Hawaii’s Plant Extinction Prevention Program

Saving Native Species with Teamwork!

Hawai‘i’s Plant Extinction Prevention Program saves rare native plants through team- work. When the last remaining individuals of a rare plant species are dis- covered, they can be protected, propagated, and planted back out into secure areas to reclaim their role in native ecosystems. Hawai‘i’s Plant Extinction Prevention Program saves rare native plants through team- work. When the last remaining

Without this intervention, more native plants would have gone extinct. The Hawaiian Islands are the most isolated land masses on Earth. This isolation has created a biological hotspot where approximately 90% of the native flora is endemic (found nowhere else in the world). Hawai‘i’s unique flora is at risk of extinction, primarily due to the ongoing impacts of invasive alien species. Now, Hawai‘i has the regrettable distinction of being “the endangered species capital of the world,” home to 40% of all endangered plants in the United States. Although Hawai‘i has less than 1% of the landmass in the United States, there are 425 Threatened or Endangered plants. Most of these plant species are critically endangered, having fewer than fifty individual plants remaining in the wild. In these cases, a single animal, landslide, storm, or new disease can wipe out an entire species. So far, over one-hundred plants only found in the Hawaiian Islands have gone extinct. The Plant Extinction Prevention Program is a project of the Pacific Cooperative Studies Unit, of the University of Hawai‘i at Mānoa and is supported by partners at the State of Hawai‘i Division of Forestry and Wildlife, and the Pacific Islands Fish and Wildlife Office, and with grants and donations from public and private institutions.

With staff located on Kaua‘i, Oahu, Maui, Moloka‘i, and Hawai‘i Island, PEPP works wherever the plants live. Field surveys are done to search for rare species along roadsides and in remote locations. New locations of rare plants are discovered every year, but most often these populations are in decline. Whenever possible, threats are immediately controlled, and long-term protection is planned for the area. Fences are built to exclude feral animals such as pigs, goats, cattle and deer which trample and eat vulnerable native species. Rats and mice devour seeds and damage small plants. Sometimes this is so severe that there are no seedlings or younger plants of rare species. Aggressive invasive plants can smother native plants and alter soil and microclimate conditions to favor their own survival, killing off native species. Many of these weeds are adapted to establish quickly after wildfire, blocking native species from regenerating. As the frequency of these fires increase in Hawai‘i, so does the spread of invasive plants. New pathogens to our islands, like Myrtle Rust (Austropuccinia psidii) and those causing Rapid Ohia Death (Ceratocystis spp.), are causing further disruption of native forests allowing invasive plants to take hold. Many native plants rely on other organisms for pollination and dispersing seeds. When birds, moths, and other native animals go extinct, so do the plants that rely on them.

In 2020, a new species of native plant was described from the only known individual discovered in a remote location in West Maui. While exploring the steep slopes of Helu above Lahaina, PEPP botanist Hank Oppenheimer and colleague Jennifer Higashino found a single large plant in the deep shade of healthy ‘ōhi‘a forest. The new plant, named Cyanea heluensis, is related to other native plants known as hāhā, but has unique leaves and gently curved long white flowers. The flowers of this and other related species are pollinated by birds and the orange fruits are attractive to fruit-eat- ing native birds that would disperse the seeds. Since first discovering years ago, Mr. Oppenheimer has managed a team of specialists to prevent its extinction. From the highly skilled helicopter pilots at Wind- ward Aviation who being him to the site, to the horticulturists at Lyon Arboretum and the Olinda Rare Plant Facility who developed methods to clone and grow the new species, each has played an important role in saving this species. With it now secured at State nurseries, Cyanea heluensis can now be multiplied and planted back into its home on West Maui.

Since PEPP started over twenty years ago, an average of one species has gone extinct in the wild every year; but not before being saved in cultivation. Direct intervention to collect seeds, cuttings, or other propagative material has been successful. There are now at least twenty-four species that have been saved before their last plants died in the wild. Salvaging the last plants to rescue a species can only be done with teamwork. Talented propagators at botanical gardens, seed banks, and specialized plant nurseries across the state maintain these plants until they can be returned to the wild. Protecting and restoring habitat provides new homes for rare species to recover.

Stenogyne bifida is an endangered species known only from the island of Moloka‘i. It was first described in the 1870’s and was listed as a State and Federal Endangered species in 1992. By 1995, there were just 12 plants known and it was collected and secured in tissue-culture at Lyon Arboretum. Despite being fenced and protected, the population continued to decline.


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About the author  ⁄ Garrett Webb

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