For three hot and sticky days bridging the months of July and August, the collective knowledge of more than a thousand of the world’s foremost experts in conservation biology was focused in the meeting rooms and conference halls of the University of Hawai`i at Hilo. Some 1,300 scientists representing 42 nations attended the 15th annual meeting of the Society for Conservation Biology.
The theme this year was “Ecological Lessons from Islands.”
In talk after talk, session after session, Hawai`i and its myriad problems and opportunities were placed in a global context. Resource managers working in the state were able to share ideas and techniques with their counterparts from as far away as South Africa.
Three writers for Environment Hawai`i attempted to cover the event, during which as many as seven different talks might be occurring at any given time. We’ll publish highlights in this and coming months.
Evolution Under Our Noses
Picture this: even as more than a thousand biologists were discussing how to save the incredible diversity of species that have evolved, especially in isolated island settings, the Hawai`i Board of Education was giving serious consideration to requiring science teachers to tell their pupils that evolution is just one of several, equally valid theories concerning the origin of life. Although the word “creationism” was not mentioned in the proposal before the board, it was certainly conspicuous by its absence.
The tempest – mercifully short-lived – probably did little to elevate the visiting scientists’ view of the state of public education in Hawai`i.
One of the first speakers to get in a dig at the proposal was Hawai`i native Peter Vitousek, professor of population at Stanford University. In one of the keynote talks, Vitousek took note of the comments of Denise Matsumoto, a BOE member who had commented that there was no evidence to support the theory of evolution. Vitousek seemed incredulous that anyone could hold such a view “here, of all places, where concrete evidence of evolution is all around us.”
Indeed, presentation after presentation served to underscore evolutionary theory and its corollaries.
Consider just the case of the tetragnathid spiders. More than 50 species of these long-jawed spiders have been identified in Hawai`i, with many more awaiting formal description. Amy Vandergast, a doctoral student at the University of California at Berkeley, has hypothesized that those living in the interior of a forested kipuka (vegetated land surrounded by lava flows) would be more genetically isolated than would spiders of the same species that live in continuously forested areas.
Vandergast’s research bore out her hypothesis. Only 150 years after the forest where she studied the spiders was fragmented by lava flows, the spiders living in the kipukas are starting to differ genetically from their counterparts in the larger forests. “There’s little new input” of genes from outside the kipukas, Vandergast said. Inside the kipukas, “each population is on its own evolutionary path” – proof positive that “evolution of new species could happen,” she said. “It’s like each population in a kipuka is holding a ticket in the evolutionary lottery. Most likely, the genetic changes that occur will be minor, but there is a very slight chance that one of these populations is holding the winning ticket, and the selective conditions will be right for the evolution of a new species.”
Sheila Conant, an expert on Hawaiian birds and chair of the Zoology Department of the University of Hawai`i-Manoa, described Hawai`i as “one of the most wonderful evolutionary laboratories available.”
“We can study evolution in Hawai`i at many different scales. There’s the time series of islands that have popped up over millions of years. We can look at how things speciate across islands and within islands. We can look at the microevolutionary processes as well as macro-speciation events.”
“Evolution,” she told Environment Hawai`i, “is simply fundamental to understanding biology.” — Patricia Tummons
Sir Robert Says: ‘Study the Grotty Things’
It was standing room only in the University of Hawai`I at Hilo Theatre when Sir Robert May, president of Great Britain’s Royal Society and chief scientific adviser to the British government, gave the plenary address that launched the meeting. May, a mathematical ecologist known for his accomplishments in the field of chaos theory, has used mathematical modeling to establish that, compared to historic patterns, the present risk of species extinctions is unusually high.
Extinction was the subject of May’s address, and he asked the audience an uncomfortable question: Are conservation biologists putting their personal interests ahead of pressing conservation needs? Having surveyed recent issues of the Society’s journal, Conservation Biology, May pointed out that of 144 papers, 60 percent deal with birds, mammals, and other vertebrates while only 20 percent presented research on plants and a mere 10 percent addressed research on invertebrates.
May chided his audience. “It’s much more glamorous to look at beautiful birds than at grotty things through a microscope,” he said. “But if you are interested in how ecosystems came to be the way they are, and how they function, you can learn much more from soil microorganisms than from charismatic vertebrates.” May urged the assembled conservation biologists to put the needs of the planet ahead of their own interests, saying, “We ought to reflect more on the huge duplication of effort in a field where there isn’t enough effort to begin with.” — Cynthia A. Berger
Ambassadors of Extinction
Extinctions of Hawai`i’s native species began not when Europeans arrived in the late 1700s (although the pace was certainly exacerbated after western contact), but when the islands were settled by Polynesians about 600 years earlier. Now Dr. Stephen Athens of the Honolulu-based International Archaeological Research Institute has evidence from pollen cores to that suggest human settlers didn’t have to actually live in an area for the native flora and fauna to be impacted by their presence.
Athens and colleague Jerome Ward collected sediment cores from sinkholes on O`ahu’s `Ewa plain, then examined the plant pollens preserved in each layer to identify native and introduced plants. They also looked for evidence of local human settlement, in the form of charcoal particles, which are produced by cooking fires or when vegetation is burned on cropland. The researchers found that certain forest trees were almost gone from the plain by 1000 A.D., even though the abundance of charcoal particles did not peak until around 1400 A.D.
“The forest seems to have collapsed very rapidly before the Polynesians ever lived there,” said Athens. “So it’s not that the Polynesians burned or cleared the forests. Something else was responsible for the forest decline.”
The “something else” was probably Rattus exulans, or the Polynesian rat, an accidental introduction that was brought to Hawai`i by some of the earliest Polynesian settlers. In archaeological excavations, the scientists discovered rat bones that dated to A.D. 1000. “So rats were on the `Ewa plain long before people moved there from other parts of the island,” Athens said. Like many other reports presented at the conference, Athens’ underscores the importance of the fossil record to the task of understanding what the island’s ecosystems were like before human settlement. And what’s just as important, it adds weight to the growing view that restoration of island ecosystems is a task that is practically unattainable in the presence of rats.
Recreating Eden
For most of the last three decades, Helen James of the Smithsonian Institution has looked into sinkholes, caves, and lava tubes across the Hawaiian islands. The discoveries of James and her husband, Storrs Olson, of the skeletons of long-extinct flightless birds – rails, ibises, and geese – have become famous. But at the SCB conference, James wanted to drive home a different message, one that focused not on losses, but on the potential for restoration.
By looking at the pre-human range of birds that are still existing (albeit precariously), biologists may be able to understand better the present habitat needs of those birds. Many of Hawai`i’s most imperiled birds today are found in areas that might not be optimal, while forest habitats themselves may have changed due to the disappearance of rare and extinct species.
For example, James cited the dark-rumped petrel, or `ua`u. Of all of today’s endangered species present in the fossil records, this bird had the widest range. “Imagine the nutrients they imported,” James exclaimed, as thousands of the birds flocked each evening from the ocean to their terrestrial nests. Second most abundant was the nene, whose ancient habitat included coastal as well as montane areas.
The Maui parrotbill, known now only from the wet, windward forests of Maui, used to live on the dry side of the island, as did the po`ouli. (On the subject of the prospects for restoring the po`ouli, a species whose known population consists of just three individuals, James was not optimistic: “It may be a lost cause unless we can restore the dryland habitat,” she said.)
The palila, a bird whose present range is restricted to the high slopes of Mauna Kea, inhabited lowland sites on Kaua`i and O`ahu – habitat so different from today’s that, James said, “you have to wonder: are these the same species?”
Of all the birds discussed by James, the Laysan duck may be the species where the potential for restoration is greatest. Far from being restricted only to Laysan, a small island in the Northwestern Hawaiian archipelago, the duck was present in pre-human times on all the main islands, both in upland and coastal areas. Confined today to just Laysan, James said, “the Laysan duck is a sitting duck,” vulnerable to natural disasters, such as storms, or unnatural ones, such as the introduction of predatory animals. If it could be reintroduced to protected habitats elsewhere, the bird’s chances for survival could be enhanced, at the same time that one of Hawai`i’s endemic birds, extirpated from its former range, could be restored to a portion of its original home. Among areas being considered are Eastern Island at Midway and Kaho`olawe; according to Beth Flint of the U.S. Fish and Wildlife Service, the duck cannot co-exist with any mammal (including rats), which limits options for successful reintroductions.
A similar message was delivered by David Steadman of the Florida Museum of Natural History. Before human invasion of the remote Pacific islands, some 2,000 species of flightless rails had evolved. Now barely a dozen of them survive.
The Guam rail, which is being reared in captivity for future reintroduction, faces in its home range threats from rats, brown tree snakes, and other introduced predators. Why not, then, introduce the rail onto a remote, uninhabited, predator-free island in the Northern Marianas? Steadman suggested. The climate and habitat are similar to the rails and prospects for an eventually self-sustaining population would be greater there than in its home range.
Similar opportunities exist for the Polynesian megapode and perhaps dozens of other species. By taking advantage of islands where habitat still exists, even though it may be outside the known range of an endangered species, extinctions of birds, giant tortoises, land iguanas, and other animals on oceanic islands “need not be irremediable or forever,” Steadman said.
— Patricia Tummons
Drosophila Declines
The rat took front and center stage in another presentation, this time by David Foote of the U.S, Geological Survey’s Pacific Islands Ecosystems Research Center. At Hawai`i Volcanoes National Park, Foote and his colleagues wrestle daily with the task of managing and restoring the various native species found there. Among the more difficult challenges they face is that of protecting some of the Park’s least conspicuous yet most famous natives, the picturewing Drosophila. These unusual fruit flies are known for their oddly shaped legs and mouthparts, large wings with infinitely varied markings, and their distinctive mating behaviors. Twelve picturewing species were recently proposed for listing under the Endangered Species Act.
“The forest seems to have collapsed very rapidly before the Polynesians ever lived there É so it’s not that the Polynesians burned or cleared the forests. Something else was responsible for the forest decline.” – Stephen Athens
For years, Foote has been monitoring Drosophila populations in the park – a thankless job that involves saturating bait sponges with the essence of fermenting bananas or mushrooms. Over the last three decades, some species have show alarming declines. Overall the park has lost 10 percent of its picturewings, but in certain locations, the declines are even more serious; in Ola`a Forest, for example, four out of 14 species have disappeared. This is despite the Park’s apparent success in restoring its native mesic forest.
What’s going on? Foote and his colleagues have identified two alien animals that pose particular problems for Drosophila. One is rats, which girdle and kill plants the flies rely on, such as the native lobelia Clermontia hawaiiensis. The rats also gobble up plant seeds, which slows forest regeneration.
The second is the western yellow jacket, which preys on Drosophila. An insecticide that had been under consideration for controlling yellow jackets turned out to kill Drosophila as well. To protect the park’s Drosophila, habitat restoration programs should continue, Foote says, but more effective programs to control alien invaders will also be key.
— Cynthia A. Berger
E-Rat-ication Efforts
As is evident by now, time and again, biologists at the conference identified rats as one of the most intractable threats to restoration of healthy populations of birds and plants, not only in Hawai`i, but in other island areas such as New Zealand and the Caribbean. Some scientists believe that more than 40 percent of recent bird and reptile extinctions an be attributed to rats.
As several speakers noted, rats can be and have been eradicated, at least from smaller islands. Buck Island in the U.S. Virgin Islands provides such an example. There, rats were preying on sea turtle eggs and their hatchlings. Using bait blocks containing the rat poison diphacinone, some 420 bait stations were set up across the island’s 178 acres. Within weeks, the rat population was exterminated. Nest success for the green sea turtles is up, as is the population of nesting pelicans.
Could rats be eradicated on the main Hawaiian islands? That would be difficult, but it is conceivable that in areas of prime habitat for forest birds, rat populations could be suppressed sufficiently to give the birds a break.
Earl Campbell, head of the U.S. Department of Agriculture National Wildlife Research Center field office in Hawai`i, has been working to acquire the needed approvals from the Environmental Protection Agency to broadcast diphacinone, an anticoagulant that is generally regarded as having little effect on non-target species.
— Patricia Tummons
Volume 12, Number 3 September 2001
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