Wetlands, Marshes and Swamps

Marshy area near a meadow with trees
Great Meadow Wetland is one of many wetlands in Acadia National Park that serve as habitats for plants and animals as well as beautiful views for humans. NPS Photo/Kent Miller

NPS photo by Kent Miller

Over 20 percent of Acadia is classified as wetland. All classes of wetlands (swamps, marshes, and bogs) are found within the park. Some are freshwater, meaning they are fed by freshwater streams. Others are saltwater marshes which are located along inlets from the ocean. They all form the transition between land (terrestrial) and water (aquatic) environments.

Even though they only make up about 7% of Acadia’s landscape, freshwater wetlands are home to a whopping two-thirds of Maine’s state-listed rare plants that occur in the region. They maintain biodiversity by providing a habitat for a wide range of species. Resident animals visit wetlands alongside species that are nesting, overwintering or migrating, such as birds along the Atlantic flyway. More than half of Maine's state-listed rare plants are found in wetland habitats, and at least one rare plant is found in each Acadia wetland type. Freshwater plants such as sedges and grasses support many Amphibians and reptiles and insects.

More Than Meets The Eye

Not all of Acadia's wetlands are healthy. Poor sites, such as Great Meadow, have many invasive plant species (like glossy buckthorn), poor soil and water drainage. Climate change is further stressing wetland environments with warming temperatures, harder and more severe rain events combined with droughts, and changing seasonal rhythms.

Together with our partners-in-science, Acadia park staff are studying these wetlands to inform park management decisions as to how to best preserve them for future generations.

blue sky and clouds reflecting in water with mountain in the back
The outlet of Great Meadow Wetland creates a beautiful view, but it is actually the result of reduced stream drainage by road culverts.  NPSPhoto.

Great Meadow Wetland

Located adjacent to the Park Loop Road and the Sieur de Monts Spring area, the Great Meadow Wetland is part of a larger network of wetlands, streams, and ponds in the Cromwell Brook watershed, including the Tarn. Nestled at the base of Dorr Mountain, Park founder, George B. Dorr, focused much of his attention on this area and greatly modified it, adding greenhouses, trails and roads. This, coupled with prior modifications, greatly altered the flow of water through the wetland, impairing its ability to act as a wetland and allowing non-native species to thrive instead of freshwater plants.

Together with its partners-in-science, Acadia is working to restore natural water flow into the wetlands and remove invasive plants. Learn more about our work to restore the health of the Great Meadow Wetland.

sunset reflected over green grass and stream
The sun sets on Bass Harbor Marsh in Acadia National Park. Photo by Ashley L. Conti/Friends of Acadia.

Bass Harbor Marsh

Bass Harbor Marsh is located on the western side of Mount Desert Island and is the largest area of salt marsh in Acadia. A small estuary is formed where freshwater streams meet the sea, with brackish (part saltwater, part freshwater) conditions influenced by the twice-daily tides. Bass Harbor Marsh has been severely impacted by invasive plant species that have displaced the native species that support a greater diversity of wildlife.

Together with our partners-in-science, Acadia National Park scientists and volunteers are actively working to remove the problematic plants and restore the health of Bass Harbor Marsh. Learn more about Bass Harbor Marsh.


More About Acadia's Wetlands and Marshes

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    Last updated: May 10, 2024

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