Passage IV

NATURAL SCIENCE: This passage is adapted from the article "Hawaii's Native Palms" by Mike Grudowski (©2002 by Smithsonian lnstitution).

Field botanist Ken Wood works for the National Tropical Botanical Garden (NTBG), on Kauai. He spends a lot of time looking for rare palms. Today he hopes to pluck a few seeds from a fan palm of the genus Pritchardia, a group that encompasses Hawaii's only native palms.

There are 27 species of Pritchardia, 23 of which are found in Hawaii. Eight are officially classified as endangered, but Wood is convinced others as well face the threat of extinction. Not long ago, he took a census on East Maui of one of them, P.arecina. "There are only 500 left and there is no regeneration. When there's no regeneration, you don't need statistics to show that the species will die off."

As is the case with endangered plants and animals in general, a disproportionate number of endangered palm species are found on islands. If they didn't constitute such a varied family of plants, palms might be in even worse shape. They grow in African streams and 9,000 feet high in the Andes. They're found in sweltering mangrove swamps in Southeast Asia and in blizzard-lashed highlands in the Himalayas. Some top out at six inches, and others tower upwards of 200 feet; rattan palms (which grow as vines) can in length. "Because palms exceed 600 feet are so diverse, they've risen to dominance in many ecosystems," says Scott Zona, a palm botanist at Fairchild Tropical Garden in Coral Gables,Florida. "They're characteristic of savanna forests, rain forests, gallery forests along rivers, and mangroves."

Palms put food on the table for people directly and indirectly. Almost half a million people in the South Pacific rely entirely for their livelihood on coconut palms grown commercially on Fiji and other Pacific islands, like Samoa. Coconut oil and coconut milk are important food sources. There are very few parts of the palm that somebody, somewhere, hasn't found useful.

According to Melany Chapin, who oversees NTBG's collections of live plants, the main problem with Hawaii's native palms is that "they don't have any defense mechanisms, because they never had any native predators to contend with." For millions of years, Hawaii's lands existed in isolation. Then the Polynesians introduced rats and lizards along with their crop plants (coconut palms, taro, and breadfruit). Captain James Cook and other explorers left behind pigs, sheep, goats and cattle. Mongooses, imported from Jamaica in the 1880s to prey on rats in sugarcane fields, developed a taste for native birds.

Today, just about any time a Pritchardia tries to reproduce, Hawaii's biological invaders go to work. Rats devour most seeds before they can germinate. Goats munch any seedlings that manage to sprout. Pigs rut up the ground, damaging fragile root systems and causing erosion in steep terrain. Vickie Caraway, a botanist in Hawaii's Division of Forestry and Wildlife, says that introduced weeds are a big problem too. They form thick mats over the soil in many areas preventing the palm seeds from germinating.

Habitat destruction compounds the problems. Over the centuries, much of Hawaii has been burned, bulldozed and built up with cane and pineapple fields, towns, condominiums, hotels, marinas and golf courses. The lowland dry forest, where native palms once dominated, has taken the hardest hit; more than 96 percent of it is gone. Unethical plant collectors make things worse still.

As daunting as these combined threats are, hope remains. On the north shore of Kauai, NTBG is restoring Pritchardia to the wild in a 1,000-acre preserve. But most of the Pritchardia seeds Wood and his fellow scientists bring back from their expeditions get planted in the garden's 286-acre grounds on Kauai's south shore. There and in other protected tracts, the staff is cultivating a kind of botanical menagerie of rare palms, in hopes of preserving as much genetic diversity as possible. These plants provide a significant hedge against the possibility of extinction. For instance, the only four P. viscosa palms known to exist in the wild grow along a trail on the eastern side of Kauai. Now those four have 16 cousins growing in captivity.

Several groups are trying to save Hawaii's palms by protecting their habitat. About two million acres of native forest and scrubland remain intact, according to the Nature Conservancy, and a quarter of them are man-aged by federal or state agencies, or private groups. On Maui,Oahu and Molokai, a number of land partnerships have been formed in recent years, bringing together all manner of public and private landowners in cooperative efforts to thin out invasive species and protect native ones.