Hawaii Moist Forests

/ ©: WWF-Canon / Paul TRUMMER
Water lilies (Nymphaea), Hawaii, USA.
© WWF-Canon / Paul TRUMMER

About the Area

For 70 million years, the Hawaiian Islands have been isolated from the rest of the world by vast stretches of the Pacific Ocean. This isolation has resulted in the evolution of an incredible diversity of fungi, mosses, snails, birds, and other wildlife. These moist forests have an extraordinary percentage of endemic species, including 95% of plant species, and 99% of invertebrates.

Several groups have radiated into many species - for example over one-third of the world's fruit fly species are found here.

Hawaii includes the world's wettest rain forest on Mount Waialeale, which averages 1,143 cm of rainfall per year.

Size:
6,700 sq. km (2,600 sq. miles)

Habitat type:
Tropical and Subtropical Moist Broadleaf Forests

Geographic Location:
North Pacific Ocean-Hawaii Islands

Conservation Status:
Critical/Endangered

Local Species
Unique species include Hawaiian land snails, Hawaiian lobelias, Eupithecia moths (predatory caterpillars), Hawaiian silversword alliance (Madiinae), Hawaiian honeycreepers (Drepanidae) - believed to have evolved from a single ancestor, in the same way that Darwin's finches evolved in the Galapagos Islands, these birds have remarkably shaped bills, adapted to different feeding habits.

These forests are also noted for the diverse assemblage of shrubs and trees that were found within the Koa and ‘Ohi’a forests. Bogs occur on montane plateaus or depressions and consist of a variety of sedges, grasses, ferns, mosses, small trees and shrubs that form irregular hummocks. The once abundant land snails (with 99% endemism) are now over 50% extinct with many of the remainder endangered.
/ ©: WWF-Canon / Paul BARRUEL
Hawaiian goose (Branta sandvicensis) drawing.
© WWF-Canon / Paul BARRUEL

Featured Species

The Happy face spider (Theridion grallator) is normally shy and retiring. It lives on the undersides of leaves in rainforests. The happy-face spider is endemic to the Hawaiian archipelago but is only found on 4 of the islands: Oahu, Molokai, Maui, and Hawaii. It hunts primarily at night and feeds on small insects that it encounters.

Its name is derived from the colorful markings on its abdomen that look very similar to a smiling human face. The pattern is variable and may even be different colors. The happy face spider is one of the few spiders known to take care of its young.

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Threats
Lowland and foothill moist forests have been largely eliminated. 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.

Deforestation, grazing, introduced species, development, and recreational activities are all real problems. Several important areas of relatively intact tropical moist forests currently have no or incomplete protection.
WWF’s work
WWF works to help protect ocean habitat and support commercial fisheries. This includes work to establish a network of ecologically representative and well-managed marine protected areas, in both national and international waters. WWF and IUCN have identified the high seas as a gap in this global protected areas network, and have developed an action plan to facilitate the establishment of high seas marine protected areas.

WWF is one of several partners in OASIS (Oceanic Seamounts – An Integrated Study), a scientific project funded by the European Commission that integrates physical, biogeochemical, and biological research. One of the aims of the project is to develop concepts for seamount conservation, including management plans.

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