BIO-CONTROL THE LAST RESORT FOR HAWAII’S PLANTS

By Valerie Monson

WAILUKU, Maui (The Maui News, May 29) – The last resort has suddenly become the only hope.

"The introduction of new species to Hawaii is the last thing scientists want to do," said research biologist Art Medeiros as he stood nearly swallowed up in a sea of spreading kahili ginger that has slowly been strangling sections of the Makawao Forest Reserve. "But we’re in a corner. With careful testing, there is a way out, there is a way for Hawaiian forests to live, maybe not in pristine form, but with all the native players present."

The battle against some of the most destructive invasive species in Hawaii might be won only with the help of some unexpected ammunition: more invasive species.

As Medeiros frets over the ginger in the forest, Ulupalakua Ranch President Sumner Erdman rides through a pasture he can barely use because fireweed has raged across it like a five-alarm blaze and now intrudes on thousands of acres that were once blanketed in thick grasses.

The fireweed, a native of Africa that may have been introduced in contaminated grass seed, is toxic to cattle and horses. It was first sighted on Maui in 1997 along the Pukalani bypass.

The problem has gotten so severe for cattle operations that Erdman and his colleagues at Haleakala, Hana and Kaupo ranches have joined forces with Maui County and the state Department of Agriculture in financing a research project to bring insects from Africa that would slow the fireweed before the pastures are completely overtaken.

"The part that’s the toughest for people to grasp is that the species we’re trying to fight are introduced species that have no natural predators here and so they go rampant, they go wild," said Erdman.

Of the thousands of plants introduced to Hawaii, only a handful have gone on to become superweeds, terrorists that take over forests and pastures. For years, biologists and environmentalists have concentrated on tediously removing large populations by hand or by applying poisons. But as they find themselves unable to keep up with these prolific invaders, many believe that drastic steps are needed to keep the islands from losing their natural identity and native biological resources.

More and more, experts in the field find themselves looking at biocontrol – the release of a new species to impede another – as the key to giving Hawaii’s forests a chance against these plants that are spreading with a tenacity rivaling that of a science fiction invader.

Medeiros, who has dedicated his career to restoring native ecosystems around Maui, would seem to be the least likely person to suggest bringing in more foreign species. The island is already reeling from other species imported with the intention of making Hawaii a better place, from the mongoose to miconia.

"It’s a dangerous subject, I know," said Medeiros. "But so is the consequence of doing nothing."

Already, after years of experiments, a fungus has been released to attack miconia, often referred to as "the green cancer" and another to hamper clidemia, a shrub that like miconia will displace native forest plants. Officials also are considering the release of a beetle that could throttle tibouchina, a colorful relative of clidemia, as well as two insects – a fly and a moth – to put the brakes on fireweed. A scale insect being tested in a Big Island lab could deter strawberry guava.

Perhaps the most surprising aspect of it all is that environmentalists – those who have pushed for strict quarantine laws to inspect incoming cargo at the airport and harbor to keep out new pests – have become some of the most ardent proponents of biocontrol.

"I’m very pleased to see the tide turning," said Ken Teramoto, biocontrol section chief at the state Department of Agriculture. "At one time, the naturalists were totally against us because they saw us as just introducing invasive species. We were being criticized all through the 1970s, but about 10 years ago, the tide started to turn. They were seeing how serious some of these invasive species were."

Bishop Museum entomologist Frank Howarth has witnessed the destruction of native forest by superweeds but still worries that biocontrol is too often seen as a magic potion.

"People are enamored by the potential power of biocontrol," said Howarth. "In fact, biocontrol is the most powerful tool in the pest-control arsenal, which means it should have limited use. Biocontrol is well-named as it can not only control the pest but also the biology of the region where the agent is introduced."

Biocontrol of plants in Hawaii is nothing new – the vadalia beetle was released in 1890 to inhibit a scale that attacked citrus – but the method has remained in the background mostly because of the image conjured from the disastrous story of the mongoose and the rat.

"Everybody says ’You’re gonna bring in something else? Don’t you remember the mongoose?’ " said Tracy Johnson, research entomologist for the U.S. Forest Service in Hilo.

Her job is to conduct exhaustive studies to determine that predatory pests pose no threat to native species or commercial crops before they are approved for release.

"People are very skeptical about bringing something new in."

From 1902 to 1999, 21 species of invasive plants were targeted for classic biocontrol in Hawaii, according to Teramoto. A total of 84 species of potential agents were released, with 60 now established: 55 insects, one mite and four fungi. The last biocontrol agents approved for release six years ago by the state Board of Agriculture were two insects aimed at attacking ivy gourd.

East Maui photographer and farmer Masako Cordray has devoted much of her time urging tougher quarantine regulations to keep destructive pests from entering Hawaii in the first place. Although she has the utmost confidence in Medeiros, the very talk of biocontrol makes her nervous.

"Anything that comes into Hawaii will have an impact on nature," said Cordray. "We have to be serious, thoughtful, deliberate and smart. I’m not suspicious, I’m frightened by the seriousness of this, by the fact that we’re in a situation where we have to consider these far-reaching actions.

"It should make us all pause. Why are we in this predicament?"

The mongoose might be Hawaii’s most well-known example of how a perceived solution can go terribly wrong. Hoping to control the rat problem, Big Island sugar plantation officials ordered a shipment of mongoose from the West Indies in 1883 despite at least one warning that more forethought should be given before releasing them.

The mongoose, which are active during the day, were little threat to nocturnal rats, but they did prey on ground-dwelling birds such as the native nene. Since the mongoose spread to all of the major islands (except Kauai), biocontrol – whether for plants or animals – has been "couched in negativity," said research biologist Lloyd Loope.

"Hopefully, we’ve learned something since 1883," said Loope. "Biocontrol is the only hope in the long run for a place like Hawaii where invasive species has become such a threat to the native biota."

Teya Penniman, manager of the Maui Invasive Species Committee, wasn’t sure what to think when she first heard about it.

"This has been an education for me," said Penniman. "I’m definitely someone who errs on the side of caution. Are we opening a Pandora’s box by looking into biocontrol? You can point to the spectacular failures of the past, but these failures occurred years ago, before we had such a rigorous approach that’s used by biocontrol agents now."

Medeiros said he believes the tight regulations governing biocontrol make it a risk worth taking.

"The native forest is in serious trouble," said Medeiros. "If we were driving a car in the same situation, there would be a red light blinking on the front panel and something would be smelling. If nothing happens to slow down these weeds, in 100, 200 or 300 years, they’ll be occupying their full range in the forest, with heavy implications."

Although complete studies have yet to be done, Medeiros and others fear that the spread of the superweeds through the native forest will impact the watershed, speed erosion and send silty runoff into the nearshore waters and onto the reefs.

Species like clidemia and tibouchina are not as effective at trapping rainfall as the native ferns they displace in the forest. When they take over a slope, rainfall does not percolate into the ground as well, running off instead straight to the ocean.

"We know the native Hawaiian ecosystem is a perfect sponge that produces clean water," he said. "I don’t think we fully know the implications, but why mess with perfection?"

Medeiros recently returned from Brazil, home to some of the worst of Maui’s invasive plants: miconia, Christmasberry, strawberry guava, tibouchina and clidemia. Oddly enough, those plants in their native surroundings look nothing like the megaweeds they’ve become in the islands, mainly because, in their native habitat, they have natural predators to keep them in check.

Those predators are what lured Medeiros to South America. For years, Hawaii has developed a strong working relationship with universities in Brazil to locate insects, fungi or other pathogens that attack the plants in question. Once identified, the predators are tested in their native countries and, if they pass muster, are then shipped to quarantine labs on Oahu or the Big Island, where they undergo years of scrutiny to ensure that they won’t harm native plants, related plants or commercial crops.

Medeiros said the insects sought are specific "like computers" so they target only certain species instead of attacking at random.

The required length of the testing can sometimes be frustrating to scientists as the targeted invasive species continue to multiply in the wild.

"At times the rules appear overly stifling, but they are necessary to prevent abuse and to adequately demonstrate the safety of the proposal," wrote Clifford Smith, the University of Hawaii retired entomology professor who pioneered the bond with Brazil. "It is tragic that such rules are not applied to the importation of alien plants in the first place."

That’s how Hawaii got on this bizarre merry-go-round. The first known instance of biocontrol took place in 1865, when the myna bird was brought in to eat army worms. But myna are omnivorous, eating fruits and seeds as well as worms, and spread lantana seeds in their droppings. So, in 1902, a succession of 25 insects began to be released to impede lantana, another plant originally brought in as a colorful ornamental.

While lantana still thrive, that particular disbursement of insects actually helped control the plants, which can grow 6 feet tall. The lantana story also demonstrates the limited capability of biocontrol: it’s not a cure-all, only an added weapon.

"Biocontrol does not cause extinction," emphasized Teramoto. "It reduces the population density or favorite hosts to manageable densities. You still see lantana here, but it’s not everywhere."

With tenacious weeds, Tracy Johnson said, biocontrol has become "the only thing that will put a dent in them."

"It’s very helpful to have a tool that gives you an edge to slow down the spread," he said.

Steven Lee Montgomery, a longtime entomologist and president of the Conservation Council of Hawaii, echoes those comments.

"There is no alternative than to reestablish that enemy in this new range of these alien invaders," said Montgomery. "Every year the (testing) process becomes more environmentally aware and more restrictive. I’m impressed with the safeguards we now have in place."

Howarth thinks a few alien weeds that have no close relatives in Hawaii, like miconia, might be suitable for biocontrol "with adequate research," but he remains cautious with so many unknown risks at stake. He’s concerned that only the feeding stage of new species is usually tested in quarantine.

"Often we have no idea what other roles the agent might play in the ecosystem," he said. "For example, the agent might be highly effective as a weed biocontrol agent as larvae, but the adults may pollinate other weeds, disperse harmful agents or serve as a food resource for other invaders."

Sheila Conant, professor and chairwoman of the Department of Zoology at the University of Hawaii at Manoa, doesn’t think that biocontrol should be used for every little problem weed, either, but sees it as the only option to get a handle on the major invaders.

"There’s no way we’re ever going to control things like miconia if we just continue to send out Sierra Club volunteers and Boy Scouts with machetes or helicopters with poisons," said Conant. "We have to decide if we’re going to accept this or if we’re going to take a risk."

Erdman and the other ranchers are keeping their fingers crossed that they’ll have some new tools in fighting fireweed, a stubborn shrub with yellow flowers that’s amazingly profuse: one plant alone can produce 30,000 seeds. Teramoto said that a 1999 trip to South Africa and Madagascar, both home to fireweed, has resulted in two insects that are close to being approved for release.

The journey has been a long and complicated one. A state biologist was sent to Africa, where he collected about 14 different species that appeared to attack the weed. Once in the quarantine lab in Honolulu, attempts were made to colonize the insects and begin testing them against native plants or other plants that might be in the same family as fireweed. Some insects failed to colonize, others attacked something in addition to fireweed and still others simply weren’t effective at all. That left two – a moth that defoliates fireweed and a fly that feeds on the flower head.

Six years later, a proposal is finally being written up to get the moth out of quarantine, said Teramoto; the fly could be approved for release by the end of the year.

Another trip to South Africa and Madagascar came up with another moth whose larvae appear to be "a more voracious" feeder.

"But for this new one, it will be at least four years to get new data before it can be released," said Teramoto.

Erdman has faith in biocontrol because he knows the success that occurred more than 50 years ago with pamakani, an invasive semi-woody shrub that had overrun the Ulupalakua pastures and was making the horses sick. (Pamakani was given its Hawaiian name because its leaves resemble a native plant; the shrub, however, came from Mexico).

David T. Fleming, the agronomist who converted the former Honolua Ranch to a pineapple plantation, introduced a wasp that diminished the pamakani so much that Edward Baldwin, ranch manager at the time, gave him 17 prime acres at Puu Mahoe as a gift of gratitude.

"It was fantastic, it reduced the pamakani to more than manageable," said Erdman, who nowadays has to keep a few of the offending plants growing to maintain the biocontrol population.

Unfortunately, pretty names associated with some particularly nasty plants gives the public the wrong impression about their true nature. Montgomery said kahili ginger, a relatively recent import from Asia, got its Hawaiian-sounding name from "a nursery operator trying to increase sales."

In reality, the ginger spreads so fast that Montgomery says it’s "irresponsible" to even allow it to pass quarantine.

Any effort to control ginger with biocontrol will most likely prompt protests from those who who love the plant – "moral quandaries," as Medeiros puts it. Howarth correctly notes that "one man’s weed can be another’s livelihood."

Another dilemma centers around an insect that attacks Christmasberry, but also defoliates neneleau, a small native Hawaiian tree also known as Hawaiian sumac. The bug attacked no other native plants, but all testing was dropped in the islands to protect the neneleau.

"I was willing to make a deal," said Medeiros. "Why don’t we give up neneleau? We’re going to lose an entire ecosystem."

Others didn’t agree, so experiments were shelved. However, the insect continues to be tested in Florida, where Christmasberry is also a problem, meaning Hawaii officials will watch from afar. In addition, Florida has caught the attention of biologists with its new, multimillion-dollar quarantine labs for conducting the tests while Hawaii struggles along with three research facilities around the state that Johnson describes as "decrepit."

"This is a need the state is going to have to address," said Johnson, who estimated that it costs $1 million for about five years of research and testing on one bug or fungus that would target an individual weed.

For years, millions of dollars have been invested, mostly in the form of human labor, in attempting to control the superweeds. The Hawaii Invasive Species Committee has a 2004-05 budget of $4 million, and the same amount has been approved for the next fiscal year. Haleakala National Park has allotted $560,000 this year to battle miconia, including $50,000 for biocontrol.

Maui County has budgeted $850,000 for everything from education to projects targeting certain species such as fireweed, miconia, banana bunchy top virus and coqui frogs.

Other costs associated with invasive species may never be known. Erdman said it’s impossible to put a monetary figure on something like the loss of pastureland.

Montgomery speculates that, in the long run, that biocontrol will prove to be a better investment in the battle against the superweeds.

"The evidence is overwhelming," he said. "It’s much more cost-effective than to spend $1 million on field crews."

Howarth said if biocontrol is to proceed, funds and resources must be committed for long-term monitoring of the results, as well.

"For most past projects, we have no idea what the agent did, and claims for success are based solely on hearsay," he said. "We have just a handful of studies where people have actually followed what happened."

Howarth still believes Hawaii needs to concentrate on beefing up its quarantine system to make any biocontrol effort worthwhile.

"It makes no sense to biocontrol a pest which is then replaced by another, which is then biocontrolled to again be replaced by another, ad absurdum," he said.

Medeiros agrees. He emphasizes that biocontrol is one of only four steps that must be in place to sufficiently reduce superweeds and allow the native forests to rejuvenate. Just as crucial to the effort, he said, are strict quarantine regulations, the various invasive species committees to rein in existing problems or emergency outbreaks, and traditional management such as building fences and getting rid of feral cattle.

All together, it might just work and save an ecosystem.

"Are we ever going to get rid of these weeds? Clearly, the answer is no," said Medeiros. "We need to make them less super plants. And for some of these, there’s no other option but biocontrol."

May 30, 2005

The Maui News: www.mauinews.com

 

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