Potomac Gorge Groundwater Invertebrates

Some of the most distinctive animals of the Potomac Gorge are ones we rarely, if ever, see. They are tiny creatures that live underground and in the moist soil below leaf litter. Several species of these invertebrate, or spineless, animals are so rare they are found only in and near the Potomac Gorge.

The Potomac groundwater amphipod is a crustacean found almost exclusively here and in similar locations south to Richmond, VA. In all the world, there are believed to be only 3,000 to 10,000 of them. A second amphipod, called Pizzini's cave amphipod, is found in a larger range but in smaller numbers. Both types of creatures are also known by the common name "scuds."

The Appalachian springsnail, or Fontigens bottimeri, is a mollusk found only in Maryland, Virginia and Washington, D.C. Gastropods are mollusks.

The Potomac Gorge is a hotspot for these little animals. Above ground, tiny crustaceans and mollusks can be found in the moist seeps, streams and in leaf litter. Scientists believe that the underground homes of these scuds and snails are the crevices and cavities in bedrock. It’s even possible that their underground communities connect from one side of the river to the other.

You would think underground fauna found inside park boundaries would be immune to threats. Unfortunately, there is interaction between the Gorge’s small streams and its underground environment. This means that whatever gets into tributary streams before they enter the Gorge can affect these underground environments. So chemicals and fertilizers that run-off into small streams can do damage even below the surface. And lawn-care products used inside the parks can have a similar effect on streams and seeps. Oil and other petroleum products drip from visitors’ cars, then run-off into seeps.

None of these threats are considered severe—yet. So efforts are being made to protect these unique habitats now before serious problems arise in the future.

Last updated: April 10, 2015

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