Some plants brought to Hawaii by humans have exploded in an environment lacking the natural
controls that kept them in check in their homeland. For example, banana poka, an attractive
passion flower vine, is limited in its native South America by insects that feed on it. But in Hawaii,
banana poka has already smothered over 70,000 acres of native forest on two
islands and threatens to destroy even larger areas unless effective controls are found. Species
that pose even greater threats are poised to invade Hawaii. For example, on Guam the
brown tree snake has wiped out 9 of the 11 species of native forest birds since 1975. This
snake stowed away on flights from Guam to Hawaii. It has been found here by inspectors on six
occasions. But how many times has it not been intercepted? If it establishes itself here, the
outlook for protecting Hawaii's native birds will worsen dramatically.
The brown tree snake is a frightening symbol of a disturbing trend: each year Hawaii is invaded by at least 12 new non-native species. As many as 35 new, non-native species have been known to invade Hawaii in a single year. Among these are species destructive to forests, agriculture, and human health. Without strong, effective inspection and enforcement programs, there will be more destructive and costly invasions.
HUMAN DISTURBANCES: The voyaging canoes of the Polynesians brought the first humans to Hawaii just 1,500 years ago. With humans came the need to clear land for food and housing, and the introduction of new plant and animal species. Unfortunately, some of these new species -- such as pigs, dogs, and rats -- preyed on the native birds, plants, and insects; and others competed with native species for habitat. For cultural purposes the feathers of thousands of forest birds were used to create ceremonial capes.
Damaging introductions accelerated greatly with the arrival of Europeans in the late 1700,s. They introduced many more non-native species, including cattle, goats, European boars, and mosquitoes. They felled much of the forests for agriculture, grazing, and fuel for sugar mills. Just as European and Asian diseases decimated the native Hawaiian people, so did increased forest clearing and introduced pest species continue to take a heavy toll on native Hawaiian plants and wildlife.
Today, land conversion to agriculture, ranching, and residential uses has permanently displaced native vegetation on over half of the Hawaiian landscape. Coastal and lowland areas have been particularly affected. Wildfires often destroy rare dry land native plants. Flammable non-native weeds take over these burned areas, creating a vicious cycle of destruction. Modern fishing techniques threaten marine and seabird life. Increased development, tourism, and a growing population continue to impact Hawaii's natural resource base.
While Hawaii's early inhabitants relied heavily on Hawaii's natural resources for their survival, our survival today depends on saving what it left of our native ecosystems. We need to strike the proper balance between the needs of an island economy and growing population, and the preservation of Hawaii's limited natural resources.
RETURN TO OUR ENVIRONMENT -- ONLINE CONTENTS PAGE