Sheila Conant says invasive species endanger unique Hawaiian animals, plants

Sheila Conant: Hawaii is unique in its rate of what we call endemism. And that is existence of species that occur in Hawaii and they occur nowhere else in the world.

Sheila Conant is a zoologist and conservationist at the University of Hawaii. She said Hawaii is the most isolated landmass in the world – and the protected conditions have allowed thousands of unique species to evolve and flourish. But she said many of these species have now become extinct or endangered.

Sheila Conant: We’ve had twenty more extinctions than New Zealand, and greater than fifty more than North America.

She said a major cause for the extinctions are plants and animals not native to Hawaii. These invasive species – brought to the island by people – have no natural predators. And, she said, the loss of one species can have a ripple effect on other species in the ecosystem.

Sheila Conant: We used to have birds that pollinated specific species of plants, and some of those plants have become very rare because their pollinators have become extinct.

Conant said invasive species are a worldwide problem. She’s working to preserve Hawaii’s native species by creating areas that are cleared of these species’ non-native predators. Our thanks today to NOAA Pacific Services.

Sheila Conant: The problem of invasive species is particularly important on islands, because the organisms that have adapted to the island don’t have good disease resistance, and they don’t have behavioral strategies to allow them to avoid predators.

Conant specializes in native Hawaiian birds. One of her favorite birds in the Laysan finch, found only on the remote island of Laysan, in the Northwestern Hawaiian islands. It’s currently uninhabited, but in the early 1900s, the island hosted a guano mining operation.

Sheila Conant: The person in charge of the guano mining thought introducing rabbits would be a great idea. Well, the rabbits ate all the plants, and as a result, three species of birds became extinct. Three species of birds found only on Laysan.

The Laysan finch survived, she said, but now there is only one recovered population in the world.

Sheila Conant: For the endangered birds in the main Hawaiian island, we don’t have a lot of alternatives for establishing populations where the birds will be free of threats. So what we try to do is remove the threats. One threat to the habitat is invasive ungulates – grazing animals like sheep, goats, all of which become feral. They eat the plants that the birds depend on. Only way to deal is set up areas and then clear them of those invasive ungulates.

Conant said this method has been in some cases successful, but it is very expensive. She said the best strategy is preventing accidental introduction of new invasive species.

Our thanks today to NOAA Pacific Services Center – linking culture, science, and people to build resilient Pacific Island communities.

April 19, 2010

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