Northwestern Hawaiian Islands - Biodiversity and Endemism

Biodiversity and Endemism

The Hawaiian Islands are about 2,500 miles (4,000 km) from North America and 3,800 miles (6,100 km) from Asia, and it is because of this isolation that the Hawaiian Islands have extraordinary numbers of unique species. Only a species that could fly or swim immense distances could reach the archipelago. But whereas Polynesians, and later, Europeans, have largely altered the ecosystem of the Main Hawaiian islands by introducing alien species, the ecosystems of the NWHI remain, for the most part, intact. The extensive coral reefs found in Papahānaumokuākea - truly the rainforests of the sea - are home to over 7,000 marine species. Of the many species that live here, over 1,700 species of organisms are endemic to the Hawaiian Islands (i.e., they are found nowhere else). For this reason, the region has been dubbed "America's Galapagos."

Though not subject to nearly as much extinction as the main islands, the Leeward Islands have had their share of abuse. From the late 19th to the early 20th centuries, fishermen, guano miners, and feather hunters killed most of the birds and sea life living in the NWHI. Rabbits were introduced to Laysan and Lisianksi, where they multiplied and devoured most of the vegetation, permanently extinguishing several species. Fortunately, almost all of the damage was reversed, and the islands were restored largely to their pre-exploitation state.

Some of the endemic species of the NWHI include the Nihoa and Laysan Finch, the Laysan Duck (the "rarest native waterfowl in the United States"), and the Nihoa fan palm. Other notable species are the Laysan Albatross, the highly endangered Hawaiian Monk Seal, and the Green Sea Turtle. The only native trapdoor spiders in the Hawaiian archipelago (Nihoa spp.), recently discovered, are found only here. Most endemic species are highly vulnerable to extinction as one major catastrophic event could wipe out all of the vegetation on each small island. Additionally, seventy percent of all coral reefs in the United States are found here.