Published September 2004

Invasive Species

Homeland defense takes on a new meaning when you’re battling invasive species

by Kristen K. C. Bonilla

Hawaiʻi’s lush green lands, fresh air and pristine waters attract more than six million visitors per year.

Some stay and become an integral part of the economy and society. Other visitors slip in quietly, even accidentally. Some find the environment perfectly suited for their survival and put down roots, literally and figuratively.

Far from benign, these residents cause millions of dollars in crop losses, endanger native species, destroy native forests and spread disease.

No wonder they’re called invasive species.

Miconia, coqui frogs and West Nile virus are just the beginning. They and less well-known invaders threaten Hawaiʻi’ ecosystems, economy and, ultimately, the quality of life for residents and visitors.

A united front

Government agencies and grassroots organizations have united to take the offensive in the invasive species battle, and University of Hawaiʻi scientists and students play a crucial role in the cooperative effort.

Why? Mānoa conservation biologist Kenneth Kaneshiro explains: "All alien species have potentially significant direct and indirect impacts on our watershed ecosystem, and water is a very limiting commodity in an island ecosystem. Species such as mosquitoes, ants, houseflies, etc. all have health implications. The medfly, oriental fruit fly and other pest species have an impact on the agro-industry and economy."

When watercress on Oʻahu farms began dying, College of Tropical Agriculture and Human Resources staff traced the culprit to a leafhopper and the aster yellows phytoplasma it harbored—both unwelcome newcomers to Hawaiʻi�and began working on counter measures. Another CTAHR group is part of a government and community coalition working to contain the troublesome coqui frog through public education and humane control methods.

Mānoa botanist Celia Smith and biologist Cynthia Hunter are among those working to keep alien algae from taking over Waikīkī’s reefs. "Alien species are the most imminent threat to Hawaiʻi’s coral reefs," says Hunter, who is looking at a native sea urchin as a possible biocontrol agent under a Hawaiʻi Coral Reef Initiative grant.

Hunter and Smith work with The Nature Conservancy and other agencies to coordinate nearly 100 volunteers who gather to strip seaweed from the reef. Every few months they collect bag after bag, up to six or seven tons per session.

"It is an absolute disaster underwater in Waikīkī in terms of the health of the ecosystem," says Smith. "Yet it’s remarkable how this invasion in the ocean goes unnoticed, making the knowledge the university is raising among the community about this issue so important."

Part of the challenge is that some algae grow from a piece as small as a bite taken by a fish and spit out, making cleanup a temporary measure at best. Jennifer Smith began working on the problem as a graduate student and is now a junior researcher with seven years experience in the field. She is helping evaluate an underwater suction device purchased by The Nature Conservancy to "vacuum" seaweed off of the reef.

"Initial trials have begun but research is still underway," she says. "We have made significant headway in understanding the factors that allow invasive seaweeds to be so successful on Hawaiʻi’s reefs."

Student soldiers

Other graduate students contribute with research that identifies alien species, gauges their impact on native ecosystems and develops strategies for controlling them. Many of the 98 students in the Ecology, Evolution and Conservation Biology interdisciplinary graduate program—which draws some of the best candidates in biological sciences from across the country—focus their research on invasive issues and species, says Kaneshiro, founding chair.

Even undergraduates and non-science majors get into the act. Through a three-year-old service-learning eco-adventure program, UH Hilo students tackle land-based invaders. During the 2004 spring break, 36 students spent four days with Break Thru Adventures, clearing strawberry guava, kāhili ginger, karakanut, blackberry, Japanese honeysuckle, silk oak, eucalyptus, bushbeardgrass and other invasive species from more than 10 acres of land across the state.

"We hope to have 72 students in 2005 and to have students from other campuses involved," says program advisor Timothy Kane. An EECB student even involved K-12 students in setting and monitoring stations at homes and schoolyards that detected an invasive ant species in Hilo, allowing the Department of Agriculture to eradicate it before it could spread.

Committees that work

One of the major UH players is the Pacific Cooperative Studies Unit. The name is the key, says David Duffy, PCSU unit leader and Mānoa botany professor. "Everything is cooperative with what we do." Involved in more than 100 projects across the state, the unit provides administrative structure and personnel management so grassroots organizations and partnerships can work together to combat invasive species.

One PCSU-supported venture is the Coordinating Group on Alien Pest Species, formed in 1995 to bring agencies and organizations together to work on prevention and early detection/rapid response as well as a third, less preferred, approach—ongoing control of existing pests. If CGAPS represents the generals, immersed in policy and strategy, its platoons are grassroots partnerships called invasive species committees.

The committees have formed on an island-by-island basis, bringing government agencies, non-profit organizations, private landholders and concerned individuals together as early detection and rapid response teams. Committees on the Big Island, Maui, Molokaʻi, Oʻahu and Kauaʻi identify particular threats to their island and prioritize efforts to minimize or eliminate negative impacts.

On Kauaʻi, for example, the invasive species committee prevented the establishment of wild rabbit populations by capturing 13 rabbits descended from escaped or released pets. On Molokaʻi, one paid field person backed by volunteers has prevented the slumbers of island residents from being interrupted by the infamous high-pitched shrill of the coqui frog. The committee’s work has also kept the island free from established populations of miconia and fountain grass.

Battle for Maui

Randy Bartlett (BA ’86 Mānoa) chairs the Maui Invasive Species Committee. Involved in this type of work since he was a summer volunteer at Haleakalā National Park in 1985, he is now the Puʻu Kukui Preserve supervisor for Maui Pineapple Company.

"What interests me is keeping native Hawaiian species alive and healthy in their unique, native habitats and ecosystems so that future generations of Hawaiʻi keiki and malihini can enjoy their beauty," he says.

Maui’s committee was the first to form. Since hiring it’s first staff member in late 1999, it has made progress on pampas and fountain grasses, conducting aerial and ground surveys over thousands of acres and eliminating more than 3,000 plants. It has successfully controlled all populations of Jerusalem thorn and Indian rhododendron, a plant in the same family as miconia.

"Unfortunately there’s not enough money to go after everything, so the committees target species that pose the biggest danger yet still are considered to be eradicable," says CGAPS Public Information Officer Christy Martin.

The green cancer

The exception is miconia. It was introduced to Hawaiʻi in 1961 at Wahiawā Botanical Garden and carried by plant enthusiasts to other islands. In the early 1980s, resource managers discovered that it had spread over thousands of acres on the Big Island and Maui.

No agency in the state had the funding or ability to respond, so the infestations expanded year after year. If left to spread as it did in Tahiti, it will cause the extinction of numerous native species and severely impact watersheds statewide. Millions of dollars are now spent on control efforts.

Because other plant and animal species could be just as damaging, CGAPS facilitates funding for field crews, equipment and helicopter time that invasive species committees use to survey and control species. They have covered more than 240,000 acres of land statewide over the last four years. "If we catch things early, that would be so much more beneficial," Martin says.

Identifying the enemy

Media turned out in droves to cover the dramatic 2003 assault on Salvinia molesta, the "green monster" choking Oʻahu’s Lake Wilson, but it could have been a non-story. "Records of salvinia were found in the early 1990s, but no one was doing early detection and rapid response measures then," Martin says.

A tool like the Weed Risk Assessment system could have helped. Modified from an Australian system by Mānoa Professor of Botany Curtis Daehler, it identifies potential invaders at the border. The assessment uses a series of 49 questions to screen and score prospective plant imports. Plants scoring higher than 6 are considered a risk for becoming invasive if planted in Hawaiʻi. Miconia rates a severe weed rating of 14. Salvinia scores a 26. Officials hope use of the system will help prevent another such pest from becoming established in the islands.

Zoology graduate student Eric Conklin’s work could provide the basis for a similar assessment tool for marine plants. Conklin looks at the interaction between native and introduced marine algae and herbivorous coral reef fishes.

The worst invaders aren’t the fastest growers so much as the ones the fish find least tasty, he’s found. Gauging fish reaction to new species could provide clues about which are likely to become major threats, allowing officials to target efforts where they can provide the most impact.

Prevention is the most economical and effective measure for protecting Hawaiʻi. Public education and community outreach efforts are essential because invasive species are not top-of-mind concerns of Hawaiʻi residents. According to a focus group study conducted for CGAPS, few residents know much about how invasive species affect the natural environment and the health of the human population.

"We need greater vigilance throughout the state. Just because the situation is bad doesn’t mean we can’t have an impact," says Celia Smith.

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The invasion of Palmyra

Palmyra is a tiny equatorial atoll about 960 miles south of Honolulu owned by The Nature Conservancy, which is working with the U.S. Fish and Wildlife Service and Gordon and Betty Moore Foundation to establish a National Wildlife Refuge and research field station there.

Hundreds of seabirds nest or roost among the atoll’s remarkable Pisonia trees, their guano washed by drenching, near-daily rains into the seawater. Alien ants were noticeable when Mānoa conservation biologist Kenneth Kaneshiro first observed the thick, lush Pisonia rainforest in May 2002 as interim director of the six-institution consortium working to create the field station. He returned 10 months later to discover the trees were heavily infested with two species of scale insects tended by the ants. By June 2003, there were large gaps in the forest where trees, defoliated by the scale, had died.

"We might lose this important component of the atoll within a couple of years if something is not done to control the ants and scale infestations," Kaneshiro says. "If the forest is lost, we will start to lose the birds that roost and nest on these trees, which will probably mean less nutrients that leach back into the coral reef ecosystem, which may in turn have an impact not only on the biological diversity but also on the sustainability of the marine ecosystem." The loss would be significant, he says. Uninhabited except by military personnel during World War II, Palmyra represents one of the most pristine marine ecosystems in the Pacific and a microcosm of Hawaiʻi’s ahupuaʻa land-sea nutrient cycle.

What you can do

The Coordinating Group on Alien Pest Species launched its second "Silent Invaders" public education campaign in 2004. In short, they urge—

Don’t Pack a Pest: Declare or leave behind animals and uninspected produce, soil and commodities that can bring unwelcome hitchhikers.

Don’t Plant a Pest: Ask your landscaper, nursery or garden shop for species deemed non-invasive on the Weed Risk Assessment system.

Report a Pest: Call the Hawaiʻi Department of Agriculture pest hotline, 808 586-7378, as soon as possible after a sighting.

Kristen K. C. Bonilla is an External Affairs and University Relations public information officer.

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