Miconia wins: Experts concede Hawaii Island has lost the war against invasive plant

The problem is beyond control on Hawaii Island.

The problem is beyond control on Hawaii Island.

So says a 2017 legislative report by the Hawaii Invasive Species Council as it discusses what’s been called the worst invasive weed in the state: miconia.

Early efforts to contain the tall South American plant with giant purple-and-green leaves paved the way for the establishment of the state’s current invasive species management models. Around the state, miconia control spurs innovative ways to manage invasive plants.

Here, in the place where statewide management efforts first began, the battles will continue. But miconia has won the war.

“When we learned about miconia, it was already pretty far gone; it was pretty widespread,” said Christy Martin, public information officer for the Coordinating Group on Alien Pest Species. “It’s not going to be eradicated from the Big Island.”

“Our hope is to find biocontrols that are able to at least make the plant behave better.”

Introduced to an East Hawaii botanical garden in 1959 as an ornamental plant, miconia was a perfect storm of invasive attributes.

“The main thing is it can grow in such dense patches and create such a dark shade that it outcompetes everything else,” said Tracy Johnson, a research entomologist with the U.S. Forest Service. “There’s nothing else that can grow underneath it.”

“Even if you control the adult plants, the seed bank is just going to go on and on and on,” said Franny Kinslow Brewer, communications director for the Big Island Invasive Species Council. An adult miconia plant produces about 1 million seeds, and seeds remain viable for more than 15 years.

Animals like to eat miconia fruit, acting as seed dispersers. A single miconia plant doesn’t need any help from pollinators to reproduce.

“That’s why, if you find one plant in a remote area, it’s an extremely dangerous situation,” said James Leary, assistant specialist in invasive weed management in the University of Hawaii at Manoa’s College of Tropical Agriculture and Human Resources. “One mature plant will impact 2,000 acres of forested watershed.”

Leary works on Maui, where the miconia problem is nearing a critical point in terms of control. For the past four years, he’s targeted those single plants in hard-to-access areas, using the unconventional method of herbicide-soaked ballasts launched from a paintball gun (“It allows me to treat individual plants with surgical precision,” he said).

Leary collaborates with invasive species committees on Maui, Oahu and Kauai, but “the miconia problem on the Big Island is quite a bit different than on the other islands.”

“I think one of the cautions (is) we’re closer to ending up like the Big Island than we are to Oahu and Kauai,” he said. Pockets of miconia exist on the latter two islands, and surveys will continue as long as mature trees continue to be found.

Hawaii Island invasive specialists, meanwhile, are working to make sure the Big Island doesn’t end up like Tahiti, where miconia has displaced more than two-thirds of native forest since it was introduced in the 1930s. It’s also contributed to increased landslides — its shallow root systems make erosion more likely.

“They call it the green cancer or the velvet cancer,” Kinslow Brewer said (miconia is also known as the velvet tree). “It really just took over the forest and it created huge problems.”

After biologists from Hawaii visited Tahiti and saw what was going on, they came back and “raised the alarm,” Martin said. Miconia was declared a noxious weed in 1992.

Even then, containment efforts were slow to take root.

“One of the signs I saw for the (April) science march was ‘At the beginning of a horror film, there’s a scientist being ignored,’” Martin said. “I really feel like (miconia) is a great example of that.”

“Generally, the issue of invasive species isn’t something that was really in the public consciousness until the 1990s,” said Josh Atwood, HISC program director.

In 1996, Hawaii Island’s Melastome Action Committee formed to address miconia. In the coming years, as its focus expanded to controlling more and more species, the group would become the island’s invasive species committee.

“For us, (miconia) is the reason BIISC exists in a lot of ways,” Kinslow Brewer said. “It really got the conversation started.”

Hawaii County Councilman Aaron Chung recalled donning white hazard suits with fellow council member Julie Jacobson in the late 1990s to go on a “miconia expedition.”

“We helped to cut some of the miconia plants, and we just went … to see what the extent of the problem was and educate ourselves as to what the state was doing,” Chung said.

By 2000, a management plan had been developed for the Big Island. A miconia hotline was established and public outreach efforts ramped up. Operation Miconia involved both paid crews and volunteer efforts.

In 2001, an economic downturn resulting from a post-September-11 drop in tourism prompted Maui Sen. J. Kalani English to put forth a job-creation bill during a special session. This formed the Emergency Environmental Work Force, which dedicated a large portion of its effort to miconia control on the Big Island.

A three-and-a-half month stint in Kurtistown in 2002 “exceeded all expectations,” according to a legislative report prepared in November 2002. In six weeks, 36,872 plants were killed over 3,053 acres. An “astonishing” 280,550 plants were killed in the Onomea-Papaikou-Makai Kawainui area.

“Miconia is recognized as the first priority for control efforts by all of the ISC’s (sic) but other targets are unique to the individual islands based on their history and ecology,” the legislative report states.

HISC, the statewide interagency group that now manages grants and funding for the invididual islands’ committees, formed in 2003.

A 2007 study estimated that miconia costs about the state $672 million annually in terms of lost groundwater recharge and value of endangered species habitat.

“I think the important thing to know about miconia is it impacts you even if you don’t see it,” Atwood said. “If you’re somebody that’s living in downtown Hilo or downtown Honolulu…it still impacts you because it is displacing native plants and increasing erosion potential. All of that contributes to less healthy watersheds, less drinking water.”

Today, the Big Island’s best hope for control could come in the form of a butterfly.

Tracy Johnson, the USFS research ecologist, began working on the miconia problem in 2000, trying to find a biocontrol solution (one solution, a fungus that causes leaf spots on the plant, has not been effective in Hawaii, but does seem to work in parts of Tahiti).

Johnson, in collaboration with scientists in Costa Rica and Brazil, has considered types of weevils, gall wasps, and moths as biocontrol agents. Some of the miconia-attacking insects the field teams have found are entirely new to science, he said, and haven’t even been named yet.

The Costa Rican butterfly Euselasia chrysippe is not a newcomer, though. As a caterpillar, it feeds only on the leaves of melastomic plants like miconia. The caterpillars hatch in masses and “follow each other around and eat together,” Johnson said.

“There’s no native trees or anything of value that it would eat,” he said. “So that one looks quite good.”

State Department of Agriculture and U.S. Department of Agriculture approval would be needed to bring the butterfly into the state for biocontrol.

“We’d certainly plan for release on Maui and Hawaii Island,” Johnson said.

The question now, Martin said, is “Can we control it (miconia) long enough to find biocontrol that would work long enough?”

But given that more than two decades have passed since control efforts first began, it’s challenging to find resources to continue the long-term fight.

“I do have concerns about whether or not it will continue to be something the state Legislature prioritizes,” Atwood said.

“This is one of the scary things about working in invasive species: the Legislature gets kind of fatigued,” Kinslow Brewer said. “It gets more and more difficult to get funding for something year after year when there really isn’t an eradication…in sight. You’re then in a management and control scenario pretty much forever.”

Leary’s herbicide ballistic project received $117,212 from HISC in 2016. Johnson’s biocontrol work received $30,318. No other miconia-related projects were funded by HISC, which receives its budget from the state base budget and legislative appropriations.

“We’ve got more pressing problems now,” Chung said, citing little fire ants, coffee berry borer and rapid ohia death. “Every year it’s something else coming up. Those are the things that…we’ve got to focus on.”

Leary said his philosophy is to “work with what we’ve got and be as efficient as possible in our miconia management plan as they (the invasive species committees) become obligated to take on more problems.”

“It’s frustrating for a lot of people who worked on this for a number of years just to see it roaring back,” Kinslow Brewer said. BIISC still gets inquiries about how to control miconia plants, and a new outreach campaign is planned for later this year.

Atwood and Martin said that miconia eradication remains likely on Oahu and Kauai.

Miconia is now cited as both a cautionary tale and a learning experience. The field of invasion biology has changed considerably since campaigns first started.

“Now we have a good sense of how to determine if a plant species is likely to be invasive,” Atwood said. The Hawaii-Pacific Weed Risk Assessment test was formally implemented by HISC in 2005.

“The (BIISC) plant crew’s job is go out and get the worst of the worsts before they become miconia 50 years from now,” Kinslow Brewer said.

“We go after these really terrible plants.”

Jerusalem thorn, a plant with an even higher HPWRA score than miconia, has nearly been eradicated from Hawaii Island, she said.

“We are so much better at invasive species management in Hawaii than we were 10 years ago,” Leary said. “We’re getting smarter, we’re getting more economical — that’s probably where we can hang our hope on.”

The problem, he continued, is that “biology is still outsmarting us.”

Email Ivy Ashe at iashe@hawaiitribune-herald.com.