National Collection of Imperiled Plants

CPC National Collection Plant Profile

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D. Ragone

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CPC National Collection Plant Profile

Wilkesia hobdyi

Family:	Asteraceae
Common Name:	dwarf liau
Author:	St. John
Growth Habit:	Shrub
CPC Number:	4421

Distribution
Protection
Conservation
References

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Photographer: D. Ragone

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Photographer: S. Perlman

Wilkesia hobdyi is Fully Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

National Tropical Botanical Garden

Wilkesia hobdyi

The genus Wilkesia (Asteraceae) contains two species endemic to Kaua�i. One of these, Wilkesia hobdyi, is threatened. This plant is currently found only on nearly vertical rock outcrops in western Kaua�i, and is threatened by the actions of feral goats.

Goats were brought to the islands of Hawaii by Europeans as a food source in the late 1700�s, and quickly spread throughout even the most remote areas of the islands. Goats caused extensive damage to Hawaiian plant species, as they evolved in the absence of grazing mammals and therefore had no defense mechanisms to limit the detrimental effects of browsing. Since then, feral goats have reduced or eliminated whole populations of native plants, leaving remnant plant populations behind only on the steepest and most inaccessible cliffs, where even the sure-footed goat doesn�t venture. Such is the fate of this species, the dwarf iliau.

This small member of the sunflower family (Asteraceae) is a short-lived perennial shrub, which branches from the base and can grow up to 60 centimeters tall. The tip of each branch bears a cluster of narrow leaves (about 7.5 to 15 centimeters long) growing in whorls joined together into a short sheathing section at their bases. The cream-colored flower heads grow in clusters that are about 2 centimeters in diameter (USFWS 1995). Flowering plants have been observed in June, September, October, and December (Wagner et al. 1999).

Distribution & Occurrence

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State Range

Hawaii

Habitat

W. hobdyi grows on coastal dry cliffs or very dry ridges from 275 to 400 meters (900 to 1,310 ft) elevation (USFWS 2000).

Associated species of W. hobdyi include Artemisia sp. (sagebrush), W. gymnoxiphium (iliau), Lipochaeta connata (nehe), Lobelia niihauensis (no common name [NCN]), Peucedanum sandwicense (makou), Hibiscus kokio subsp. saint johnianus (kokio), Canthium odoratum (alahee), Peperomia sp. (ala ala wai nui), Myoporum sandwicense (naio), Sida fallax (ilima), Waltheria indica (uhaloa), Dodonaea viscosa (aalii), and Eragrostis variabilis (kawelu).

Distribution

W. hobdyi, an endemic to Kaua�i, was first collected in 1968 on Polihale Ridge, and was not formally described until 1971. W. hobdyi occurs on State and privately owned lands and may occur on or near Federal, or land under Federal jurisdiction on Makaha Ridge, and in Koke'e State Park (USFWS 1995).

There are populations in the Puu Ka Pele Forest Reserve, growing on the north-facing, nearly vertical rock outcrops near the summits of the adjacent Polihale and Kaaweiki ridges. There are also plants growing on a cliff face in Waiahuakua Valley, on the boundary between the Hono O Na Pali NAR (Natural Area Reserve) and the Na Pali Coast State Park, approximately 16 kilometers (10 miles) northeast of the other populations (USFWS 2002).

Number Left

Number of Populations: 5 (USFWS 2001)
Number of Plants: <300 (USFWS 2001)

Protection

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Global Rank:	G1	5/15/1997	Guide to Global Ranks
Federal Status:	LE	6/22/1992	Guide to Federal Status
Recovery Plan:	Yes	9/20/1995

State/Area Protection

	State/Area	Rank	Status	Date

Conservation, Ecology & Research

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Ecological Relationships

W. hobdyi is probably pollinated by insects and is probably self-incompatible. Flowering was observed most often in the winter months, but also during June. Fruits may be dispersed when they stick to the feathers of birds. Hybridization with W. gymnoxiphium may be occurring. (Sakai et al. 1995)

Threats

Threats to W. hobdyi include habitat disturbance and browsing by feral goats. Although the low number of individuals and their restricted habitat could be considered a potential threat to the survival to the species, the plant appears to have vigorous reproduction and may survive indefinitely if goats are eliminated from its habitat. Fire and extinction through naturally occurring events, such as landslides or hurricanes, could also be threats to the survival of the species (USFWS 2000). The impact of hybridization is unknown.

Current Research Summary

Essential habitat areas for all listed, proposed, and candidate plants and evaluated species of concern were identified to determine if essential habitat areas would provide for their habitat needs (USFWS 2002).

The seeds of W. hobdyi have been tested at the National Tropical Botanical Garden (NTBG) finding that they are orthodox and can tolerate freezing. The laboratory germination time was 2 months (Yoshinaga 2002).

Current Management Summary

A recovery goal stated for W. hobdyi included the establishment of eight to ten populations with a minimum of 300 individuals per population on Kaua'i (USFWS 2002).

The National Tropical Botanical Garden (NTBG) currently has ex situ holdings of 1,480 seeds in its seed bank, which represents four out of the five populations. In addition, there is one plant growing in the nursery and 14 individuals representing two out of the five populations growing in the grounds of the botanical garden.

Research Management Needs

1. Pollination biology and seed dispersal mechanism studies need to be done.
2. Map genetic diversity in the surviving populations of W. hobdyi.
3. Test the influence of weeding and fencing on populations of W. hobdyi.
Recommendations derived from M.H. Chapin and M. Maunder.

Ex Situ Needs

1. Establish secure ex situ stocks with full founder representation.
2. Develop proper horticultural protocols and pest management for W. hobdyi.
3. Survey ex situ holdings and conduct molecular fingerprinting.
Recommendations derived from M.H. Chapin and M. Maunder.

References

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Books (Single Authors)

Wagner, W.L.; Bruegmann, M.M.; Herbst, D.R; Lau, J.Q.C. 1999. Hawaiian Vascular Plants at Risk: 1999. Honolulu, HI: Bishop Museum Press Honolulu.

Wagner, W.L.; Herbst, D.R.; Sohmer, S.H. 1999. Manual of the flowering plants of Hawai'i--Revised Edition. Honolulu, HI: University of Hawaii Press and Bishop Museum Press. 1853p.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Electronic Sources

NatureServe. (2008). NatureServe Explorer: An online encyclopedia of life [web application]. [Internet].Version 7.0. NatureServe, Arlington, Virginia. http://www.natureserve.org/explorer. Accessed: (June 17, 2008).

USFWS. (2001). Unpublished data. U.S. Fish and Wildlife Service, Honolulu, Hawaii 96817. Accessed: 2001.

Yoshinaga, A. (2002). Seed storage characteristics of Hawaiian species. [Web site] University of Hawaii, Honolulu, Hawaii 96848. http://www.hawaii.edu/scb/seed/seedtabl.html. Accessed: 2002.

Journal Articles

Baldwin, B.G.; Kyhos, D.W.; Dvorak, J. 1990. Chloroplast DNA evolution and adaptive radiation in the Hawaiian silversword alliance (Asteraceae--Madiinae). Annals of the Missouri Botanical Garden. 77, 1: 96-109.

Bohm, B.A.; Fong, C. 1990. Nonpolar Flavonoids of Wilkesia and Argyroxiphium. Phytochemistry (Oxford). 29, 4: 1175-1178.

Carlquist, Sherwin. 1998. Wood anatomy of Wilkesia (Asteraceae) with relation to systematics, organography, and habit. Journal of the Torrey Botanical Society. 125, 4: 261-267.

Carr, G.D. 1985. Monograph of the Hawaiian Madiinae (Asteraceae): Argyroxiphium, Dubautia, and Wilkesia. Allertonia. 4: 1-123.

Carr, G.D. 1988. Abstract: Biological diversity of the hawaiian Tarweeds. American Journal of Botany. 75, 6 part 2: 152.

Sakai, A.K.; Wagner, W.L.; Ferguson, D.M.; Herbst, D.R. 1995. Origins of Dioecy in the Hawaiian Flora. Ecology. 76, 8: 2517-2529.

St. John, H. 1971. The status of the genus Wilkesia (Compositae), and discovery of a second Hawaiian species. Hawaiian plant studies 34. Occasional Papers of the Bernice P. Bishop Museum. 24, 8: 127-137.

USFWS. 1976. Proposed Endangered Status for 1700 U.S. Plants. Federal Register. 41: 24523-24572.

USFWS. 1981. New Document Presents Assessment of Native Plant Vulnerability. Endangered Species Technical Bulletin. 6, 1: 1, 4-5.

USFWS. 1989. Proposed endangered status for the plant, Wilkesia hobdyi (dwarf illiau). Federal Register. 54, 189: 40444-40447.

USFWS. 1992. Determination of endangered status for Wilkesia hobdyi. Federal Register. 57, 120: 27859-27862.

USFWS. 2000. Determinations of Whether Designation of Critical Habitat is Prudent for 81 Plants and Proposed Designations for 76 Plants From the Islands of Kauai and Niihau, Hawaii; [Proposed Rule]. Federal Register. 65, 216: 66807-66885.

USFWS. 2002. Revised Determinations of Prudency and Proposed Designations of Critical Habitat for Plant Species from the Islands of Kauai and Niihau, Hawaii. Federal Register. 67, 18: 3940-4098.

Witter, M.S. 1990. Evolution in the Madiinae: Evidence from enzyme electrophoresis. Annals of the Missouri Botanical Garden. 77, 1: 110-117.

Newspaper Articles

Miller, Ken. 1992 June 23, 1992. Two more Hawaii plants given federal protection. Honolulu Star Bulletin; Honolulu, HI. 1 pp.

Reports

Carr, G.D. 1982. Unpublished status survey of Wilkesia hobdyi St. John (Hobdy's iliau). U.S. Fish and Wildlife Service. p.24.

USFWS. 1995. Recovery Plan for the Kaua'i Plant Cluster. Portland, OR: U.S. Fish and Wildlife Service. p.270.

Wood, K.R.; LeGrande, M. 2002. Biological Inventory of Upper Pohakuao Valley North & South Falls Region, Na Pali Coast State Park, Kaua'i, Hawai'i, with information concerning the distribution and abundance of Flueggea neowawraea (Euphorbiaceae) & Oceanodroma castro (Hydrobatidae). Special Report Prepared for the Department of Land and Natural Resources Division of State Parks. p.21.

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This profile was updated on 3/4/2010