Waking Up in Eden (16 page)

But only DNA molecular analysis provides rock-solid evidence of genetic links. New techniques have led to the discovery of an almost unlimited amount of data, locked up in DNA molecules that can be extracted from fossils millions of years later.

By measuring one lineage of Hawaiian honeycreepers, such data suggests evolution produced about a 2 percent divergence every million years. Assuming a constant molecular clock, that puts arrival of the original honeycreeper ancestor in Hawaii at about 3.5 million years ago.

Rapid evolution is not only possible, but frequent. Change after arrival on the islands appears inevitable. Five species of endemic banana moths in Hawaii have evolved in the approximately one thousand years since humans introduced the banana to the islands. In Lake Lanao in the Philippines, four endemic genera of cyprinid fish evolved in ten thousand years or less. And new plant species have been discovered in the newly formed lava islands just over a century after the 1883 eruption of Krakatoa in Indonesia.

While scientists have studied birds, animals, and plants to decipher the secrets of evolutionary magic, evolutionary biologists regard the Hawaiian fruit fly —
Drosophila
— as supreme, the Mount Everest of DNA analysis for island biology. More than seventy-two scientists joined together in 1962 to form the Drosophila Genome Project to study this amazing insect over the next decades.

In part this is because there are so damn many species — more than one thousand, and still counting — of these tiny flies,
which have evolved into so many different ecologies. Before you wonder how even enthralled scientists observe differences between flies no bigger than a speck, it's helpful to know that there are two distinguishing physical attributes. Even closely related fruit fly species are distinguished by the shape of the male penis, so distinctive an identifying mark that it has been likened to a fingerprint in individual humans. Complex courtship behaviors also offer clues. Some species of males court females in the hopes of being chosen. Other
Drosophila
males aggressively jump on females from the get-go, in a more wham, bam, thank you, ma'am, style. Fruit fly DNA analysis is easy, compared to other organisms. The fruit fly develops giant chromosomes in its salivary glands and other parts of its larvae. Different-colored bands on each chromosome can be read like road maps into its genetic history.

These genetic maps show that the thousand-plus fruit fly species all descended from a single colonist, or at most two. Using DNA trapped by amber fossils, scientists found evidence that two distinct Hawaiian fruit fly lineages began to split 30 million years ago. Kauai, the oldest surviving high Hawaiian island with the kind of rain forest habitat favored by fruit flies, is only about 5.1 million years old. Thus, the fascinating implication: The original fruit fly colonization occurred on older, more northern islands in the chain that have since disappeared. As one island degraded and lost its wet mountain habitat, the flies moved south to greener pastures.

J
UST AS
DNA
TESTING
has been used to settle human paternity cases, it has turned up some surprising relatives in
the plant world as well. The genus
Viola,
for instance, is a moderate-sized and largely herbaceous group of about 550 species worldwide. Wagner identified seven Hawaiian species (and three subspecies) in his 1990
Manual of the Flowering Plants of Hawaii.
For years, botanists thought that the original violet colonist in Hawaii must have come from South America, as they shared a similar appearance. Wrong, according to chromosome data. DNA showed the Hawaiian violets to be closely related to those in Alaska and along the Bering Strait:
Viola langsdorfii
. They don't look alike. The Arctic violets grow classic pansy-like flowers and circular leaves that we would all recognize as similar to common violet houseplants, while the Hawaiian violets sometimes grow into shrubs as tall as twelve feet.

The evolutionists only briefly puzzled over how a violet from the Arctic region could get to Hawaii. Obvious. By air. More than fifty species of migrating birds breed in the Arctic but winter in Hawaii. Conducting their own Darwin-like experiments, modern-day scientists trapped birds to examine their feathers, finding plentiful evidence of seed stowaways.

Not all new arrivals in Hawaii built dynasties. Wagner showed that 10 of the original 291 original plant colonists radiated into multiple new adaptations, so many that they account for about half of Hawaii's plant diversity of about one thousand native species. Of native birds, only the Hawaiian honeycreepers diverged into radiations. The 19 other native Hawaiian bird lineages exist in only one form.

Once established in their new tropical habitats, many of the newly evolved species lost their competitive edge. Plants discarded the ability to emit toxins, or the armament to deter herbivores with oils, resins, stinging hairs, or coarse textures. It's
as if they expended all their energy into fitting into the new surroundings, and then kicked back, luxuriating in paradise. Under rapid, though irreversible, adaptation, some Hawaiian plant and animal species became excessively specialized to their niche environments, some no larger than a single valley. They lost whatever immunities and resistances they once had, becoming vulnerable to any import of disease or parasite. While this loss of competitive ability is exhibited in endemic island species around the world, nowhere are the native plants so poorly equipped for competition than in Hawaii. There is no easy explanation, but it means that almost any continental species of plant seems capable of moving in and annihilating the native inhabitants. Grazing by human-imported cattle and goats and rooting by pigs aids the death marches of these alien species, as weeds thrive on newly disturbed soil. Moreover, the native Hawaiian species show poor ability to replace themselves after disturbance.

This pernicious habit of alien invaders to move into newly plowed ground provides a particularly dismal outlook for conservation efforts. We can work like hell to weed the aliens by pulling up roots, but it only disturbs the soil and thus welcomes more intruders. And many of the invaders are spread by birds that eat their seeds and then widely excrete them like crop dusters. “Not only are weeds well-entrenched in many areas of the Hawaiian islands, but efforts to remove them would very likely only renew and widen the areas of disturbance and encourage more weedy growth than before,” noted Sherwin Carlquist in his 1974 landmark book,
Island Biology.

But all this genetic theory is difficult. When I came to the case of the Hawaiian silversword, I had a better sense of how
the miracle of evolution can turn a lowly weed into a majestic tower of a plant.

Tourists come from continents away to trek up the cindercovered dry slopes of the dead volcano of Haleakala on Maui. Many travel an hour and a half up the winding mountain road in the dark to watch dawn creep up over the crater's 10,023-foothigh summit. Others come to see the great silversword,
Argyroxiphium sandwichense.
As it nears death, it produces a spire of upward-turned, silvery bayonet-type spears. From its center rises one stem, up to six feet tall and covered by hundreds of purplish rosette flowers. And while its royal appearance is truly remarkable, its story is what draws the crowds.

Most likely birds carried sticky, resin-coated seeds from a now-extinct tarweed that was growing in coastal California. The avian carriers flew across the ocean, unknowingly delivering seeds and depositing them into the evolutionary cauldron of Hawaii, where they underwent a rapid transformation into the dramatic Hawaiian silverswords, greenswords, and some twenty-eight other island species in what is called “the silversword alliance.” Originally in the sunflower family, in Hawaii tarweeds grew tall. And low. Leaf anatomy developed into varied shapes.

One species grows on Kauai's rainy Mount Waialeale. Another Kauai silversword cousin grows into a ten-foot-tall onestem tree. Dryland species on Hawaii and Maui sprout hairs, thick leaves, and different internal tissues to cope with drought. Some of the dry land relatives form matlike clumps in lava fields. One wetland silversword species evolved into a vine. Other silverswords adapted to wet, poorly drained bogs. Or Alpine desert. Midlevel forest. Species moved back and forth between
such niche climates at least five, and likely more, times over the last few million years, suggesting that a change of ecologies was fundamental to its diversification.

While the silversword exemplifies the drama of evolution, its near extinction illustrates both human destruction and human rescue.

Climbers to the Haleakala Volcano summit used to prove they had reached the summit by plucking a silversword flower and taking it home. Although the volcano was declared a National Park in 1916, park rangers didn't crack down on this vandalism until the 1930s. The first official count of silversword, in 1935, estimated that the total population had dwindled to four thousand individual plants.

Thanks to intensive replanting projects, the population swelled to 64,800 silverswords by 1991. Using Steve Perlman's paintbrush breeding techniques, Hawaiian Silversword Foundation volunteers and state foresters pollinated a cliff-dwelling variety, then collected seeds and grew thousands of seedlings in the University of Hawaii's Center for Conservation Research.

My own experience with trying to weed Kauai of the ivy gourd left me feeling that no matter how massive our efforts, they would probably only succeed in small pockets. Yet the silversword projects demonstrate how dedicated individuals and institutions can snatch a few species from extinction. Sherwin Carlquist, the author of Hawaii's evolutionary history, offered a fair-minded and plausible challenge: If there are reasonable, simple, practical measures to conserve the earth's most fragile inhabitants, why not take them?

T
HAT
J
ANUARY AFTERNOON
the
pueo
swooped in circles, staking her territory around Garden headquarters. Small and gray, this Hawaiian owl flies in daylight. I watched through the window in Dr. Klein's office as a group of us met to review the year's final budget numbers. As always, Dr. Klein commanded the head of the conference table, surrounded by easels holding architectural drawings of his expansionist plans for all of the Garden properties. Many donors liked to wait until December to review their tax bills before deciding how much to give away in charitable deductions. We sweated in the final days of the year as we opened envelopes that contained checks from board members of $5,000, $20,000, $50,000, and more.

Two or three times a day, Doug Kinney, the Garden's chairman of the board, telephoned from his Florida golf retreat, always growling, asking for the latest figures. A businessman, he wanted to report that the Garden had ended the year in the black. “How much do we need?” Doug demanded. If we hadn't received an expected gift, he called the reluctant trustee to remind him or her to step up to the plate.

“And so we balanced the budget,” Dr. Klein announced to
the gathered staff. “But I submit,” he said, his pasty complexion turning the telltale pink that signaled high pique, “that balancing the budget is not the mission of the Garden. Education and research and conservation are the mission of the Garden.”
Right on, Dr. Klein!

My attention faded from the staff meeting. As always during times of sorrow, my work sustained me, giving me a focus. The last two months blurred together in a river of grief as I recovered from my father's death. At age eighty he was still working two days a week, though he had grown frail from a series of small strokes. We had expected it when the massive, killing attack came. Still, I had not anticipated the penetrating sadness, the sudden engulfment in memories that brought sharp pain and the realization that he was gone forever.

Dr. Klein's secretary interrupted the staff meeting to ask, “Lucinda, are you taking a call from June in Minneapolis?”

“Oooh. That call I'll take,” I told the group and got up from my chair to go to my office, happy to escape for a few minutes. I knew that my mother expected a visit from my nephew, Will. But my sister-in-law was on the phone to report that Will had been waiting at the Connecticut airport for three hours and Mom hadn't arrived to pick him up.

It was already 9 p.m. in Connecticut. I called Chuck, the young lawyer who lived across the street from my parents' house. “The house is dark,” he reported. “I'll go over. Weird. I didn't see her get the Sunday paper yesterday. There was an ice storm here, and I don't think she's been out of the house for three days.”

I put down the phone and went back into Dr. Klein's office. Forty-five minutes later came the second telephone call. “I better
take that,” I told Bill and the others at the meeting, laughing. “My mother seems to have gone off somewhere, so there's a family alert.”

“Lucy, your mother is dead,” Chuck said.

R
ITUAL TELLS US
what to do. Call relatives. Plan another funeral. Go home to Connecticut again. I closed the door of my office and started telephoning. When I heard a knock on the door, I opened it to see Janet Klein. Bill had become so worried about me that he had called her in.

Later that night, Bill and Janet arrived at my cottage door, expressions of concern on their faces. I had turned down their dinner invitation, as I needed to pack for another emergency red-eye flight to Connecticut.

They carried twin Styrofoam takeout containers from their favorite Italian restaurant. “We couldn't decide whether you'd like spumoni or chocolate mousse, so we brought you both,” Bill explained. Food, particularly chocolate, at a time of grief and crisis is never a mistake. I made tea and we sat in the living room as Sam the cat entertained us by walking from lap to lap in an oddly companionable evening. Instead of talking about the looming funeral, they decided to distract me with Garden and island gossip.