Acacia koaia is endemic to the Hawaiian Islands. It has been recorded from the islands of Kauai, Oahu (a recent find, possibly planted), Molokai, Maui, Lanai, and Hawaii. Acacia koaia is or was a dominant tree in certain areas. However, over most of its range its distribution is very spotty, with patches of trees widely separated. Many of these patches are the result of root suckering. Sexual reproduction appears to be uncommon in many areas. The number of individual clones in existence may still number several thousand. Because Acacia koaia occurs at relatively low elevations, and often close to inhabited areas, it has been severely impacted by ranching, agriculture and human-ignited fires. Other threats to the species are feral goats and pigs, deer, and invasive alien plants.
Threats to A. koaia include habitat degradation and herbivory by goats, and invasion of habitat by alien plant species. Because it occurs in low elevations, it has been severely impacted by historic ranching, agriculture and human-caused fires. (NatureSer
Number of populations: many (USFWS 2001)
Number of plants: >1000 (USFWS 2001)
Seeds of A. koaia have been tested by the National Seed Storage Laboratory (NSSL), finding that they are orthodox and tolerant to drying and freezing. The laboratory germination time was four months (Yoshinaga 2002).
Judy and Will Hancock are assisting the Hawai'i Forest Stewardship Program (Kalopi Dryland Forest Restoration) in restoring the ridges of Kohala (Hawaii). They have been planting A. koaia on the leeward side of the Kohala Mountains since 1989 and claim that the shorter A. koaia are better adapted to the windy, dry Kohala landscape. The goal of the Kalopi project is primarily to restore native Hawaiian dryland forest. However, any wood from harvest from dead or thinned trees is valued for its beautifully grained wood (Hawaii Forestry News 2000).
The National Tropical Botanical Garden (NTBG) currently has ex situ holdings of 204 seeds in its seed bank, which represents four populations. In addition, 100 individuals from four populations are growing in the botanical garden.
1. Genetic studies are needed to confirm taxonomic and the phylogenetic status of A. koaia.
2. Genetic studies are also needed to confirm the distinctiveness between island populations.
3. Map genetic diversity in the surviving populations of A. koaia.
4. Test management strategies on invasive species and pest control for A. koaia.
Recommendations derived from M.H. Chapin, M. Maunder, and Wagner et al. (1999).
1. Establish a full seed bank collection of A. koaia representing all available populations.
2. Development of proper horticultural protocols including pest management for A. koaia.
3. Survey ex situ holdings and conduct molecular fingerprinting.
Recommendations derived from M.H. Chapin and M. Maunder.
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