An Existential Battle Over an Infinitesimal Snail

March 1, 2018/ Jason Bittel / Conservation, Natural Resources Defense Fund, North America, Oceans, Resources, Species

Published by the Natural Resources Defense Fund

The beaverpond marstonia is a rare snail with a tan shell, a taste for submerged clumps of vegetation, and a known habitat of just three creeks in Georgia. It stands about as high as a stack of two nickels and is thought to eat tiny bits of organic matter and aquatic microorganisms. And, it might be gone forever.

In December 2017, the U.S. Fish and Wildlife Service released a statement saying the beaverpond marstonia is now thought to have disappeared from the face of the earth. This makes the tiny snail the first animal to be listed as extinct under the Trump administration.

You might never have heard of beaverpond marstonia. But you might reasonably think that an animal now deemed to be extinct would have previously appeared on a list of animals considered threatened or endangered. Did the snail somehow slip under the radar?

Well, no. And this is where things get awkward.

The beaverpond marstonia was discovered in 1977 by a renowned snail expert named Fred Thompson. Within just a few years, scientists recognized that the snail was in danger, thanks to its small distribution and reliance on drought-susceptible streams. In 1984, the snail was added to a candidate waiting list for Endangered Species Act protection—a sort of limbo where lost species wait for their number to be called based on priority.

Unfortunately for the beaverpond marstonia, its day never came. Starting around the turn of the millennium, Georgia entered a period of drought that would last nearly two decades. To make matters worse, the streams where the snails lived were tapped for irrigation water. If the snails were still there, experts worried at the time, draining the water from their already depleted habitat could be the species’ death knell.

Still, 10 more years would pass without any official recognition from the Fish and Wildlife Service that the snail was in trouble. Fed up, in 2010 the Center for Biological Diversity petitioned the FWS to list or get off the pot, so to speak. Six more years came and went without action. “Then we sued over it because the service basically ignored the petition,” says Tierra Curry, a senior scientist with the Center for Biological Diversity.

Finally, the snails would get their due. Nobody had seen one alive since the year 2000, but now the federal government had a court-ordered mandate to go out and find them—if they still existed. Jason Wisniewski, a senior wildlife biologist for the Georgia Department of Natural Resources, was the expert who got the call.

Wisniewski is one of only a few people in the country qualified to identify beaverpond marstonia. Not only are the critters incredibly small, but identifying them requires a high degree of skill and familiarity with the other mollusks found in an area. That, and a microscope. “You have to look at the shape of the penis and the glandular structure in order to positively identify it,” says Wisniewski.

Wisniewski and his colleagues did find some snails they thought might be beaverpond marstonia, but their hopes were dashed when DNA tests came back positive for other species. In the end, the scientists came up empty, and the FWS pronounced the snails kaput.

Interestingly, Wisniewski says he won’t be the least bit surprised if the snails turn up eventually. To do a really good job of looking for the mollusks, he and his team would need several seasons—and they were given only 90 days. He says the snails grow to their largest and most easily detectable size between about October and April, which just so happens to be Georgia’s wettest part of the year, and when Wisniewski and his colleagues conducted their search.

This means more of their habitat is underwater and streams are difficult to access. It’s also cold. “In some of these places you have to swim in order to get across the creek or over to the next habitat,” says Wisniewski. “Within a few minutes your hands are too cold to work efficiently.”

Even if the snail’s fate is uncertain, an extinct designation means the streams it once lived in won’t be receiving federal protections anytime soon. And that means other species who depend on them could also be in trouble. “The beaverpond marstonia tells the story of that place, because it was there for thousands and thousands of years and now it’s not,” says Curry. “It means that something bad has happened there. It means that we have to do a better job at taking care of our freshwater resources.”

The American Southeast has been particularly hard hit by extinction, says Curry, perhaps because the region has so much biodiversity to begin with. Today we’re talking about the beaverpond marstonia, but you could write similar stories for the two butterflies from Florida declared extinct in the past decade—the Zestos skipper and rockland grass skipper; or the Tatum Cave beetles of Kentucky; the green, yellow, and turgid blossom pearlymussel; the South Florida rainbow snake; the Florida fairy shrimp; and four dozen other species from this region that have blinked out within the past 100 years.

Wisniewski says he will continue to look for the beaverpond marstonia despite the listing. And if just one holy snail is found, would that be enough to earn the species a spot on the Endangered Species List? Maybe. Maybe not.

“We would have to petition for it again,” says Curry. “We would start all over.”

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