| BIRMINGHAM, Ala, July 26
BIRMINGHAM, Ala, July 26 A snail in Alabama has
become the first in U.S. history to recover from the brink of
extinction and is now merely threatened rather than an
In 1991, the Tulotoma snail was barely clinging to one
small place, extinct in 99 percent of its historic range. The
snail now has expanded to 10 percent of its range.
"The Clean Water Act and improved land use conditions have
allowed the snail population to start growing again," said Jeff
Powell, senior biologist with the U.S. Fish and Wildlife
Under the Clean Water Act, the federal government has
implemented pollution control programs and set water quality
standards for contaminants in surface waters.
At the bottom of the food chain, snails consume algae and
provide food for other species. More snails indicate better
The orangish, two-inch long Tulotoma snail with elegant
swirls was once prized by Native Americans for its beauty and
crafted into jewelry. Its historic range was destroyed in the
early 1900s, when dams emerged on Alabama's flowing rivers.
Snails and mussels thrive on flowing water, which has
higher oxygen content. Powell described impounded lakes created
by the dams as "bathtubs" where oxygen goes down and
temperatures go up.
The Tulotoma snail's recovery resulted in part from an
agreement with the Alabama Power Company to release a steady
flow of water from its dam on the Coosa River.
"We changed to pulsing flows and installed aeration systems
to raise the oxygen. It has had a dramatic impact on the river
species," said Brandon Glover, a power company spokesman.
U.S. Fish and Wildlife biologists and others also embarked
on a diligent search for the Tulotoma and other species. New
populations have been found in three more tributaries, bringing
the numbers from 10,000 to hundreds of thousands.
Dispersed populations ease the vulnerability of a single
event wiping out the species, as was the case when pollution of
a small creek wiped out one of four populations of the snail.
Alabama is among the leaders in extinctions, with 29
snails, 28 mussels and two species of fish already extinct,
according to Michael Buntin, biologist with the Alabama Aquatic
The state also holds the record for a single mass
extinction, when a dam opened and wiped out 40 species.
One reason for the high numbers is Alabama's freshwater
biodiversity, which includes 310 species of fish, 150 snails
and 181 mussels, Powell said.
The diversity dates back to the Ice Age, when glaciers
stopped in Kentucky. Species took refuge in the southern
states, especially in Alabama, where the land slopes from
mountain to sea, Powell said.
(Editing by Colleen Jenkins and Greg McCune)