Once found throughout the Columbia River basin, the ashy pebblesnail and the shortface lanx have disappeared from much of Washington. The Center for Biological Diversity hopes to change that. The nonprofit group has petitioned the U.S. Fish and Wildlife Service to add both species to the federal endangered species list.
While the snails may not be as popular or appealing as Washington’s other endangered species, such as the gray wolf, humpback whale or pygmy rabbit, they are “an important part of the web of life,” said Noah Greenwald, endangered species director for the center.
“They provide food for bigger organisms, like salmon and steelhead and other fish. All things are connected. If you remove them, then there’s going to be less fish for people,” Greenwald said in an interview Tuesday.
The snails also attach themselves to rocks and stream bottoms and eat algae and detritus from the rocks, which helps keep the streams and rivers clean.
“These little snails speak volumes about how poorly we’ve treated our Pacific Northwest rivers, which desperately need stronger protections,” Greenwald said.
Ashy pebblesnails are small, tan or reddish snails with pale circles around their tentacled eyes. The shortface lanx is sometimes called the giant Columbia River limpet (even though it’s not actually a limpet) for its characteristic volcano-shaped cone.
Historically, both snail species were found throughout the Columbia River basin in Washington — including in Clark County — Oregon, Idaho, Montana and British Columbia.
Today, the ashy pebblesnail’s habitat has been reduced to the lower and middle Snake River basin in Idaho, the Grande Ronde River in Washington and Oregon, the Okanogan and Methow rivers in Washington, and the Hanford Reach of the Columbia River, also in Washington. It’s possible some specimens may still be found in the lower Columbia region, according to the Washington Department of Fish and Wildlife.
The shortface lanx is now found only in the Okanogan River and Hanford Reach with small populations found in the Methow and Grande Ronde rivers. Limited numbers can also be found in parts of Oregon and Idaho.
Both species require cold, well-oxygenated streams and rivers. They cannot survive in waters with mud or silt, extreme variations in water levels, an abundance of aquatic plants or algae or where dredging or mining occurs.
“They are great indicators of stream health,” Greenwald said. “If we lose them, we’ve altered rivers in ways that are harmful to us, as well.”
Both species are threatened by dams, agriculture, urbanization, logging and other threats, according to the center. And as temperatures in rivers and streams increase due to climate change, Greenwald warned that available habitat for the snails will continue to decrease.
Under the Endangered Species Act, the Fish and Wildlife Service has one year to respond to the center’s petition. However, the center said the agency rarely meets this deadline and often requires a legal challenge before action is taken.
