Researchers hope Hawaii’s ancient climate could hold clues for its warming future

A graduate student at Hawaii Pacific University is conducting a snail study to investigate what caused their extinction at Oahu's Kaena Point.
Published: Feb. 22, 2022 at 5:20 PM HST|Updated: Feb. 22, 2022 at 5:52 PM HST
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HONOLULU (HawaiiNewsNow) - At Hawaii Pacific University’s Department of Natural Sciences, graduate student Samantha Arsenault uses a microscope to scrutinize shells from different species of extinct Hawaiian snails she collected at Kaena Point.

Preliminary analysis indicates the snails existed long ago before becoming extinct.

“They are eroding by the thousands out of this cliff face,” she said. “You can find them along the ground. You can pick them up along the cliff just by hand. No specialized tools are needed.”

Arsenault is trying to create a timeline of events that changed the climate at Kaena Point.

Her research suggests the shells date back 30,000 to 46,000 years, when the coastal area at the western edge of Oahu was covered in forest.

“These snails were thriving out there at this time. So this was a wet complex forest right down to the inter-tidal zone,” said Brenden Holland, HPU associate professor of Natural Sciences.

He said the snails died off when the area dried up.

“They just don’t move actively much at all. We think they just stayed in place and went extinct one by one as the plants all died out,” he said.

Arsenault is measuring the shells and looking for differences and similarities in preparation for deeper isotopic analysis.

“All of these can give us different information about what the environmental conditions were like at the time these snails were alive,” she said.

Biologists differ in their estimates of the total number of species of endemic Hawaiian snails, but it could be as high as 800.

“One reason we don’t know for sure is because we’re losing so many so rapidly,” Holland said.

Understanding how snail species disappeared may help save other Hawaiian snails from extinction.

“Doing this kind of study that gives us information about the climate in the past, it would be invaluable information,” Arsenault said.

“It’s really unusual for biologists in Hawaii to have an opportunity like this to look at a natural extinction event,” Holland said. “Most of the extinction ... is being driven by human activity.”

Arsenault hopes to wrap up her research by December.

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