Researchers in Hawaii are storing hundreds of threatened and endangered native plant species and keeping the rarest of those species from extinction.
There are over 400 threatened or endangered flowering plant species in Hawaii, according to the U.S. Fish and Wildlife Service — more than the rest of the country combined.
Around 240 of Hawaii’s endemic plant species have fewer than 50 individuals left in the wild.
The conservation of native plant species in Hawaii, known as the “extinction capital of the world,” is an increasingly important issue as human development and invasive species threaten them, and seed storage and micropropagation have become important methods for doing so.
Photo Gallery: University of Hawaii program saves threatened and endangered native plants
At the center of those techniques are the labs in two small cottages at Manoa’s Lyon Arboretum: the Seed Conservation Laboratory and the Micropropagation Laboratory, which make up the University of Hawaii’s Hawaiian Rare Plant Program.
Both labs have contributed heavily to plant conservation in Hawaii.
The Seed Conservation Laboratory is a seed bank that holds about 27 millions seeds. Cooled or frozen in the lab’s handful of refrigerators, those seeds represent 600 plant taxa, or 40% of flora native to Hawaii.
The seed bank’s origin can be traced back to the 1990s when Alvin Yoshinaga, its founder and a researcher with the university until he retired in 2010, began testing the theory that seeds from tropical plants cannot handle being dried, cooled and stored like seeds from more temperate environments can.
Yoshinaga eventually found that about two-thirds of native plants can be stored this way for years — 20 years and counting for certain species — and still be expected to germinate successfully.
“We were very surprised to find that they stored — at least some of them — much longer when they were refrigerated or stored desiccated,” Yoshinaga said. “At that time it was thought that Hawaiian seeds would not last if they were stored in those conditions.”
Nate Kingsley, a seed conservationist for the university, continues to test the viability of those seeds.
Kingsley, with help from a group of volunteers and students, dehydrates the seeds, usually collected by Department of Land and Natural Resources employees, in drying cabinets for about a month. He then organizes them into aluminum packets and plastic containers that can be stored in refrigerators or freezers for years.
Because it is cheap and space-efficient, seed banking is generally the first choice for plant conservation, and several seed banks exist in Hawaii for that reason.
But not all species can be stored in seed banks. Some seeds are sensitive to drying. Others are so rare in the wild that collectors can bring back only leaves, stems or immature seeds.
Many of those species are cared for at the Micropropagation Laboratory, where plant tissue cultures are grown in test tubes under controlled conditions. A tissue culture in a test tube can be kept alive by taking a cutting from it and planting it into a new test tube.
“We can overlap in our conservation efforts. So, what they (the seed bank) cannot store and propagate, we can do it, and vice versa,” said HRPP manager Nellie Sugii, who has done tissue culture work for over 30 years.
The Micropropagation Lab is the state’s premier tissue culture lab for storing rare native plants. And backed by the lab’s body of work, micropropagation has emerged in Hawaii as a successful and important technique that complements seed banking.
The lab, which was already functional by the time the seed bank was formed, houses more than 30,000 plants that represent over 200 native plant taxa. Of those, 150 are listed as threatened and endangered by the U.S. Fish and Wildlife Service.
As of May 2019, 13 of those species are thought to be extinct in the wild.
But as was the case with the haha, a shrub in the bellflower family which is endemic to parts of Oahu and Molokai, micropropagation can be used to save the rarest of plant species.
At one point the haha was found only in the Micropropagation Lab’s test tubes.
“This one is a real success story because the only remaining plants were germinated seedlings that were in this lab,” Sugii said. “Now they have plants that are growing and flowering and seeding again.”
The HRPP labs are important players in Hawaii’s plant conservation efforts, but they are not alone. While Sugii’s lab has the state’s micropropagation market essentially cornered for now, seed banks across the state collect and hold millions of seeds of their own.
Some of the larger ones include the National Tropical Botanical Garden on Kauai and the Oahu Army Natural Resource Program.
The NTBG’s first seed collection dates back to 1989, and today it has over 14 million seeds representing over 900 taxa. Most of the seeds are from species native to Hawaii, but some are from around the Pacific, according to Dustin Wolkis, seed bank manager at NTBG.
OANRP houses about 12 million seeds at Schofield Barracks on Oahu. Its seed bank is used to support about 50 endangered species on land managed by the Army.
There are seed banks in all Hawaii’s counties, and most are part of the statewide Hawaii Seed Bank Partnership, a collective of dozens of organizations and state agencies that gather, store and do research on plant material to protect native plants.
The partnership allows the seed banks to exchange data and material and coordinate large-scale projects like collecting ohia seeds to combat rapid ohia death, a fungal disease that has been plaguing ohia trees for years.
For the HRPP labs, conservation is successfully reestablishing threatened and endangered plant species where they were found originally.
With the help of state agencies such as the DLNR, they “really try to get them back to the island where they came from,” Kingsley said.
The COVID-19 pandemic has disrupted that process because the virus has slowed seed collections and germination experiments but has not stopped them altogether, he said.
“All we’re doing here is collecting data — that’s the whole point of the lab,” Kingsley said. “It’s important to keep them stored … but if I’m not constantly researching that viability through germination experiments, I’m not going to know the condition of my seeds; I could have dead seeds in storage, and I lose all that data.”
After germinating seeds he usually flies them back to their home island. But with current travel restrictions, Kingsley is now stuck with a growing number of rare plant seedlings with nowhere to go.
He is considering mailing the seedlings back home, even if they might die on the way there.
