Friends of Dyke Marsh is a volunteer group dedicated to preserving, restoring and enhancing Dyke Marsh, a freshwater tidal marsh in Fairfax County on the Potomac River just south of Alexandria, Virginia. The Dyke Marsh Wildlife Preserve is administered by the National Park Service.

What Is Dyke Marsh?

The Dyke Marsh Wildlife Preserve is a freshwater, tidal marsh on the Virginia side of the Potomac River in Fairfax County. It is a unit of the George Washington Memorial Parkway, U.S. National Park Service. For more information, visit the NPS website at

FODM Honored by Virginia Legislature

General Assembly

The Virginia General Assembly passed a resolution recognizing the work of the Friends of Dyke Marsh, FODM's 40th anniversary and the 100th anniversary of the national parks system in 2016. The bill's patrons were Senators Scott Surovell and Adam Ebbin and Delegates Paul Krizek and Mark Sickles.

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NPS Gives FODM an Award


The National Park Service (NPS) gave the Friends of Dyke Marsh an award in recognition of FODM’s “exemplary service and dedication to the George Washington Memorial Parkway” on August 25, 2016.  Alexcy Romero, Superintendent of the George Washington Memorial Parkway (GWMP), presented the award, a wooden plaque in the shape of the NPS arrowhead symbol, to FODM President Glenda Booth at Fort Hunt Park during an employee recognition event.

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FODMers Learn about Plants from an Expert

Dr. Wells

            On Saturday morning, September 3, 2016, as Hurricane Hermine pounded Virginia’s coast, 25 FODMers studied the plants of Dyke Marsh on a windy, “rainless,” three-hour walk.   “At least there’ll be fewer mosquitoes,” quipped walk leader Dr. Elizabeth Wells, Associate Professor Emerita of Botany at the George Washington University.  Her commentary was engaging and wide ranging, covering plant taxonomy, reproduction, structure, pollination, predation, host plants and more.

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STEM Students Visit Dyke Marsh

Emmet Rosenfeld

On July 14, 2016, FODM hosted 25 George Washington Middle School students participating in the Alexandria Public Schools’ summer STEM (science, technology, engineering and mathematics) program and two of their teachers.  The students learned about the natural resources of Dyke Marsh and conducted some water testing using seine nets. 

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Snake Sightings

Northern watersnake

Two species of snake are often seen in Dyke Marsh in the summer.

On July 1, 2016, during a canoe trip in the southern part of Dyke Marsh, FODMers saw an encounter between a common water snake (Nerodia sipedon sipedon) and a catfish.  Also called the northern water snake, it is probably the most abundant snake in Dyke Marsh.

These photos (by Ed Eder) indicate how the prey was snared in deeper water and dragged to the shore by a very determined snake.  

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FODMers Help With National BioBlitz

Goldenrod crab spider

During the May 20 and 21, 2016, national BioBlitz, FODMers, National Park Service (NPS) staff and friends identified 13 new spider species in the Dyke Marsh-Belle Haven Park area. Other records for Dyke Marsh: the first spring record for a Philadelphia vireo (Vireo philadelphicus); the second record for the hoary bat (Lasiurus cinereus); one new earthworm (Bimastos palustris), a native species; and two new terrestrial isopods (Porcellio laevis, Trichoniscus pusillus).  At our “sister” park, Theodore Roosevelt Island, people found 17 new lichens.

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Spring Brings Breeding Skinks


Spring is breeding time in Dyke Marsh for many species of wildlife, including skinks. The American five-lined skink, (Plestiodon fasciatus), is one of the most commonly seen lizards in eastern North America and is frequently observed around logs along the Haul Road Trail (photo, skinks mating May 2016 by Ed Eder). 

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The Interdependence of Natural Resources


At the quarterly meeting of FODMers and friends on May 11, 2016, Alan Ford and Laura Beaty gave a presentation on the interrelationships of plants and animals and the important role of pollinators and leaf-eaters.  Alan is president of the Potowmack Chapter of the Virginia Native Plant Society and Laura chairs the Propagation Committee.

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Ospreys Are Resourceful, but Fishing Line Is a Danger

great blue heron

Every spring, FODMers welcome the spring return of the ospreys (Pandion haliaetus) to Dyke Marsh and the Potomac River shoreline where these magnificent raptors build and refurbish their nests and raise their young.   In recent years, there have been approximately 10 to 12 active osprey nests within FODM’s breeding bird survey tract, a three-mile area that extends from the Porto Vecchio condominiums near Hunting Creek to south of Morningside Lane.  

Despite the rebound in the osprey population, threats still exist. 

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T.C. Williams Students Visit Dyke Marsh

Canada geese

On the morning of April 29, 2016, 24 students and three teachers from Alexandria’s T.C. Williams High School’s International Academy visited Dyke Marsh to observe in action some of the lessons of their biology class and to try their hand at suppression of invasive plants. 

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Lepidoptera and Odonata Surveys Underway


Volunteers began lepidoptera and odonata surveys in Dyke Marsh on April 20, 2016, led by Jim Waggener. On the 20th, surveyors identified five butterfly species in a brief span.  The peak time for surveys is May through September. This work helps identify and save critical habitat that preserves biodiversity in our region. 

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