HANCOCK -- Walking along Sideling Hill Creek, Laurie MacIvor spots a tiny black slit on the brown silty bottom of the sparkling mountain stream.
Most people wouldn't have seen it at all. But to MacIvor, a biologist with Maryland's Natural Heritage program, the dime-sized slit looked like the open mouth of a freshwater mussel buried in the mud.
It turned out to be more than just another mussel. It was Lasmigona subviridis, also known as a "green floater." The inch-long bivalve is listed as endangered in Maryland, and it is rare enough nationwide to be nominated for federal protection.
The mussel's discovery yesterday on the edge of a pool where Baltimore-area Boy Scouts swim every summer was further proof that the Lillian Aaron Straus Boy Scout Camp on the border of Washington and Allegany counties is some of the most ecologically significant land in Maryland.
Today, thanks to a deal engineered by the Nature Conservancy, a conservation group, the state is to buy the 1,194-acre Scout camp to protect a major portion of the creek and its rare plants and animals. The state Board of Public Works in Annapolis was expected to approve paying about $800,000 for the property.
Maryland Secretary of Natural Resources Torrey C. Brown called the camp a "fabulous spot," and he said the purchase will tie in with other state efforts to preserve Sideling Hill Creek.
The creek, which meanders 25 miles southward from Pennsylvania to the Potomac River, is rich in rare plants and animals, including the healthiest stand in the world of the federally endangered wildflower, Harperella.
A member of the carrot family, the delicate white flower blooms in midsummer in only a few streams in Maryland, West Virginia, the Carolinas, Georgia and Alabama.
The stream also features the state's largest stand of another wildflower, the crested iris, said Rodney Bartgis, another Heritage biologist. Rare butterflies and moths are found here, as are shale barrens, unusual rock outcrops with vegetation more likely to be found on Midwest prairies.
The purchase of the Scout camp culminates two years of effort by the conservancy, which has bought or preserved more than (( 29,000 acres in Maryland, often in cooperation with the state.
Sideling Hill Creek is one of the most pristine streams in central Appalachia because "it's still pretty undisturbed" by development and pollution, said Wilke Nelson, assistant director the conservancy's Maryland chapter. Only a few small farms and hunting cabins border its banks, and portions of the stream
flow through a state wildlife management area.
But its rare plants and animals still are vulnerable to a variety of man-made threats, including acid rain and runoff, according to state biologists.
State highway construction widening U.S. 48 dumped mud into the creek a few miles upstream of the Scout camp a few years ago. The silt threatened to smother some of the stream's Harperella, which grows in rocky crevices and gravelly shoals along the stream's edge.
The mud from the highway work eventually washed downstream, said Bartgis. And the State Highway Administration has given DNR about $11,000 to help state biologists preserve the rare plant. But road-salt runoff from the highway is a continuing concern for the Harperella that grows directly downstream.
An even greater concern may be the acidic rain that falls in Western Maryland and much of the rest of the state. Bartgis said that Sideling Hill Creek so far has not been affected, but it has very little natural capacity to neutralize acid rain produced by emissions from power plants, autos and other industry. Studies have shown that Harperella cannot stand acidic water or other pollution, he explained.
Maryland and Pennsylvania officials and the Nature Conservancy are moving to protect Sideling Hill Creek along its length.
Besides the Scout camp purchase, Maryland officials also are considering designating about 1,000 acres of the neighboring wildlife management area as "wildland," a state wilderness area where logging, road construction and other major disruptions would be barred.
Under today's deal, the Scouts can continue to use the camp they have owned since the 1950s. The Maryland National Guard, which has been conducting training exercises at the camp under contract with the Scouts, also will be allowed to keep using it.
The Guard's activities will be restricted to prevent disturbance of the stream, state officials say.
"This is an absolutely win, win, win situation," said Joseph Charles Jacobs, president of the Baltimore Area Council of the Boy Scouts of America.
The Boy Scouts and the Guard can continue to use the property, Jacobs noted, while Marylanders are "now guaranteed that this wonderful wilderness will be available to them forever."