Cooke's Koki'o

Kokia cookei

Description

Cooke's koki'o, Kokia cookei, is a small tree in the mallow family (Malvaceae) with a thick, smooth-barked, brownish-gray trunk and thick greenish branches that reaches a height of 11.5-15 ft (3.5-4.6 m). The palmate leaves are prominently veined. Profuse and showy orange-red flowers are adapted to pollination by nectar-feeding birds. The five-lobed and dry fruit is a dehiscent (splitting open when ripe) capsule; globose and up to 1.2 in (3 cm) in diameter, it produces seeds 0.4-0.5 in (1.0-1.3 cm) long that are covered with a short dense pubescence.

Isolated single trees of K. cookei can produce viable seeds. Botanist Joseph F. Rock collected seeds from the last wild K. cookei tree on Molokai in 1910. From a plant grown from one of these seeds, many subsequent generations of plants were produced from seeds until the late 1970s.

Unpublished research on pollination by Robert Hobdy, Dr. Herbert Baker, and Dr. Irene Baker reveals that K. drynarioides and K. kauaiensis are adapted to facilitate flower visitation and pollination by nectar-feeding birds. The bright red flowers of Kokia produce copious nectar with unusually high levels of amino acids, characteristics associated with bird-pollinated flowers. The flowers of K. cookei, although somewhat smaller than the other two species, nevertheless contain copious nectar.

Large grafted individuals of K. cookei can produce hundreds of flowers seasonally. Flowering K. cookei trees may have been important food sources for native nectar-feeding honeyeater birds. After the arrival of humans, extirpation of native birds from leeward Molokai may have greatly reduced pollination, and alien nectar-feeding birds such as Japanese white-eyes have not been observed visiting this tree. Honeybees do visit the flowers of K. cookei.

K. cookei can be a fairly long-lived tree. One of the original seedlings produced from the last wild tree lived from 1915 to sometime after 1954; in contrast, grafted trees of K. cookei often have shorter life spans than this more than 39 year maximum.

K. cookei that have originated from seed flower as early as four years after germination. It has been observed to flower and fruit from about February to June or July. The flowers remain fresh on the tree for several days, but soon wilt after picking unless their stems are plunged into boiling water. There is a faint hibiscus odor to the flowers. The tree bears seed pods and flowers at the same time.

The genus Kokia is deciduous; however, in cultivation, K. drynarioides has some foliage year-round. Even with regular watering, K. cookei lose most of their leaves by September. In the fall of the year, the leaves turn a reddish color, like those of the false kamani or maple, and fall off, leaving the brown dried seed pods. There is a temporary rest period before the leaf buds appear, the dry pods still remaining on the tree more or less in a cured state until they at last fall off.

Of four subspecies of Kokia native to the Hawaiian Islands, two are Federally listed as endangered (K. cookei and K. drynarioides ), one is considered relatively uncommon (K. kauaiensis ), and the fourth is extinct (K. lanceolata ). Genus Kokia is a near relative to genus Gossypium, which includes cultivated cotton plants.

Habitat

The only historic habitat of K. cookei is dryland forest at an elevation of approximately 660 ft (201 m) on the western (leeward) end of Molokai near Mahana, northeast of Puu Nana. Photographs taken of the last wild individual of K. cookei and its habitat in 1913 show an over-browsed, arid, pasture-like site of barren soil, large boulders, and scattered non-native grasses. The tree stood on a rocky bluff all by itself. Some distance from it there were the remnants of a forest, a few scattered trees and the exceedingly rare vine Bonamia menziesii. All the trees were windswept, the crowns extending in oblong outline in one direction. On the ground lay scattered old minks of once glorious trees, among them a small dead tree of K. cookei. probably one of the original three trees discovered in the 1860s.

The soil of the K. cookei habitat on Molokai, relatively young with good drainage, is generally rich in plant nutrients. Rainfall on this leeward area is strongly seasonal with most of the approximately 20-25 in (50.8-63.5 cm) of annual precipitation falling in a few winter storms, then generally followed by arid summers.

Distribution

K. cookei, prior to its extinction in the wild in 1918, had natural occurrences only in dryland forest near Mahana, northeast of Puu Nana, in western Molokai. Three K. cookei trees were discovered on the western end of Molokai during the 1860s, but they could not be found again a few years later. In 1910, a single living tree was discovered and another one dead in a lonely dry canyon at the extreme west end of Molokai back of Mahana. This tree may have been one of the original three trees discovered some 50 years earlier. In June 1915, observers visited the last tree of K. cookei in the wild at Mahana and found it in extremely poor condition with only one or two branches still bearing foliage. They collected a few seeds that were lying on the ground; from these a number of seedlings eventually germinated. The full natural range of K. cookei cannot be determined due to the near complete loss of native, dryland forest on Molokai.

The species now exists as 23 grafted plants in five different locations on the islands of Maui, Molokai, Oahu, and Hawaii. Seven individuals are in artificial cultivation facilities on the islands of Maui and Oahu. One individual is located at a private residence on the island of Hawaii. The remaining 15 individuals are in small outplanting sites on Molokai Ranch lands, at Puu Nana. Puu Nana is within 1.2 mi (1.9 km) of Mahana, the site where the original wild plants of K. cookei were discovered.

Threats

The reasons for the historical decline of K. cookei were habitat conversion, grazing animals, loss of native pollinators, and seed predation. The present low number of individuals and populations of K. cookei is the result of catastrophic habitat conversion and a recent history of failed propagation efforts. A fire in 1978 at the Cooke's Kauluwai residence killed the last naturally rooted K. cookei plant. All K. cookei are now plants grafted onto rootstocks of related species. This technique, though successful in allowing for the continuing survival of the species, may have resulted in plants of reduced vigor and longevity compared to naturally rooted plants derived from seeds.

The primary threat to the continuing existence of this species is the lack of viable seed production, which may be due to genetic problems associated with severe inbreeding and loss of genetic variability. All living plants of K. cookei are clones and genetic copies of a single individual. The lack of viable seeds may also be related to poor vigor of grafted plants of the species. The plant used in cloning had produced viable seeds.

Conservation and Recovery

Five types of propagation have been attempted with K. cookei: seeds; cuttings; grafting; tissue culture; and air layering. Tissue culture is a method of sprouting roots and shoots from meristematic tissue by placing the tissue on a medium and applying a growth hormone. Air layering is a method of inducing root sprouting on branches by making small cuts on the branch, applying a root hormone, and wrapping in a moist, dark medium.

The single first generation tree that grew at the Cooke's Kauluwai residence from 1915 to the middle 1950s produced hundreds of viable seeds and about 130 second-generation seedlings. None of the outplanted seedlings were still surviving when they were checked in the 1970s. Whether the failure of these plantings was due to ill-suited growing conditions or to lack of seedling vigor caused by severe inbreeding depression is unknown. K. cookei last produced viable seeds in 1974-1975. Living K. cookei were grafted from the last individual known to have produced viable seeds. Though none of the seedlings grown from the seeds of this clone have survived, its ability to potentially produce viable seeds is encouraging. Upon examination at maturity, seeds produced since the early 1970s have deformed embryos or even lack them entirely. Embryo culture techniques therefore appear to be the only promising methods for producing seedlings. Plants in the west Molokai exclosures continue to produce nonviable seeds.

Both K. drynarioides and K. kauaiensis can be successfully propagated by air layering. Though attempts to air layer K. cookei have thus far been unsuccessful, both Waimea Arboretum and Botanical Garden and Maui Division of Forestry and Wildlife are interested in continuing with this technique. Experimentation with air layering of K. cookei is currently being carried out at Waimea Arboretum and Botanical Garden on Oahu.

Two grafted K. cookei plants at Kahului on Maui, both four or five years old, flowered prolifically in 1991, producing over 850 flowers and 88 seed pods, but no viable seeds. Within a few months, both trees had died. Examination of the grafted rootstock revealed that although the K. cookei top section was relatively intact, the K. drynarioides rootstock had rotted. Researchers believe that the death of the two plants was a result of depletion of resources after the heavy spring-summer flowering season. Since that time, they removed flower buds on the remaining K. cookei plants at the Division of Forestry and Wildlife's Kahului baseyard in hopes of prolonging the life of stock plants for grafting and air layering. At Waimea Arboretum and Botanical Garden, staff do not remove the flower buds of K. cookei. Only one of the larger plants flowers regularly at Waimea, and immature seeds are collected for embryo culture at Lyon Arboretum.

An important part of the strategy for conservation of K. cookei has been the outplantings on west Molokai as an emergency effort of Maui District of the Division of Forestry and Wildlife, Molokai Ranch, Waimea Arboretum and Botanical Garden, and The Nature Conservancy of Hawaii. The two current outplantings at two locations are managed by the Division of Forestry and Wildlife. Both out-plantings are located at Puu Nana on privately owned Molokai Ranch lands; as of 1998, they contained 15 of 23 extant K. cookei individuals.

In 1991, former Hawaii Governor John Waihee participated in the first outplanting of eight K. cookei plants (grafted onto K. drynarioides rootstock) into two small exclosures constructed by the Division of Forestry and Wildlife staff on Molokai Ranch lands. Twenty-two additional plants of K. cookei were out-planted in 1992 in these same Molokai exclosures, bringing the total to 30 outplanted grafted plants, of which 15 were still surviving in early 1998. After the Division of Forestry and Wildlife personnel established a drip irrigation system and reduced fertilization, the plants have appeared healthier. Many plants flowered in 1995 and 1996 and occasionally set seeds. Three seed pods were produced in 1995 and 1996, but bore only nonviable seeds. Non-native grasses are removed from around the K. cookei plantings in the Division of Forestry and Wildlife exclosure.

The third small outplanting site originally had twelve K. cookei planted, but by early 1998 all of the plants had died. Two plants flowered for the first time in the summer of 1995, although no seed pods were set.

Despite heroic efforts to save this species, K. cookei is not currently safe from the threat of extinction. The most immediate threat to the survival of K. cookei is the low number of the 23 individuals in only five locations. Coupled with this is a lack of production of viable seed and the tendency of grafted plants towards short and unpredictable life spans. These factors increase the vulnerability of the species to extinction from random natural events.

Contacts

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Center
911 N. E. 11th Ave.
Portland, Oregon 97232
http://pacific.fws.gov/

Pacific Remote Islands Ecological Services Field Office
P.O. Box 50088
Honolulu, Hawaii 96850-5000
Telephone: (808) 541-1201
Fax: (808) 541-1216

References

Kimura, B. Y., and K. Nagata. 1980. Hawaii's Vanishing Flora. Oriental Publishing, Honolulu.

Sohmer, S. H., and R. Gustafson. 1987. Plants and Flowers of Hawaii. University of Hawaii Press, Honolulu.

U.S. Fish and Wildlife Service. 1979. "Determination of Kokia cookei as an Endangered Species." Federal Register 44(211): 62470-62471.

U.S. Fish and Wildlife Service. June 1998. "Recovery Plan for Kokia cookei. " U.S. Fish and Wildlife Service, Portland, 86 pp.

Wooliams, K. R. 1975. "The Propagation of Hawaiian Endangered Species." Newsletter of the Hawaii Botanical Society 14(4):59-68.