The Lesson of the Toothless Island

Argemone glauca (pua kala) and Layasan albatross on Lehua islet, Hawaii
Photos by Ken Wood, NTBG

Far from the kitchens and gardens of Hilo, the clamor of Honolulu’s Chinatown and the eateries along Lahaina’s Front Street, tiny Lehua pokes its head out of the water off the northern tip of Niihau. At 290 acres, Lehua is Hawaii’s largest offshore islet, a crescent-shaped tuff crater floating like a mirage within view from Kauai’s western shores. An uninhabited volcanic lip too steep and dry to support humans or agriculture, Lehua is home to a restoration project that holds a valuable lesson about conservation and balance.

Bathed in almost constant sunshine, Lehua is surrounded by clear blue waters and, removed from civilization, at first glance appears to be an ideal “desert island” until you consider the reality of an extremely arid environment with scant resources.

Long ago Hawaiians likely used the island to gather birds, eggs and feathers and the remains of a kuula (Hawaiian fishing shrine) indicate Lehua was an important fishing ground. Only half a mile from Niihau, Lehua’s waters are filled with sea turtles, manta rays, whales and dolphins, but with a healthy shark population that includes occasional great whites, this is not Gilligan’s Island.

It is, however, one of Hawaii’s most important breeding grounds for seabirds, many found nowhere else in the Islands. According to the Offshore Islet Restoration Committee, a multi-agency group that surveys and protects over 40 of Hawaii’s largest islets, Lehua supports at least 35 species of birds like the red-footed booby, Newell’s shearwater, and the rare black-footed albatross. Unlike those on larger, populated Hawaiian islands, birds on Lehua thrive without dogs, cats, humans or cars.

Frequently overlooked, but of no less importance, are insects, including 11 species endemic to Hawaii.Many of these tiny inhabitants serve as plant pollinators and play an important role in maintaining the islet’s ecological balance.

Over the last century, the greatest damage to Lehua has come from feral rabbits and rats. Whether introduced intentionally or accidentally, these creatures have decimated native plants and some bird species while causing loss of vegetation, leading to soil instability and increased sediment runoff into the ocean, extending their impact beneath the waves. Before any restoration efforts could begin, the rabbits and rats had to be removed.

Today the U.S. Fish and Wildlife Service partners with the National Tropical Botanical Garden (NTBG) to reintroduce and maintain native plants, which are expected to improve nesting and habitat conditions for birds and help restore the islet.

NTBG’s Conservation Director, Dr. David Burney, explains the importance of the project. “Lehua has the best potential for long-term, large-scale conservation in the entire Hawaiian Islands. It has an extremely effective fence called the Pacific Ocean which pigs and goats can’t get over. It’s also the largest nearby island which can be reached in just under an hour by catamaran.”

Burney calls Lehua a “toothless island” for its lack of mammals, which he says will help native plants, land snails and birds like the endangered Nihoa finch get re-established.

Because Lehua receives very little rainfall, NTBG had to go to extreme lengths to water the young plants, transporting 100 gallons of fresh water at a time by boat charter, offloading on the Lehua’s southern flank below the plant introduction site. Using five-gallon water containers and surfboards, conservation staff ferried water to land, then used a small pump to drive the water to the highest point above the planting site. An open-valve gravity-fed drip line allowed small amounts of water to sustain the young plants as they became established. Today rain catchment tanks capture any precipitation.

Since botanist Ken Wood’s first trip to Lehua in 2001, he and fellow NTBG staff have visited at least 25 times to bring water, monitor progress and scatter native seeds.The Kauai-based institute is growing native plants like hinahina, naupaka, aalii, portulaca, naio (false sandalwood), ma`o (Hawaiian cotton), maiapilo (Hawaiian caper) and nanea (beach pea) for outplanting on Lehua. These, and native grasses like pili, kawelu and akiaki, have been selected based on fossil evidence that suggests they once grew on Lehua or neighboring islands.

As reintroduced plants recover, they join successful Hawaiian plants like ilima and pua kala (native poppy) which still occur naturally on Lehua.

And while Lehua is largely unknown by the general public, floating a world away from the dramas and delights of the human world, its health, balance and role as a connection between creatures of the seas, skies and soil, make it a prime example of the importance of conservation on all the Hawaiian islands and beyond.

NTBG’s Assistant Director of Living Collections and Horticulture Mike DeMotta says, “the lesson of Lehua is that it’s easier to preserve what we already have than to go back and fix it."

from edible Hawaiian Islands, Summer 2009 issue