The tiny snail that just helped save its species from possible extinction wasn’t supposed to be there in the first place.
Researchers at the SUNY College of Environmental Science and Forestry didn’t need that baby snail in their lab. They already had ten critically endangered Chittenango ovate amber snails (Novisuccinea chittenangoensis) living in their facility. That’s all they were allowed to collect under a special permit from the U.S. Fish and Wildlife Service (FWS). At the time only about 340 COAS snails (as they’re abbreviated) remained in the wild at their only habitat, about 140 square meters beside the crashing Chittenango Falls waterfall in Cazenovia, New York. Bringing any more into the lab could have further threatened the species. Half of them had already died after a massive rockslide in 2006.
The SUNY researchers have spent the past few years trying to figure out how to breed COAS in captivity to boost the wild population, a long and involved process that required a lot of trial and error. The first step was to replicate their wild habitat in a laboratory setting. “This was tricky,” says Rebecca J. Rundell, whose lab ran the project. They had to simulate the same temperature, humidity and light exposure that the snails would experience in the spray underneath the 167-foot waterfall.
Once they accomplished that, the researchers needed to provide food for any snails they brought into captivity. There was just one problem there: Nobody knew what COAS ate.
Graduate student Cody Gilbertson tried several potential diets on a related snail species until her team found a diet that appeared like it would work with COAS. With that information and food in hand, they finally brought a few endangered snails in from the wild.
The snails ate initially but didn’t thrive on any of the foods the team provided. “They shut down and stopped eating,” Gilbertson says. “I ended up releasing them before anything happened to them.”
The team tried again with another batch of snails. Gilbertson continued to bring different kinds of vegetation from around the waterfall to see what they would eat. One day the leaves she brought in contained something extra and unexpected.
“A little stowaway snail that was about 4mm in size came in on the vegetation,” she says. “That’s how all of this came together.”
Gilbertson got permission from FWS to keep the additional hatchling snail in the lab and started watching it every day. She offered it different food items to see what might work. “Eventually I came to dead cherry leaves,” she said.
That did the trick. “Very specifically it liked the shade leaves.” Unlike leaves that grew in the sun—which had a waxy, tough outer layer that slowed decay—the shade-grown leaves were easier for the snail to consume. The tiny snail munched away until nothing but the veins of the leaves were left.
“I kept feeding it cherry and it started taking off in growth,” Gilbertson says. “Its shell looked beautiful, it was growing normally, and it looked shiny and vibrant. From that I could really provide a better diet for the other adults.” The tiny snail blossomed and eventually reached 21mm in size.
This spring Gilbertson brought in two more snails. “They immediately mated and consumed the diet I was providing to the one hatchling,” she reports.
Soon the snails became baby-making machines. By June the lab had hatched more than 600 baby snails, nearly tripling the entire population for the species. Last month they released 200 of them back into Chittenango Falls. They’ll now monitor the released COAS—a few of them were large enough to mark with the same kinds of tags that other researchers use to track honeybees—while keeping up with laboratory breeding. “We’ll continue to breed them in the lab and release the adults, then raise the babies, then bring in more adults next year,” Gilbertson says. “We’re keeping the genetic diversity somewhat managed that way.”
Of course, this doesn’t put COAS completely in the clear. Rundell notes that the miniscule habitat itself still faces several current and potential threats. Invasive pale swallow-wort plants have arrived and choke off native vegetation. Visitors to the park climb over barriers to see the waterfall and could trample the snails underfoot. Climate change could dry up the waterfall itself. “If there is nowhere left to reintroduce baby snails to, then we have ultimately lost,” she says.
Luckily the news of the COAS release has already generated a lot of local media attention and excitement from the community. “It has been perspective-shifting to see how everyday people can get interested in a tiny little snail,” Rundell says. “Word has been spreading about this species and people in the area are increasingly curious about it and proud of it. The more people that care about their own species locally, even the tiniest ones, the better off our wild places will be across this country and around the world.”
Gilbertson says their success so far has been exciting and that they hope to apply it to other species that have extremely limited populations. She also hopes the news inspires others. “There’s not a lot of positive news out there,” she says. “It’s nice to have glimmers of hope for other conservation efforts. It can be done.”
Photo: Cody Gilbertson
Previously in Extinction Countdown:
- Microjewels: Stunningly Beautiful Snails Going Extinct As Soon As They Are Discovered
- Snails and Endangered Gorillas: Perfect Together?
- The Incredible Mr./Mrs. Limpet: The Endangered, Sex-Changing Sea Snail
- Ireland's Failed Snails: 2 Species Already Extinct, Dozens of Other Mollusks Endangered
- Should We Stop Selling Nautilus Shells?