals.
C. koolauensis is potentially threatened by feral pig predation because the species is not known to be unpalatable to pigs, and they favor plants from the bellflower family for food.
It is possible that rats eat the fruit of C. koolauensis, a plant with fleshy stems and fruit that grows in areas where rats occur.
The noxious shrub Koster's curse is a threat to C. koolauensis, as are the dense stands of strawberry guava.
Overcollection for scientific or horticultural purposes and excessive visits by individuals interested in seeing rare plants in their natural settings could seriously damage C. koolauensis, whose populations are close to trails and roads, thus giving easy access to potential collectors.
Populations of C. koolauensis 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 drop-off and landing sites.
C. koolauensis has populations in recreational areas, near trails, and close to roads, making it very vulnerable to human disturbance.
Conservation and Recovery
Enclosures should be constructed around the known populations of C. koolauensis to reduce impacts from feral pigs. Subsequent control or removal of pigs from these areas will alleviate their impact on native ecosystems. Additionally, specific efforts should be made to immediately fence off and systematically weed within those populations at Kawailoa Training Area, Poamoho-Helemano Ridge, Hawaiiloa Ridge, and Halawa Ridge Trail that have only a few remaining individuals. In areas where fencing is not feasible, snaring as a means of ungulate control should be implemented. A commitment should be developed for long-term stew-ardship and conservation of these areas once they have been enclosed.
To prevent extinction of C. koolauensis, cultivated propagation should be initiated. Propagation material should be collected immediately from those populations mentioned above that have only have a few remaining individuals.
The threat of rat predation needs to be determined for C. koolauensis. If rats are deemed a significant threat, a management plan to control rats should be developed and implemented. This should include the use of the currently approved diphacinone bait blocks and ultimately a more broad-scale method such as aerial dispersal of rodenticide.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
U.S. Fish and Wildlife Service. 1998. "Recovery Plan for Oahu Plants." U.S. Fish and Wildlife Service, Portland.