Barn Island’s Legacy of Conservation

The greater Barn Island conservation complex, including CT DEEP’s Barn Island Wildlife Management Area and adjacent conservation land, is nearly 1,300 acres and provides habitat for 25 federal or state-listed endangered, threatened, or special-concern species. By many measures, the Barn Island area is one of the most significant natural areas on Connecticut’s coast. But this wasn’t always the case.

This story begins in 1931 when residents of the Town of Stonington attempted to control mosquitoes in the area. Without sufficient knowledge of the complexities of tidal marsh ecosystems, the town hired a contractor to construct a series of ditches to drain the marsh surface of tidal pools and other stagnant water where mosquitoes breed. An unintended consequence of this effort was a significant decline in the area’s biodiversity, including a reduction in waterfowl, shorebird, and wading bird use of the marsh.

Impoundment 1 at Barn Island supports healthy plant community
Impoundment I at Barn Island supports a healthy plant community. Photo by Sibel Güner

Such consequences led to an effort to restore waterfowl use at Barn Island. In 1943 the State Forest and Wildlife Commission received $15,000 from the Connecticut General Assembly to acquire land at Barn Island and to restore its biodiversity. After research and expert consultation, three dikes were constructed in 1946 (II, I, and III) and one more in 1947 (IV) to impound water to attract waterfowl. To some degree, this was successful—reports document increased waterfowl use of the area as compared use in the previous 15 years.

But like the mosquito ditching 15 years prior, construction of the impoundments had unanticipated consequences. In particular, salt-tolerant vegetation that had once thrived in the salt and brackish water marshes were displaced by less salt-tolerant native and non-native vegetation that thrive in freshwater and brackish waters. Areas of the marsh that were previously open water became dominated by narrow-leaved cattail and the invasive common reed, Phragmites australis. In 1978 CT DEEP installed culverts in impoundments I and II that would restore water flow to the marshes, carefully monitoring its results. Native vegetation and wildlife have returned to the area in significant numbers demonstrating the capacity of salt and brackish marshes to restore themselves by regulating tidal water exchange.

Continued research and monitoring have been conducted at each stage of the restoration process. Research data from Barn Island has made it an extraordinary resource for scientists, providing insight into long-term changes in tidal marsh vegetation and responses to restoration efforts over 60 years. For example, in 1946, scientist Allen G. Smith mapped the vegetation at Barn Island and created baseline data that would be invaluable in understanding wetland ecosystems. This rare pre-impoundment and restoration data marks the beginning of decades of monitoring and research that’s allowed scientists to analyze the impact of restoration efforts over extended periods of restoration. The information garnered from researchers, including many from the University of Connecticut and Connecticut College, is an outstanding resource for the study of marsh ecology and restoration.

One study of particular importance is an article published by William Miller and Dr. Frank Egler in 1950, entitled Vegetation of the Wequetequock-Pawcatuck tidal marshes, Stonington, Connecticut. This ‘seminal’ research established a new paradigm for tidal marsh ecology in southern New England.  On-going research at Barn Island continues to aid in the understanding of complex estuarine ecosystems.

An important estuarine habitat in Little Narragansett Bay was the submerged rooted and flowering plant known as eelgrass (Zostera marina). Once plentiful in the bay, it had been harvested to create insulation material for homes and cottages. These beds have been replaced by benthic algae and this change is likely the result of nitrogen enrichment from two sewage treatment plants that discharge into the Pawcatuck River.

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