Not seen or collected for science since 1933, the oblong rocksnail of Alabama’s Cahaba River was declared extinct in 2000. In 2011, biology grad student Nathan Whelan took a second look at a tiny rock he had picked up from the river…
This is The Unlikely Tale of a Tenacious Snail, a Science Friday report about this tiny lazarus species, and some of the conservation and restoration efforts being led by the Alabama Aquatic Biodiversity Center to preserve the biodiversity found in the rivers of the American south.
Alabama’s ten river basins have a variety of unique animals, including 13 snail species not found anywhere else on the planet. From wikipedia:
The waters of the Cahaba are home to more than 131 species of freshwater fishes (18 of which have been found in no other river system), 40 species of mussels, and 35 species of snails. The river has more fish species than can be found in all bodies of water in California. Sixty-nine of these animal species are endangered…
Due to damming for hydropower, pollution, transportation, and erosion, it has suffered losses of species. Almost a quarter of the original documented mussel species in the Cahaba have disappeared with similar trends in the fish and snail numbers… These species feed other aquatic dwelling animals, improve water quality by eating algae, and even indicate environmental issues due to their receptiveness of pollution.
And a bit more on why are mollusks important:
Mollusks act as Mother Nature’s vacuum cleaner by filtering water through their bodies. In the most basic terms, they are filter feeders who suck in water and pull out bacteria and suspended solids. A small mussel can filter over 12 gallons of water per day. In healthy ecosystems throughout the Southeast, freshwater mollusks historically numbered in the hundreds of millions.