Vegetation of the Brucker Marsh and the Barn Island Natural Area, Stonington, CT.

Document Type

Honors Paper


William Niering

Publication Date



Master's thesis from 1966. Held by the University of Connecticut. An additional hard copy of this thesis is in the Linda Lear Center for Special Collections and Archives.


The two study areas, the Brucker Marsh and the Barn Island Natural Area, are located in the Barn Island Game Management Area owned by the State of Connecticut. The Brucker, an unimpounded natural valley marsh, displays a series of different vegetation types and generally decreasing salinities from bay to upland. The tidal marsh along the bay front is replaced by a brackish cattail marsh which is then replaced by a shrubby fresh-water swamp. The hurricane of 1938 destroyed an open red maple forest originally found where the cattails are now dominant. This storm also killed many large maples once found in the Shrubby Swamp itself.

In the tiday marsh a Spertina Alterniflora Low Marsh Community (20 parts per thousand) nearest to the bay is replaced by a very saline (25 p/T) Flooded Penne, giving way to a Spertina patens High Marsh Community (5 p/T). In the High Marsh, marsh elder (Iva oraria) forms a belt along the mosquito ditches. A switch grass (Panicum virgatum) belt borders the upland. On areas bared by erosion (the Eroded Edge), various forbs and spike grass (Distichlis spicata) are predominant. Black grass (Juneus Gerardi) is rare in the tidal marsh. Salinities of the cattail marsh and the Shrubby Swamp are 1.5 p/T and 0 p/T, respectively.

Studies of the past documented coastal submergence and the encroachment of the tidal marsh over the fresh-water sediments. This is resulting in a gradual shift of all vegetation belts landward. Each vegetation type within itself appears to be relatively stable.

Productivity studies in the Brucker tidal marsh show that Spartina patens yields the greatest biomass per area at 660 gm./m2. Spartina alterniflora averages 480 gm./m2, and the lowest production is found in the ford-covered Eroded Edge at 200 gm./m2. The probable average figure for the total marsh is about 500 gm./m2, which is one-half ton of dry material per acre.

The Brucker Marsh is unique for studying the effects of coastal submergence and various storms on a salt marsh to fresh-water swamp vegetation gradient and has the added benefit of being State-owned, but does not yet have the protection of being a natural area.

The Barn Island Natural Area include a tidal marsh and three upland islands. The former is somewhat similar tot hat of the Brucker; the marsh vegetation types include Spartina alterniflora Low Marsh, Spartina patens High Marsh, and the Forb Panne. This is one of the few places in the Barn Island marshes where the patens community still retains some importance; within the High Marsh is found a Juneus Phase, lacking in the Brucker,

The upland islands, formerly cleared for agriculture but since abandoned, are mainly covered by shrubby thickets. On Barn Island a relatively stable shrub community dominated by bayberry (Myrica pensylvanica) covers the greater part of the area. A small open-grown Oak Woodland is reproducing rather ineffectually and may eventually be replaced by the vigorous shrub clones. A few limited Herbaceous Openings covered with goldenrods (Solidago sp.) and broom sedge (Andropogon scoparius) are slowly being invaded by dwarf sumac (Rhus copallina) and bayberry. Around the edge of the island occur belts of Iva, goldenrods, and sweet pepper-bush (Clethra sinifolia); these are largely discontinuous. On Barn Island salt spray, severe storms, and shrub competition are among factors limiting the presence of other species.

The tidal marsh vegetation exhibits an exceptional spectrum of the varied vegetation types described by Miller and Egler (1950) for this region. On Barn Island the clonal bayberry development is unique in its extensiveness and stability. The Barn Island Natural Area offers unusual opportunities for continued ecological research.



The views expressed in this paper are solely those of the author.