A native plant thought to be extinct in the wild has been reintroduced in West Hawaii after surviving specimens were found by chance last year.
Delissea argutidentata is a species of flowering plant native to the Big Island whose habitat in West Hawaii has been steadily reduced by cattle grazing, driving the plant to the verge of extinction. The last known wild specimen died in 2002, and although some outplantings survive today in controlled settings, the species was considered extinct for nearly two decades.
That changed in March 2021, however, when three surviving plants were found in a remote crater on Kamehameha Schools land in West Hawaii. Since then, through the work of Kamehameha Schools, the state Department of Land and Natural Resources and the Three Mountain Alliance, 30 young Delissea specimens have been replanted in that crater.
The three surviving Delissea were found growing on a dead stump by a TMA staff member collecting seeds from other plants in the area.
“Almost immediately, we all knew what it was,” said Amber Namaka Whitehead, Kamehameha Schools’ senior natural resources manager. “It’s a storied plant, and everyone knew it used to be growing here. Whenever we go out there, we’re always scanning the trees, hoping we might see one that somehow survived.”
Whitehead said the Delissea can grow up to 35 feet tall with an unbranching trunk topped with a round cluster of leaves. The three survivors were not nearly that tall — about 6- or 7-feet-tall at most, she said — but two were reproductively mature.
The plants were found within one of several fenced enclosures created by a previous tenant of the land in the 1970s. Whitehead said that enclosure was likely the key to the specimen’s survival.
“It’s evidence that protective fencing really can help,” Whitehead said, explaining that ungulates such as cattle and pigs nibble at the trunks of Delissea, disrupting their growth.
Since the discovery last year, the three organizations have saved seeds and fruit from the three plants and planted them at the Volcano Rare Plant Facility. Those seeds have grown into 30 young Delissea that have been replanted in a West Hawaii crater whose location is being kept confidential.
So far, those 30 specimens have a 100% survival rate, Whitehead said.
The crater appears to protect the Delissea from drought conditions. Whitehead said that the three survivor plants must have endured fairly significant drought conditions over the past decades, and said the crater might be used to house other rare and endangered plants in the future.
Whitehead said she hopes that more seeds will be distributed throughout the species’ former range so that, eventually, it can once again become a common sight among the island’s forests.
“It’s such an amazing success story,” Whitehead said. “It gives us so much hope for the prospects of other endangered species.
“Things look so dire for so many endangered species, and to see this one come back like this, it gets us energized.”
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
