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Invaders Endanger Hawaiian Species HONOLULU, Hawaii, September 2, 2002 (ENS) - A snake was sighted August 27 in Honolulu on a grassy hillside near a medical center by a patient on his way to an appointment. He reported it to hospital security, who reported it to the police. Police officers surveilled the area until agriculture officials arrived. An intensive search of the area by agriculture officials failed to turn up the snake. Snakes are illegal to possess or transport in Hawaii, and violators are subject to stiff penalties, including fines of up to $200,000 and up to three years in prison.
More than a third of the species on the U.S. endangered species list inhabit the Hawaiian Islands, many at risk from invasive species such as the elusive snake. An ever present risk is the arrival of the brown tree snake on airplanes from Guam where it has wiped out all the forest birds. Originally, plants and animals made their way to the once barren Hawaiian Islands borne on ocean waves and the jet stream. Early species adapted to the isolated islands 2,400 miles from the nearest continent, and 850 miles from the nearest group of atolls. Some became defenseless without pressures from predators. A species of Hawaiian raspberry, "akala," lost its thorns; some bird species lost their ability to fly. Many of these early species - colorful forest birds and vulnerable tropical plants - are now at risk from alien invaders. At first, it was the arrival of Polynesian and European settlers that upset this ecosystem, through the introduction of alien animals and clearing of the land for agriculture. Polynesian colonizers brought domestic animals including dogs, pigs, and chickens. Today, habitat degradation and predation by feral goats, feral cattle, feral pigs, rats, and deer, competition from alien plants, natural disaster, human impacts, and the lack of legal protection or difficulty in enforcing laws that are already in effect, are all cited by the U.S. Fish and Wildlife Service as threats to more than 300 endangered Hawaiian plant and animal species.
Hawaiian biologists say the first introduction was the small pig the Polynesians brought with them. It is not thought to have ranged to more than 3,000 feet and is not thought to have caused great damage. But when the larger domestic pig ran wild after its introduction by Europeans, the two hybridized, the resulting larger feral pig ranges higher and does much more damage. The wild pigs crush and rip up plants, destroying long established root systems and causing soil erosion. Pigs turn the forested land into wallows which become an ideal breeding for mosquitos. These in turn pose a threat to native birds, especially the Hawaiian honeycreepers, apapane, by transmitting various forms of malaria. The mongoose, introduced by Europeans to kill rats in the sugar cane fields, have caused harm to earlier species. The plan failed because the mongoose sleeps in the night and hunts in the day, while the rat sleeps in the day and hunts in the night. Instead of eating rats, the mongoose preyed upon Hawaii's state bird, the Nene goose, now an endangered species. Plant invaders from South America are now considered one of the most dangerous threats to Hawaii's ecosystems. A species of vine called miconia is known as "the brown tree snake of the plant world" because it winds around native plants, choking the life out of them, blocking out oxygen and sunshine. As the vines kill the native tree, the dead trees fall and let in too much light. Like a chain reaction, the second and third layers in the Hawaiian forest are harmed. People invade the ocean and the beaches that used to be breeding grounds for green sea turtles, humpback whales, and Hawaiian monk seals.
The Hawaiian Humpback Whale Sanctuary was established in Maui waters in 1997, but vessel traffic, enthusiastic whale watchers and ghost fishing gear can harm marine mammals, driving them away from spots they appear to prefer for breeding activities. Calves and young whales are especially vulnerable to heavy boat traffic, and federal regulations prohibit approaching a whale more closely than 100 yards. Conservation groups are leading the way to a better understanding of Hawaii's unique and endangered environment and the need to balance natural resource protection with the demands of a growing human population. A project called HEAR - Hawaiian Ecosystems at Risk - provides technology and information to resource managers, decision-makers, and the general public to support the fight against harmful alien species in Hawaii and the Pacific. HEAR is committed to stopping the influx of new pests, currently estimated as entering Hawaii at two million times more rapid than the natural rate. Visitors to Hawaii have an important role to play in conserving Hawaiian native species. When you visit the islands, learn to identify the most threatening pests and to report them. Fill out your Department of Agriculture declaration form completely and honestly, and don't bring plans, fruits, vegetables, or illegal animals with you to Hawaii. Clean your hiking boots, running shoes, and other gear before entering native forest areas and when traveling between islands. Don't spread crop pests by sharing diseased plants, and if you sail or fly to the islands, police your ship for alien invaders. Copyright Environment News Service (ENS) 2002. All rights reserved. |
Brown tree snake (Photo courtesy 
Hunter with feral pig in Hawaiian forest (Photo courtesy 
Humpback mother whale and calf in the Hawaiian Humpback Whale Sanctuary (Photo courtesy 