Delaware Wetland Types Salt Brackish

Delaware’s landscape is rich in variety of wetland habitats with each type supporting unique communities of plants and animals. Tidal What follows is a list of the most prominent kinds divided between salt to brackish marshes and seasonal freshwater wetlands.

Salt and brackish marshes cover Delaware’s coast from the upper margins of Delaware Bay south to the Inland Bays. Flooded twice daily by tidal waters carrying salt water from the ocean and bay, these habitats are strongly influenced by salinity - becoming less salty the further up bay, river and stream. Dense stands of Spartina grasses characterize the treeless landscape. A more varied flora and fauna can be found as the water becomes less salty.

Salt marshes provide critical nursery habitat for fish and shellfish, vital resting areas for migratory waterfowl and wading birds, and protect us from impacts of coastal storms and floods. Historically, many coastal marshes were drained or ditched for agriculture or mosquito control. Restoring tidal flow is a key restoration focus. Unexplained vegetation dieback is a current concern. Freshwater tidal wetland

Freshwater tidal marshes are becoming rare in Delaware due to salt water intrusion from sea-level rise, with the best remaining examples occurring upstate along the Christina River and downstate along the upper reaches of the Nanticoke. Like salt and brackish marshes, they are flooded daily with tidal inputs, but are so diluted by freshwater sources that their salinity levels are negligible. These conditions foster a high diversity of wetland plants, including: spatterdock, pickerelweed, arrowhead, cattail, wild rice, water-willow, buttonbush and others.

Because freshwater tidal marshes have become scarce, and since what remains supports numerous rare and threatened plant species (many of which are being displaced by invasives such as Phragmites), these habitats merit a high priority for preservation and restoration. Scrub shrub wetland

Scrub-shrub wetlands may occur as isolated wet thickets fed by seasonal high water tables (non-tidal situations) or in tidally-fed river bank areas along coastal waterways (e.g. Spring Creek, Cedar Creek, and the St. Jones, Murderkill and Broadkill Rivers). As the name implies, shrubs are prominent in the flora, including: buttonbush, red maple, black willow, smooth alder, marsh elder, high-tide bush, and others, the mix depending on the level of salinity influence.

Scrub-shrub wetlands help stabilize stream banks and provide cover for birds and other wildlife. Although not as strongly impacted by human activities as many other wetland habitats, certain scrub-shrub wetland subtypes (red maple/ash tidal swamps and smooth alder/silky dogwood swamps) are listed as habitats of special conservation concern in Delaware. Atlantic white cedar swamp

Atlantic White Cedar swamps can be found mainly in Sussex County, where they occur in poorly-drained, acidic, highly organic soils, either along river floodplains (including Cedar Creek, the Mispillion River and the Nanticoke River), or in the headwaters of mill ponds. They feature a white cedar tree canopy with deciduous (typically maple/gum) trees mixed in. A unique community of sphagnum moss and carnivorous plants occupies the forest floor.

Prior to extensive timbering and drainage during the 1800’s and 1900’s, white cedar swamps were abundant in Delaware, including hundreds of acres within the Great Cypress Swamp. Though now scarce in Delaware, cedar swamps provide critical habitat for certain species (sundews, pitcher plants, dragonflies, salamanders, etc.) found in few other places in the state.

Bald Cypress swamps in Delaware are the northernmost examples in the United States, and thus comprise an especially unique ecosystem to this region. Easily distinguished by the presence of the evergreen, knobby-kneed Cypress trees, these swamps can be found within forested floodplains of some southern Delaware rivers and creeks, including the James Branch near Trap Pond, Trussum Pond, the Great Swamp, and a small stand near Killens Pond.

In addition to supporting unique plant and animal communities and providing wetland benefits to the watershed, Delaware’s Bald Cypress swamps are among the most scenic and serene places to explore by canoe or kayak, with Trap Pond State Park being a prime point of entry.

Photographs courtesy of the DE Natural Heritage Program and DE Watershed Assessment Section.

DNREC : Admin : Delaware Wetlands : Delaware Wetland Types Salt Brackish

Wetland Types of Delaware