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 pristine lands existed in splendid isolation. Then the Polynesians introduced rats and lizards along with their crop plants. 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. The only four P.viscosa palms known to exist in the wild grow along the Powerline Trail on the eastern side of Kauai. Not long ago, NTBG botanists were thrilled to discover a fifth, a seedling that had sprung up alongside the others. When the scientists returned to the site, the seedling was gone, with a gaping hole and telltale shovel marks in its place.
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. Those four P. viscosa beside the Powerline Trail, for instance, now have 16 cousins growing in captivity.