The Chittenango Creek, which runs north for
about 48 twisting kilometers in central
New York, has few distinguishing
markers: The stream is generally only a couple of feet deep, and the towns it
passes through are similarly small and overlooked.
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One exception is
found a couple kilometers from the source of the creek, where the riverbed
flattens out and drops 50m over a series of limestone cliffs that are segmented
into ledges and still smaller rock shelves. The fractal qualities are magnified
by the foaming water that tumbles in thin layers down the cliffs. On some
mornings, sunlight from the southeast illuminates the mist, and the whole area
glows.
Around this time
on a recent Thursday, a dozen people clustered on one side of the falls, along
two ledges that were blanketed in snakeroot, yellow jewelweed, spotted Joe-Pye
weed and pale swallowwort. Here, in an area about the size of a living room, is
the only known habitat of a small, critically endangered invertebrate with a
marbled spiral shell: the Chittenango ovate amber snail.
A thousand
species of land snail worldwide are known to be at risk of extinction. Most
have very specific needs and a limited geological range, so scientists have
been studying their populations to understand how changes in the environment
could affect biodiversity more broadly. “Land snails are apt to be the real
canaries in the coal mine for these sorts of changes,” said Rebecca Rundell, a
biologist at the SUNY College of Environmental Science and Forestry.
Rundell is conducting such research on endangered
land snails in the Republic of Palau, and similar projects are underway in such
far-flung places as Hawaii and Bermuda. But the same issues are at play in her
backyard, with the “Chits,” which can only flourish in nearly 100 percent
humidity and the shade of deciduous forests. “The conservation status of our
local snail is emblematic of what is happening to land snails globally,” she
said.
And so Rundell’s
team, with volunteers and employees from the New York Department of
Environmental Conservation, gathered on the side of the waterfall, their feet
and knees planted cautiously but firmly on rocks, and sifted gently through the
dirt and roots. Their goal: to figure out how many of these snails remain in
the wild without crushing any in the process.
Cody Gilbertson,
a biologist in Rundell’s lab who has helped lead research on Chits for the past
decade, was up near the top of the falls watching over five mature snails that
she had raised in captivity and was preparing to release. “Snailsitting,” she
called it.
When survey
efforts first started, wild Chits could be found all over the spray zone of the
waterfall. But those numbers dropped steadily over the years. A rockslide in
2009 took out a large chunk of the population, and heavy rainfall damaged the
habitat periodically. In 2010, the number of wild Chits was around 1,000; in
2015 it was around 400; this year, after five preliminary surveys earlier in
the summer, Gilbertson said, “the numbers are quite dismal” — in the double
digits.
The day before the survey, Gilbertson sat in a
white-walled lab in Syracuse, New York, counting out baby Chits, each smaller
than a sesame seed, that speckled the inside of plastic deli containers. Some
150 mature snails and 200 juveniles had been raised in the lab, and one of the
babies had seemingly disappeared.
“It’s very
tedious,” Gilbertson said, handing the container to Alyssa Whitbread, a researcher
who has been helping study Chits since 2017. Using a small, flat-tipped
paintbrush, Whitbread started to comb through the leaves that lined the
container. “Sometimes they like to hide in cracks that you don’t think to look
in,” she said.
A “leaf lasagna” prepared for the terrarium of captive Chittenango ovate amber snails at the SUNY College of Environmental Science and Forestry in Syracuse, New York, on August 26, 2022.
Chits are born
with their shells, which start out pearly white and darken over time. Hard
enough to see when alive, they often disintegrate after death. Counting the
captive animals — which Whitbread, Gilbertson, and Marlene Goldstein, an
undergraduate at SUNY, do each week — often takes hours. But the snail
population in this lab and the wild one at the Chittenango Falls are the only
two in the world. Lose track of one snail, and you’ve lost track of one of the
last Chits on Earth.
Still,
existential rumination can go on only so long. “At a certain point, we just
have to move on,” Gilbertson said, after Whitbread failed to find the itinerant
snail.
Most of
Gilbertson’s scientific career has been dedicated to figuring out how to keep a
Chit population alive in captivity. An effort in the late 1990s failed, and a
decade later, when Gilbertson first collected a handful of adults and brought
them into the lab, they refused to eat anything. The animals slowly died, as
Gilbertson “frantically grabbed stuff from the falls” to try to feed them, she
said.
Then one day,
miraculously, a cherry leaf worked.
Maintaining a
captive population of Chits can theoretically bolster the existing population
of wild snails, serve as a last-ditch defense against their extinction and,
perhaps eventually, be the source for a new wild population in a different
waterfall spray zone. But Gilbertson and Rundell were painfully aware that the
decade-long efforts to reintroduce snails to Chittenango Falls have not offset
the wild population’s decline. “Even captive breeding is unlikely to save the
day for these snails,” Rundell said.
On that sunny
Thursday, the surveyors tried to find as many wild snails as possible in 15
minutes, placing them in Tupperware containers and, later, under a park
pavilion, sorting through the animals and inspecting them closely. The snails
would be released back into the environment once tiny numbered tags had been
super glued to their shells.
A dark spot on
the foot of a Chit distinguishes it from what the researchers refer to as
Species B — Succinea putris, an invasive land snail that is native to
Appalachia and now also lives in the Chits’ habitat and may compete for
resources. Little is known about Species B’s interactions.
“I get emails
all the time, like, ‘I found a Chit; it’s in my backyard,’ ” Gilbertson said.
“And I look, and it’s Species B.”
After an hour of
sorting, the team collected five Chits. Two had been caught earlier in the
summer; one had been released from the captive population a year ago and had a
white tag on its shell; two were new finds. “I’m really happy to see some fresh
snails,” Gilbertson said. “It gives me hope.”
She added: “By
going into this tiny world, we’re able to see something that we don’t normally
see. And I think that in general, people don’t realize that the little guys are
just as important for conserving.”
Before departing, a few of the researchers walked
back down to the falls to release the snails that had been collected as well as
the five snails that Gilbertson had picked out of the captive population for
reintroduction. The sun shone directly overhead, and water spilled down the
falls like white paint. Every bit of ground was drenched in sunlight and
steaming in the heat, except for the living room that harbored the only wild
population of Chittenango ovate amber snails in the world. This corner of the
Earth was cool, shady and damp — just right.
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