NTBG’s Seed Bank: An Investment Pays Off

From humble beginnings, NTBG’s Seed Bank and Laboratory has grown into a valuable repository for Hawaii’s irreplaceable genetic botanical wealth

By Jon Letman, Editor

Although its name often goes unmentioned, the island of Kahoolawe sits at the heart of Hawaii, both physically and spiritually. Part of the ancient geologic formation Maui Nui (Greater Maui), the 45-square-mile island with the jagged coastline is roughly triangular in form with deeply indented coves and a club-shaped peninsula on its southern coast.

The island, revered as a physical manifestation of the ocean deity Kanaloa, is sacred to Native Hawaiians who see it as a place of recovery and restoration. Kahoolawe is the piko (navel or center) of Kanaloa and has been called the crossroads of past and future generations of Hawaiians.

Perched in the lee of Maui’s towering volcano, Haleakala, Kahoolawe is one of the driest of the main Hawaiian Islands, receiving less than 25 inches of rain a year. Just 11 miles long and seven miles wide, the island has suffered the ravages of wild goats (introduced as a gift by Captain George Vancouver in 1793), cattle and sheep ranching, and more than half a century of bombing and military testing by the U.S. Navy (1941-93).

By 2004, unexploded ordnance (UXO) had been cleared from about 75 percent of Kahoolawe’s surface, but today only about 10 percent of the island is considered safe to dig to the depth of four feet — no deeper. Additionally, 25 percent of the island remains uncleared of UXO with access restricted and restoration work strictly controlled.

Rugged but Fragile Environment

Administrating the island’s rugged but fragile environment is the Kahoolawe Island Reserve Commission (KIRC), whose mission includes the restoration of the island’s dryland forests, shrublands, and the surrounding reef ecosystems. KIRC operates with funding from individuals, grants, and state funding.

Under KIRC’s management, the island is gradually recovering, but outplanted seeds and seedlings still face multiple threats. Drought, flash floods, erosion, seed predation from rodents, invasive plants, and insects such as the Erythrina gall wasp and bruchid beetle all pose formidable threats.

Since the 1990s, NTBG Research Biologist Ken Wood, occasionally in collaboration with fellow botanists, has been collecting seeds from the gulches, cliffs, and coastlines of Kahoolawe and its steep offshore islet Puu Koae, and seastack Aleale. Collections have focused on a dozen Hawaiian species that include ihi (Portulaca molokiniensis), native caper maiapilo (Capparis sandwichiana), and other shrubs, trees, and vines that can survive the island’s inhospitable conditions.

Between 1995 and 2001, 194 collections (accessions) were made and deposited in NTBG’s then-nascent seed bank on Kaua‘i. In 2008, all of those seeds were transferred to frozen (-18°C) or refrigerated (+5C°) storage.

Until 2017, KIRC had withdrawn only a very limited number of seeds from NTBG for reintroduction to Kahoolawe, but grant funding from the Hawaii Department of Land and Natural Resources Commission on Water Resource Manager-Water Security Advisory Group in 2017 allowed KIRC to request nearly half of the seeds[1] of target species including two members of the legume family — Erythrina sandwicensis or wiliwili tree, and Sesbania tomentosa or ohai, which grows as a coastal shrub. Three-thousand seeds from the native Hawaiian cotton (Gossypium tomentosum) or mao, were also sent to KIRC.

The Journey Home

Last November, as she prepared the seeds for their journey home, NTBG Science and Conservation Specialist Margaret Clark explained, “I’m sending samples of each of these parent plants so that they have the widest possible genetic representation, because the more genes that are in the pool that they plant, the more diversity there will be in succeeding generations, and the more long-term survivorship there’ll be.”

Opening a foil packet, Margaret gingerly removed a handful of fluffy brown mao seeds, holding them like tiny cotton balls. “They’re real soft, but they’re not as long-lived, we think, as the Erythrina and the Sesbania. We’ll see.”

With uncertain survival rates, KIRC has requested twice the number of seeds it expects to plant out to allow for seeds that might not germinate.

Once KIRC receives the seeds from NTBG, they will be grown out at a nursery on Maui. Plants will then be hand-carried back to Kahoolawe for outplanting during the wetter winter months.

James Bruch, a KIRC Natural Resources Specialist, says the reintroduction of plants, and the native insects that will follow, is a first step in restoring the habitat. Because much of Kahoolawe’s land is still not safe for digging, KIRC has developed a technique to revegetate on the surface in soil planter beds built on top of hardpan.

“We really appreciate the service that NTBG is doing because without it, we wouldn’t be able to do projects like this,” says James.

KIRC’s planting, which began in March, is expected to continue through June. As the partnership between KIRC and NTBG shows, seed banking is one sound investment that offers a payback with real growth potential.

[1] KIRC has requested 600 Erthrina, 1,000 Sesbania, and 3,000 Gossypium seeds.

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