By Jan TenBruggencate
Advertiser Columnist

The Nature Conservancy of Hawai'i has fenced a 108-acre area of Kalua'a Gulch in its Honouliuli Preserve on O'ahu, where a rare plant that became extinct in the wild a year ago is now thriving.

The plant is one of a family of native plants known to early Hawaiians as haha. It is a member of the bellflower family that is known to science as Cyanea pinnatifida.

It is one of dozens of related Hawaiian plants that grow like ti leaves, with a stalk and a spray of leaves at the top. Others include lobelias, brighamias and clermontias. The pinnatifida is different from most because its leaves, rather than being long and smooth-sided, have deep indentations. Its flowers are greenish white with purple stripes, and they hang in clusters of several to as many as 15 blossoms.

The species dwindled to a single plant in the Wai'anae Range. That plant died a year ago. But before it succumbed, scientists collected samples, and were able get them to grow in captivity.

The offspring of the last wild plant have been replanted into the same region, within the Kalua'a fenced area, and are healthy and fruiting.

"A species may have only a few individuals remaining, but each plant may produce hundreds of seeds, so the potential for reproduction is good," said Trae Menard, natural resources manager for the conservancy's O'ahu program.

"The Cyanea pinnatifida produces 50 to 60 seeds per fruit. One of the reintroduced plants currently has 60 to 70 fruits," she said.

The conservancy said pigs were believed to be the main threat to the species, and the fence keeps them out. Grazing animals, insects and trampling by both animals and humans are believed to be other threats.

Conservationist Keith Robinson of Kaua'i, who helped raise endangered members of the species, said rats are also an issue.

"Rats eat every part of that plant. They're a big problem," he said.

Both rats and pigs are introduced animals, and native plants evolved without them — thus without defenses against them.

The Nature Conservancy of Hawai'i said the fenced area—an 'ohi'a and koa forest— houses 23 other rare and endangered plants, along with 10 species of native snails and one endangered bird, the O'ahu 'elepaio.

The conservancy is planting other endangered species in the protected area, hoping to save them by removing the presence of threats to them.

"A species may be critically endangered, with only a few left in existence, but low numbers doesn't mean no hope. Don't write it off. Maybe one threat caused the reduction in numbers. If we can eliminate the threat the species can recover," Menard said.

Jan TenBruggencate is The Advertiser's Kaua'i bureau chief and its science and environment writer. Reach him at (808) 245-3074 or jant@honoluluadvertiser.com.