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Hawaii tropical moist forests (OC0106)

Hawaii tropical moist forests
Oahu, Hawaii, USA
Photograph by David Olson


Hawaiian Islands
Tropical and Subtropical Moist Broadleaf Forests

2,600 square miles (6,700 square kilometers) -- about the size of Delaware and Rhode Island combined

· Islands of Life
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern

Islands of Life

One of the world's biological treasures, the Hawaiian Tropical Moist Forests ecoregion is home to a high diversity of endemic species. For 70 million years, the Hawaiian Islands have been isolated from the rest of the world by vast stretches of the Pacific Ocean, and this isolation has resulted in the evolution of an incredible diversity of fungi, mosses, snails, birds, and other wildlife. In the lush, moist forests high in the mountains, Koa and `Ohia'lehua trees are draped with vines, orchids, ferns, and mosses. This diversity of habitats and richness of life make Hawaii's moist forests some of the most spectacular places on Earth.

Special Features Special Features

From lush rain forests to bogs, a surprisingly diverse mixture of habitats makes up the Hawaii Tropical Moist Forests ecoregion. This diversity includes the world's wettest rain forest on Mount Waialeale, which averages 450 inches (1,143 cm) of rainfall per year. While we often associate Hawaii with beautiful rain forests, which occur on the mountaintops of the smaller islands and on the windward sides of the larger islands, the islands' moist forest regions are also home to wet shrublands and bogs in swampy areas.

Did You Know?
Hawaii is the only state in the U.S. with a true tropical rain forest.

Wild Side

An amazing array of endemic plants and animals live in the tropical forests of Hawaii. Hawaiian hawks soar over forests of Koa and `Ohia'lehua trees, which provide habitat for unusual vines and spectacular native tree snails. Forest birds such as the Hawaiian crow and Hawaiian thrush call the moist forest home. Native honeycreepers also live here. They are a group of birds that have diverse bill structures for feeding on different plants in mesic and wet forests. Several unusual carnivorous caterpillars are endemic to Hawaii. Some of these caterpillars mimic twigs and snatch prey that mistakenly comes too close; others perch on tree trunks, or wait on ferns and leaves. When triggered by touch, these caterpillars snatch their prey.

Cause for Concern

Almost all the native plants in the Hawaiian islands occur nowhere else on Earth, and most are defenseless against introduced species such as pigs. Pigs were brought to these islands by humans from Polynesia and Europe and have since escaped and turned wild or "feral." As they have reproduced and spread, the pigs have destroyed native vegetation, caused soil erosion, eaten bird eggs and nestlings, spread weeds and diseases, and polluted water supplies. Other introduced plants and animals are crowding out and destroying Hawaii's native plants and animals, while recreational activities threaten large blocks of montane forest. Hawaii has already lost two-thirds of its original forests to agriculture, clearing, and fire, and half its native birds through habitat loss and introduced disease. Saving the remaining native species and habitats is now a race against time.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.

All text by World Wildlife Fund © 2001