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from the July/August 2000 issue of People, Land & Water, the employee news magazine of the Department of the Interior

Hawaii: A Model for Addressing Invasive Species

Lloyd Loope and Joan Canfield, USGS, Honolulu, Hawaii

image of Hawaiian Islands

Hawaiian islands like Maui are ideal invasives laboratories.

The Hawaiian Archipelago stands out as a jewel in the islands of the Central Pacific. As Mark Twain remarked in Roughing It, "They are the loveliest fleet of islands that lies anchored in any ocean."

Unfortunately, though, the loss of species in the islands has been staggering, and what remains occupies but a fraction of their historical range. Much of the loss has been due to biological invaders, which are particularly troublesome on island habitats, where native species don't have strategies to protect against non-native newcomers.

The Hawaiian Islands provide an ideal laboratory for addressing harmful invasive species problems, because invasive species are the state's dominant biological resource issue today. Hawaii's invasive species crisis affects the state's many native plants and animals, overall environmental and human health, and the viability of its tourism- and agriculture-based economy.

In fact, the brown tree snake, red imported fire ant, and the invasive plant Miconia-all of which threaten Hawaii-are among the world's most fear-inspiring non-native species; but these are just a few of the many invaders of the spectacular ecosystems of the Pacific Islands. Hawaii's problem with non-native species is the most severe of any state. Federally significant resources are at stake, including prime national park natural areas and a third of the nation's endangered species.

The gravity of Hawaii's situation has resulted in innovative approaches that have the potential to become national and global models. These islands are isolated little fortresses-surrounded by large expanses of ocean and subject to invasion primarily through human action. With rational interagency management based on good science, and with the help of informed citizens, the problem of invasive species can be effectively addressed.

Oceanic island ecosystems, such as those found in Hawaii, are very susceptible to damage caused by humans and the non-native plants and animals they bring with them. More native species have been eliminated in Hawaii than anywhere else in the United States- and in most places in the world. While habitat destruction has caused extinction and endangerment, non-native species have also contributed to major ecosystem damage and are now the main cause of loss of biological diversity in Hawaii.

Early Warning System for New Invasive

Lloyd Loope MAUI, Hawaii

USGS scientists from the Pacific Island Ecosystems Research Center are taking steps to nip in the bud new plant invasions on the island of Maui. Plans are now in place for detecting new invasive plants that are starting to spread and alerting the control crew of the Maui Invasive Species Committee-a voluntary partnership of private, government, and non-profit organizations-to remove and destroy the plants.

The 3-year project will also address more general questions of how an early warning system might work and how to pinpoint various pathways of plant invasion. Unfortunately, in Hawaii, the pathways sometimes seem to be more like superhighways. For example, seeds of infamous invasives, such as Chinese tallow and pampas grass, are readily available in Hawaii through the U.S. mail, via the Internet.

At 728 square miles, Maui is small enough to form a near-perfect laboratory for this kind of project. It is also highly susceptible to invasion by non-native species. Siting the project on Maui is further warranted by the presence of nearly 100 endangered species and a major national park (Haleakala) which is rich in native plants and animals, as well as agriculture, watershed, health, and quality-of-life concerns.

Ecologists use the term "lag phase" for a stage between the first establishment of a free-living population of a weed and the spread of that invasion to a landscape scale. The project will investigate the nature of this "lag phase" on Maui. The information gathered will help us understand this lag and also help educate the local and national public in how invasions start snowballing from the initial incoming plant or seed.

The story of how Hawaii's biota came to be sheds light on its special vulnerability to non-native plant and animal pests. The few creatures that reached Hawaii before human influence traveled over thousands of miles of open ocean by floating, being carried by the wind, or being attached to birds. The Hawaii that these plants and animals first inhabited was composed of a remarkably diverse habitat. Over time, and in near complete isolation, some 11,000 species are believed to have evolved from roughly 2,000 ancestors that arrived during a 70-million-year period. This is a rate of one successful natural colonization every 35,000 years.

In contrast, today 20 to 50 new non-native species arrive in Hawaii every single year. Few visitors realize that the lush lowland vegetation and colorful flowers they marvel at are not native to the islands but are, instead, part of a diverse collection of non-native invaders-some of which pose major threats to the integrity of Hawaii's native landscape.

Some of Hawaii's ancestral colonizing species are sources of the world's most amazing examples of adaptive radiation: Hawaiian honeycreepers, picture-winged flies, and the silversword plant group. The animals and plants of these islands are an important part of Hawaii's, America's, and the world's natural heritage, and comprise a valuable natural resource. They are much of what make up the beauty and wonder of Hawaii.

Hawaii's Coordinating Group on Alien Pest Species is taking the lead in actively dealing with statewide invasive species issues. Established in 1995, the group is an alliance of biodiversity, agriculture, health, and business interests. One of the grassroots island invasive species committees allied with the group is the Maui Invasive Species Committee, a voluntary partnership since 1991 of federal, state, county, and private entities, united to prevent new invasive pest species and to eradicate incipient infestations.

Since the 1970s, Hawaii's national parks, especially Hawaii Volcanoes and Haleakala, have led the nation in innovative management techniques to control harmful non-native species. The Northwest Hawaiian Islands National Wildlife Refuge is pioneering efforts at effective invasive species eradication in areas where the U.S. Fish and Wildlife Service manages entire islands.

There is now a major national effort-through the President's Executive Order on Invasive Species-to remedy the lack of a comprehensive U.S. approach to quarantining invasive species and preventing their establishment. This effort addresses both intentional and non-intentional pathways. This is an especially serious problem in Hawaii, and it is one for which the coordinating group is actively seeking strategies and solutions. While Hawaii has some of the best statutes and regulations for preventing the arrival of invasives, resources and enforcement authority are still lacking.

The USGS scientists from the Pacific Island Ecosystems Research Center have played a major role in providing science-based information to Interior Department and other conservation management agencies in Hawaii. USGS is a key player in the coordinating group and every island invasive committee, conducting research on non-native species and providing needed information. Examples of active USGS projects on invasive species follow.

Biological Aliens Home || Director's Message || Bugging Purple Loosestrife || Cogongrass, Chinese Tallow ||
Exotic Crayfish || Exotic Mussels || Hawaii: A Model || Leafy Spurge || Mapping Invasive Plants ||
Non-native Grasses and Fire || Pepperweed || Prescribed Fire || Saltcedar || Spring Brings Hope