Stowaway Snail Helps Save Species from Extinction
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.”
