Schiedea kauaiensis

No Common Name

Description

Schiedea kauaiensis, a generally hairless and erect subshrub of the pink family, has stems that are normally 1-5 ft (0.3-1.5 m) long. The green, sometimes purple-tinged, leaves are opposite, narrowly egg shaped or lance shaped to narrowly or broadly elliptic, up to 5 in (12.7 cm) long, and 1.4 in (3.6 cm) wide. The petalless, perfect flowers are borne in open-branched inflorescences and moderately covered with fine, short, curly white hairs. The lance-shaped sepals, 0.08-1.5 in (.2-3.8 cm) long, are green or sometimes purple-tinged. The fruit is a capsule. The round to kidney-shaped seeds are about 0.08 in (2 mm) long. This species is distinguished from others in this endemic Hawaiian genus by its habit, its larger leaves, the hairiness of the inflorescence, the number of flowers in each inflorescence, the large size of the flowers, and the large seeds.

Fruit and flowers have been observed in July and August, and flowering material has been collected in September. There is no evidence of regeneration from seed under field conditions. Seedlings of species of Schiedea occurring in mesic or wet sites are apparently consumed by introduced slugs and snails. These have been observed feeding on S. membranacea, another mesic forest species that occurs on Kauai. In contrast to the mesic forest species, Schiedea that occur in dry areas produce abundant seedlings following winter rains, presumably because there are fewer alien consumers in the drier sites.

First collected near Papaa on Kauai by Otto Degener and Amy Greenwell in 1952, S. kauaiensis was described by in 1988. Stephen Weller, Ann Sakai, and Warren Wagner—the authorities on this endemic Hawaiian genus—accept S. kauaiensis as a distinct species. Other published names considered synonymous with S. kauaiensis include S. nuttallii var. paucifiora and S. wichmanii.

Habitat

S. kauaiensis typically grows in diverse mesic to wet forest on steep slopes. Associated plants include Psychotria hexandra (kopiko); Exocarpus luteolus (heau); lama; the federally threatened Peucedanum sandwicense (makou); and the federally endangered Euphorbia haeleeleana (akoko).

Distribution

S. kauaiensis had historical occurrences from Papaa to Mahanaloa on the northwestern side of Kauai. It was thought to be extinct until the two currently known populations of about 15 total plants were found on state land. The Mahanaloa Valley population occurs within Kuia Natural Area Reserve and the Kalalau Valley population within Na Pali Coast State Park.

Threats

Threats to S. kauaiensis include 1) habitat degradation and destruction caused by feral pigs, goats, and deer; 2) competition from several alien plant species; 3) predation by introduced slugs and snails; 4) landslides; and 5) a risk of extinction from naturally occurring events and reduced reproductive vigor due to the low number of individuals in only two known populations. S. kauaiensis is also potentially threatened by fire.

Conservation and Recovery

Since both populations of S. kauaiensis occur in state-managed areas, they are now protected by state and federal law.

Control of introduced snails and slugs is essential for protection of this species. S. kauaiensis reproduces prolifically under greenhouse conditions; therefore, the lack of seedlings in the field is almost certainly the result of the combined predations of snails, slugs, and hoofed mammals. Evidence for other species of Schiedea that occur in mesic areas suggests that these alien species consume essentially all seeds and probably a substantial portion of the seed crop.

Research on pollinators is necessary because of the possibility that declines in native pollinators might increase levels of inbreeding and result in depression.

Contacts

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/

Pacific Remote Islands Ecological Services Field Office
300 Ala Moana Blvd., Room 3-122
P. O. Box 50088
Honolulu, Hawaii 96850
Telephone: (808) 541-1201
Fax: (808) 541-1216

Reference

U. S. Fish and Wildlife Service. 1988. "Kauai II: Addendum to the Recovery Plan for the Kauai Plant Cluster." U. S. Fish and Wildlife Service, Portland, Oregon. 84+ pp.