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Hawai‘i at the Crossroads
Site of this year’s World Conservation Congress, the Hawaiian Islands present a microcosm of global environmental challenges
07-15-2016 // Jessica Snyder Sachs
An endangered Hawaiian monk seal swims off the west coast of O‘ahu. One of the rarest pinnipeds on Earth, the seals are outfitted with plastic tags on their rear flippers so researchers can identify and track each individual.
ON AN EARLY MORNING THICK WITH VOLCANIC HAZE, Hannah Kihalani Springer looks out the window of her home 2,000 feet above the North Kona coast of Hawai‘i and across the homestead where her family has lived for generations. On this “voggy” day, she sees a landscape dominated by the nonnative fountain grass that was introduced as an ornamental plant a century ago. Springer recalls how, during her childhood, this African bunchgrass exploded across the land surrounding her home, invading native scrub and dry forest.
On clear mornings, Springer still can see remnants of that forest on surrounding hillsides, where bordering lava fields have protected forest patches from fierce, grass-fueled wildfires. For the past five decades, her family has helped nurture these remnant woodlands, which provide habitat for some of Hawai‘i’s most iconic birds—species such as the ‘apapane and ‘amakihi, two of Hawai‘i’s surviving honeycreepers. Both birds need native forest for insect foraging and nesting. Sadly, some 90 percent of the state’s original dry forest has been lost to agriculture, overgrazing by feral livestock and introduced game animals, and the incursion of invasive plants such as fountain grass.
One of Hawai‘i’s surviving honeycreeper species, an ‘apapane flutters atop the native dryland plant māmane.
In the 1990s, Springer’s family joined other local people in an ambitious project to enlarge their region’s remaining forest through arduous hand weeding and replanting the native understory shrubs and vines needed to support endangered trees such as the kauila, a type of buckthorn, and the flowering uhiuhi, ‘aiea and koki‘o trees whose blossoms adorn traditional Hawaiian lei. Their work drew the attention of state and federal agencies and environmental education programs. In 1994, the
Hawai‘i Forest Institute began formally managing this restoration effort, and today the Ka‘ūpūlehu Dryland Forest is one of the largest intact swaths of a once-widespread ecosystem found nowhere else on Earth.
“We are people of the land with lessons to share from our intimate relationship with our landscape,” says Springer, former president of the National Wildlife Federation affiliate
Conservation Council for Hawai‘i. “Our mo‘olelo—our history—describes the conditions our ancestors have observed and responded to since time immemorial. How the landscape changes when a volcano erupts or a family introduces cattle has taught us the nimble response—how to always be preparing for the next change.”
Preparing for change is crucial in the state of Hawai‘i, whose capital, Honolulu, is hosting this year’s quadrennial
World Conservation Congress. With the theme “Planet at the Crossroads,” the congress will convene thousands of conservation scientists, policymakers and indigenous practitioners during the first 10 days of September. “We truly are at the crossroads,” explains Inger Andersen, director general of the
International Union for Conservation of Nature (IUCN), the meeting’s sponsor and host. “Never before in history will what we have done in one generation have such a lasting impact on the future of our planet,” she adds. “Lessons learned from island systems such as Hawai‘i are critical to this work because they bear the first impact of ecosystem shifts such as climate change.”
Unmatched Diversity—and Loss
For more than 70 million years, the extreme isolation of the Hawaiian Islands—the planet’s most remote archipelago—fostered the evolution of spectacular biological diversity. To get here, the ancestors of Hawai‘i’s native plants and animals either had to fly, swim, float or hitchhike in. Once arrived, these species evolved to fill a wide diversity of habitat niches largely free of competition, predation and trampling. The extraordinary results of that process include the Hawaiian koa tree, a thornless version of the prickly acacias found elsewhere; more than 50 kinds of Hawaiian honeycreeper, many of which evolved elaborately curved bills allowing them to feed on just one or a few flowering plant species; and more than a dozen bird species that, in the absence of mammalian predators, evolved to be flightless. At the height of its biodiversity, before the arrival of the first Polynesians 1,000 to 1,200 years ago, Hawai‘i was home to well over 10,000 endemic plant and animal species, or species found nowhere else in the world.
Paradise in Peril
Sadly, the intricate webs of life that evolve in such isolation are extremely vulnerable to disruption by human development, climate shifts and introduced predators as well as other destructive species. Today Hawai‘i is known as the “extinction capital of the world” for good reason. Though the island chain makes up less than 0.2 percent of the U.S. land area, it accounts for about 75 percent of the country’s known plant and animal extinctions and about a third of all species that are listed by the federal government as threatened or endangered.
Historical and archaeological records suggest that the Hawaiian Islands underwent two great waves of extinction. The first followed arrival of the Polynesians, when both the settlers and the rats, dogs and pigs they introduced found Hawai‘i’s flightless birds easy prey. The second, far more extensive wave followed in the 1800s when immigrants from Europe, Asia and the Americas landed—along with the rats, cats, goats, cattle, sheep, pigs, deer, disease-carrying mosquitoes and other nonnative species they purposefully or heedlessly brought along.
The loss of wildlife that followed has been stunning. The most spectacular, perhaps, has been the extinction of more than half of some 107 endemic bird species. Still hanging on, Hawai‘i’s only two existing native land mammals—the Hawaiian hoary bat and Hawaiian monk seal—are both listed as endangered.
“Hawai‘i genuinely epitomizes the environmental problems facing our planet,” says biologist
Bruce Stein, NWF’s associate vice president for conservation science. “It has lost so much habitat, been so dramatically hit by invasive species and now faces the effects of climate change. It challenges us to answer how we’re going to respond to these three threats worldwide.”
A massive pineapple plantation dominates a landscape on the island of Maui. Starting in the mid-19th century, development of pineapple and sugar plantations destroyed some 250,000 acres of lowland Hawaiian habitat.
Large-scale habitat loss began between the mid-19th and mid-20th centuries, when development of sugar and pineapple plantations destroyed about 250,000 acres of lowland habitat, including land that long had been managed sustainably by native Hawaiian farmers. These massive plantations wreaked further havoc by draining surrounding streams and watersheds. At the same time, cattle, sheep and goat ranching were razing large swaths of the islands’ cooler, upland forests.
Today the last of the major plantations are closing down, as are many ranches. Habitat loss continues, however, driven largely by invasive species. Outside of fenced refuges, introduced game animals and the feral descendants of livestock destroy what remains of Hawaiian forests, while invasive predators such as rats, mongooses and cats kill off native wildlife.
Thornless berry bushes, nonstinging nettles, spineless acacia and scentless mints are just a few of the defenseless plants lost to browsing by nonnative hoofed mammals. Likewise, introduced cattle, pigs and goats drove to extinction many species of endemic flowering lobeliads—and with them many of the endemic Hawaiian honeycreepers whose long, curved bills evolved to fit the plants’ elaborate blooms. After being decimated by human hunting, the Laysan rail—an easy-to-catch bird native to the northern Hawaiian atoll of Laysan—disappeared completely after its habitat was destroyed by rabbits introduced in the early 20th century.
In a shot set up to show what happens in the wild—but rarely caught on film—a nonnative rat (left) gobbles bird eggs in a Hawaiian forest. While rats and other invasive predators kill off native wildlife, introduced game animals and the feral descendants of livestock, including pigs (right), decimate forests and other habitat.
Forest on the Rebound
In a handful of places, state and federal agencies have painstakingly restored native landscapes decimated by nonnative species. On the Big Island of Hawai‘i, for example, Hakalau Forest National Wildlife Refuge epitomizes “the kind of habitat restoration that is possible with the labor-intensive work of replanting as well as removing and fencing out invasive animals,” says retired refuge biologist
Jack Jeffrey. When restoration began three decades ago, Hakalau Forest was overrun by pigs and cattle that had trampled and browsed its understory plants and killed native trees by girdling their bark.
The federal government established the refuge in 1985 to protect 11 Hawaiian bird species, mostly endangered, in one of the island’s last large remnants of upland, old-growth rain forest. During the next two decades, staff and volunteers expanded this forest by about 5,000 acres.
Some of the most extensive replantings include thousands of endangered lobeliads. Today these flowering shrubs help support one of the state’s largest populations of ‘i‘iwi, a crimson honeycreeper whose long, sickle-shaped bill perfectly matches the plants’ tubular blossoms. When an ‘i‘iwi reaches through a flower to get nectar, the bird picks up pollen on its forehead and transfers the pollen to the next blossom it visits. Meanwhile, another native bird, the ‘ōma‘o, has returned to Hakalau Forest to eat the shrubs’ berries, in the process distributing seeds so new plants can begin to germinate.
But the intensive work of fencing out invasive animals can leave even the best-managed refuge vulnerable to funding shortfalls—including those spawned by recent federal cutbacks throughout the refuge system. “When I retired in 2008, the refuge had 14,000 acres of forest pig-free or close to it,” says Jeffrey, who continues to volunteer at Hakalau Forest. “Maintaining that means 63 miles of fence must be inspected monthly because all it takes is one tree fall to allow a pregnant sow to get in.” Within a year, he adds, that sow’s offspring can produce close to 100 forest-damaging pigs.
Recently, Jeffrey came across a sign that refuge staff is having trouble keeping up with fence inspections: a several-hundred-acre area where many trees and shrubs from 25 years of forest regeneration had been lost to pigs gnawing the trees’ bark and rooting out their seedlings. It was a heartbreaking sight, but such losses have inspired a promising campaign for a private endowment to fund fence maintenance and control future incursions by pigs and cattle.
Hawaiian honeycreepers, including the 'i'iwi (right) and endangered ‘ākohekohe (left) are among birds hit hardest by avian pox and malaria carried to the islands by nonnative mosquitoes. But in a good-news story, this 'i'iwi returned to one forest after biologists replanted the native lobeliad (above, right) the bird feeds on and pollinates.
The Climate Connection
Just as invasive species play an outsized role in Hawaiian habitat loss, they loom large among the threats posed by
climate change. Chief among these threats is the warmth-fueled spread of introduced mosquitoes
carrying nonnative—and deadly—plagues of bird pox and avian malaria. Hawaiian honeycreepers have been among the species hardest hit, particularly the ‘i‘iwi and the endangered ‘ākohekohe, ‘akeke‘e and ‘akikiki. Today these colorful birds are rarely found outside high-elevation forests where cooler temperatures have limited mosquito numbers and slowed the spread of avian malaria and pox.
But according to research published last October in the journal
PLOS ONE, a warming climate is likely to shrink—by more than half—the size of these remaining havens by the end of this century. Some forest birds may lose 90 percent or more of their remaining habitat to changes brought about by global warming. “It doesn’t bode well for the Hawaiian birds now restricted to the highest elevations,” warns wildlife disease specialist
Dennis LaPointe of the U.S. Geological Survey’s Pacific Island Ecosystems Research Center. “In laboratory tests, avian malaria has a 90 percent mortality rate in the ‘i‘iwi.” The death rate is somewhat lower, but still above 60 percent, for other Hawaiian honeycreepers.
Research by LaPointe and his colleagues also suggests that, in some areas, more frequent droughts are increasing populations of disease-carrying mosquitoes. That may seem counterintuitive, but in these areas, the insects breed primarily in streamside pools and pitted rocks. Normally, frequent rains and high waters flush out wet spots before mosquito larvae have time to mature into adults. But with warmer and drier conditions, the pools can remain stagnant longer and the larvae mature faster, he says.
Despite such grim news, Hannah Kihalani Springer remains optimistic. At her home on the slopes of the volcano Hualālai, she squints as a hole opens in the cloud bank, providing a glimpse of restored forest on a distant hillside. “Just as generations of our family have been involved in this forest’s restoration, we know that generations after us will remain involved in its management,” she says. Perhaps it’s this kind of intimate and enduring commitment to the environment, she muses, that the Hawaiian people can offer a planet at the crossroads.
Exquisite—and Imperiled
A snail in the genusAchatinella grazes on a leaf on the island of O‘ahu. Of 99 species of Hawaiian tree snail known to science, only about 20 survive. These long-lived, slow-reproducing animals are now restricted to patches of high-elevation forest, where conservationists hope to save them by trapping and fencing out the rats, pigs, chameleons and nonnative predatory snails that devour the native mollusks.
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