McIntosh Run and Dwarf Mussels
McIntosh Run. Dan Murphy, USFWS
McIntosh Run. Dan Murphy, USFWS

Funding has been secured to purchase a conservation easement to protect 85 acres along McIntosh Run in Maryland. McIntosh Run is located in a region known as “Southern Maryland,” which, because of its proximity to expanding military bases and Washington, D.C., is the fastest growing geographic region of the State.

The McIntosh Run watershed is currently one of the most ecologically intact watersheds remaining in Maryland, containing large blocks of contiguous forest, which provide habitat for forest interior birds and other wildlife in addition to insuring that water quality in the stream is adequate to support the aquatic life.

Dwarf wedge mussel (Alasmidonta heterodon)
U.S. Army Corps of Engineers
Dwarf wedge mussel (Alasmidonta heterodon) U.S. Army Corps of Engineers

The protected property contains a population of the Federally and State-endangered dwarf wedge mussel (Alasmidonta heterodon) as well as 12 State listed species. The property also supports an active Federally-threatened bald eagle (Haliaeetus leucocephalus) nest.

The dwarf wedge mussel has declined precipitously in the past hundred years. There were originally 70 populations of dwarf wedge mussel known throughout North Carolina to New Brunswick. That number has since dwindled to 20. As a result, it was listed as Federally-endangered in 1990. In Maryland, the dwarf wedge mussel is now known to occur in four drainages.

Rural barn. Dan Murphy, USFWS
Rural barn. Dan Murphy, USFWS

Habitat loss is considered to be the most significant cause of mussel declines in McIntosh Run and other Maryland streams. Forested buffers have been maintained along most of the stream sections in the core area of McIntosh Run, however impacts from grazing and agricultural run-off are likely impacting mussels to some extent.

Since 1995, there has been a significant increase in the construction of new homes, strip malls, and offices in the watershed. These developments are frequently associated with impermeable surfaces which result in increased non-point source run-off containing gasoline, oil, anti-freeze, nutrients, and pathogens into streams, reducing water quality.   

This effort is the first step in a process that will preserve at least 1,680 acres in the watershed to insure the future of the McIntosh Run dwarf wedge mussel population, protect one of the most ecologically intact watersheds remaining in Maryland, and ensure that water quality remains high.

Box turtle. Dan Murphy, USFWS
Box turtle. Dan Murphy, USFWS

This conservation effort is the work of the McIntosh Run Land Conservation Partnership, which includes St. Mary’s County, Patuxent Tidewater Land Trust, the town of Leonardtown, The Nature Conservancy, Maryland Department of Natural Resources, Maryland Department of Agriculture, Potomac River Association, U.S. Army Corps of Engineers and U.S. Fish & Wildlife Service. For more information, contact:

Dan Murphy
U.S. Fish & Wildlife Service
(410) 573-4521
dan_r_murphy@fws.gov