Predicting the Risk of Species Extinctions Due to Sea-Level Rise in the Northwestern Hawaiian Islands

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If current climate change trends continue, rising sea levels could inundate low-lying islands across the globe. The Northwestern Hawaiian Islands (NWHI) is a group of islands of great conservation importance that is threatened by sea-level rise. Stretching 2,000 km beyond the main Hawaiian Islands, the NWHI are a World Heritage Site and part of the Papahānaumokuākea Marine National Monument. Th...

If current climate change trends continue, rising sea levels could inundate low-lying islands across the globe. The Northwestern Hawaiian Islands (NWHI) is a group of islands of great conservation importance that is threatened by sea-level rise. Stretching 2,000 km beyond the main Hawaiian Islands, the NWHI are a World Heritage Site and part of the Papahānaumokuākea Marine National Monument. The islands support the largest tropical seabird rookery in the world, providing breeding habitat for 21 species of seabirds, 4 land bird species, and essential habitat for other resident and migratory wildlife. Because these are low-lying islands, even small increases in sea-level could result in the loss of critical habitat, increasing the risk of extinctions of species that are found nowhere else in the world.

 

The goal of this project was to provide managers with critical information on the vulnerability of the islands and the species that inhabit them to sea-level rise. Researchers used high-resolution topographic and vegetation models to predict the impacts of a range of sea-level rise scenarios on 20 islands. Results showed that a sea-level rise of +1 m would result in the loss of 4% of the total land area in the NWHI, while a rise of +2 m would result in the loss of 26% of the total land area and could leave 7 islands completely submerged. Researchers then explored the potential implications of sea-level rise for wildlife breeding habitats on each island. A loss of 4% of land area could leave more than 200,000 seabirds without nesting habitat. Species with limited distributions are especially vulnerable, such as the Laysan Finch, Black-footed Albatross, Laysan Albatross, and Hawaiian monk seal.

 

Understanding the vulnerability of these islands and their wildlife to sea-level rise will help managers determine the best course of action for helping these species persist in the face of climate change.