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

Bringing Back Native Plants


The Mount Vernon Gazette, Connection Newspapers, published an article on our native plant restoration project.  You can read it here

Our partners are the National Park Service, Earth Sangha and the Audubon Society of Northern Virginia.  We also appreciate support from the National Environmental Education Foundation and Transurban.

Sign up to help us control invasive plants and make this project a success at This email address is being protected from spambots. You need JavaScript enabled to view it..

Dyke Marsh’s Submerged Aquatic Vegetation

Dr. Rybicki

Several FODMers learned about native and non-native submerged aquatic vegetation (SAV) of Dyke Marsh and the Potomac River on July 14, 2018, when Nancy Rybicki gave a tutorial and led a paddle.  Dr. Rybicki is an aquatic plant ecologist and wetlands scientist, retired from the U.S. Geological Survey.  In her 37 years of studying the vegetation of the Potomac River, she has correlated the presence of submerged aquatic vegetation with water quality.

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Butterflies, Dragonflies, Damselflies Delight

Needham's skimmer

On a beautiful, 82-degree, breezy July 7, 2018, 15 FODMers studied butterflies, dragonflies and damselflies and their host plants in the Dyke Marsh Wildlife Preserve and Belle Haven Park.

It was a Needham’s skimmer (Libellula needhami) day. These showy dragonflies were whizzing around everywhere and eating midges, making for easy sightings.  The males are bright reddish-orange and have a red face.  The females are yellow and black.  Both sexes and all ages have a black line on their abdomens and orange-tinted wings.

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Exploring the Ecology of Dyke Marsh

Charles Smith

On June 9, 2018, Dyke Marsh members and friends learned about Potomac River wetland ecosystems and the interrelationships of plants, insects, birds and other biota, on a walk on the Preserve’s Haul Road trail led by Charles Smith, expert naturalist and Chief of Fairfax County’s Stormwater Planning Division, Watershed Projects Implementation Branch. He also discussed human intervention and how native Americans used some of the marsh plants.

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Restoring Habitat – 2,000 Native Plants

Matt Bright

On June 9, 2018, twenty volunteers and National Park Service staffers planted another 1,000 native plants on a cleared .65-acre site along the Haul Road trail.  The site was previously overrun with non-native or invasive plants, like English ivy, mile-a-minute and stiltgrass.

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Reaching Out to Neighbors


The Friends of Dyke Marsh shared a table with the Friends of Huntley Meadows Park on June 16, 2018, at the annual Community Day in Gum Springs, a historically African-American community near the Dyke Marsh Wildlife Preserve.

FODMers Catherine Noonan and Mary Luceri greeted many festival-goers and helped youngsters make colorful birds.  T-Rex and his “friend” dropped by and entertained all.  The event drew 32 vendors and organizations, elected officials, a steel drum band and many guests.

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Battling Invasives, Protecting Natives

Brent Steury

Keeping non-native, invasive plants out of the native plant restoration area along the Haul Road trail is a long-term challenge and efforts began on June 5, 2018, when ten volunteers participated in a training led by National Park Service (NPS) biologist Brent Steury.  Brent stressed that the two priority plants to try to control are Japanese stiltgrass (Microstegium vimineum) and mile-a-minute (Polygonum perfoliatum).  He urged volunteers to pull them out of the ground before they set seed.  “If they set seed, we’ve lost,” he stressed.

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Bald Eagles Fledged in Early June

eagle nest

There were three active bald eagle (Haliaeetus leucocephalus) nests in the Dyke Marsh Wildlife Preserve this year, 2018.  We will soon report the number of eaglets that successfully fledged. During the week of June 4, “our” eagles, this year’s birds, left the nest.  Many visitors enjoyed observing them, especially those nesting near the Haul Road trail.

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Wildlife Adapt to Flooding Tides


In the spring of 2018, the combination of heavy rains, easterly winds and normal tidal fluctuations due to the moon’s and sun’s gravitational effect created flooding tides in the wetlands of the Dyke Marsh Wildlife Preserve.  Visitors saw  mammals, birds, reptiles, insects and crustaceans foraging on or near the shores and tidal guts.  Some altered some of their foraging patterns, moving to the trails or higher ground than they normally use.  Observers saw abundant land snails climbing cattails and other marsh vegetation. 

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Studying Skinks in Dyke Marsh


Dyke Marsh visitors have had some good skink sightings this spring 2018.  A skink is a type of lizard, typically shiny and with short or no limbs.  Most skinks have tapering tails that they can shed if predators grab them and they usually can regenerate the lost part of the tail. Skinks move quickly.

Virginia has nine native lizard species, according to Alonso Abugattas, Arlington County Natural Resources Manager.   Six of these species are likely in the Washington, D.C., region.  “All lizards native to Virginia in the genus Plestiodon have bright blue tails as juveniles/subadults,” according to the Virginia Herpetological Society’s website.

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Volunteers Restore Habitat in Dyke Marsh


On May 9, 2018, 20 dedicated volunteers and National Park Service (NPS) staffers planted around 1,500 native trees and plants on .65 acres on the west side of the Haul Road trail in Dyke Marsh.  Among others, the group planted spicebush and winterberry; trees included sycamore, tulip tree, cottonwood, maples and black gum; "phorbs" included wing stem, pyeweed, tick-trefoil and moonflower vine plus grasses such as deer-tongue, Virginia rye and riverside rye.

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Volunteers Test Water Quality

water test

Determining the habitat quality of a stream flowing into Dyke Marsh from the west was the quest on May 5, 2018, when FODM volunteers conducted some biological testing of the stream flowing through Mount Vernon District Park.  FODMers partnered with the Westgrove Dog Park PACK organization and led by Dan Schwartz, Northern Virginia Soil and Water Conservation District, took 20 samples from the stream within a 300-foot span, with the goal of identifying 100 living invertebrates. The group found 55 invertebrates, fewer than the desired 100.  Forty of the 55 were scuds, considered to be impairment tolerant organisms.

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