This assessment of Scarborough Marsh found that despite a long history of intensive human use including tide gates that cut off tidal flows, farming, ditching, and development of the surrounding uplands, although far from a pristine condition, in many ways the ecological integrity of the marsh is better than it has been for almost 100 years. This is primarily due to the removal of tide gates and the opening of a new channel in the Eastern Road in the 1950’s and the removal of a tide gate at Jones Creek near Pine Point. However, significant differences in the vegetation on either side of Pine Point Road and either side of the Eastern Road suggest that the tide gates created permanent changes in the marsh. The primary physical change identified by this study is the lower marsh surface elevation on the inland side of the marsh due to decay of marsh peat during the time that the tide gates were functioning. Similar effects were found by Linnel (1994) where Black Point Road crosses the Libby River. The rapid growth of Common Reed (Phragmites australis) in the vicinity of Route 1 and in other parts of the marsh (especially Cascade Brook just seaward of Blue Point Road and in the Jones Creek marsh) is resulting in a loss of open marsh habitat for ducks, geese, egrets, herons, and other wading birds. Although there are only 50-60 acres of Phragmites in the entire 3,000-acre marsh system at this time, the area of Phragmites in the vicinity of Route 1 increased by approximately 50% in 10 years. Because of its aggressive nature, this plant should not be ignored.

Extensive ditches affect parts of the marsh (see Section VI), but in many cases they promote tidal exchange and probably help to control the spread of Phragmites. While plugging ditches can enhance habitat for some wildlife species, restoration of adequate tidal flows to restricted sections of the marsh and control of Phragmites should take precedent over ditch plugging and associated habitat enhancement.

Specific recommendations, based on the findings of this study, for monitoring and restoring Scarborough Marsh are discussed below.

The Phragmites stands in the vicinity of Route 1 have been identified as a concern by the Maine Department of Inland Fisheries and Wildlife, the National Oceanographic and Atmospheric Administration, and the US Fish and Wildlife Service. These agencies have considered restoration of natural marsh conditions by eliminating or reducing the amount of Phragmites on the inland side of Route 1. Our study confirms that this is the highest restoration priority within the marsh system. Our analysis of Phragmites (Section IV) as well as tide and marsh elevations (Section V) suggests that a restoration plan encompassing multiple elements will be necessary. Phragmites control in this area should consider:

1. additional culverts to increase tidal flow under Route 1;
2. a system of ditches to improve tidal flushing where Phragmites is most aggressive, thereby minimizing freshwater influence; and
3. the level of nitrates in the watershed and, if necessary, steps to control its influence.

While our study found problems and suggests possible solutions, the recommendations should be considered preliminary in nature. Additional research will be needed to create the best management plan for this area. The Maine Audubon Society strongly recommends that state and federal agencies listed above continue to work toward a solution to this problem.

Our studies found that the Jones Creek marsh has a severe tidal restriction, large Phragmites stands, and a significant area that has reverted to freshwater marsh. The existing Pine Point Road culvert and ditch that flows through the former Snow’s Chowder factory is a significant barrier to tidal flow. Tidal flows to this marsh might be significantly improved by cutting a new channel that would cross Pine Point Road about 0.3 miles south of the current culvert. This could result in restoration of about 75 acres of tidal marsh south and east of the Boston and Maine Railroad, including aver 30 acres of former salt marsh that is now freshwater wetland and enhancement of approximately 40 acres of existing salt marsh with improved tidal flushing. Additional restoration may be possible beyond the railroad. Additional studies are recommended at this site to further evaluate the potential for restoration. The Maine Department of Inland Fisheries and Wildlife, the US Fish and Wildlife Service, and other parties(e.g., Ducks Unlimited, Maine Department of Transportation) could cooperate on this project.

The culvert width where the Libby River crosses under Black Point Road is only 18% of the river width, the lowest percentage of any restriction in the Scarborough Marsh system. A previous study by Linnell (1994) found that the marsh was drier, its elevation and salinity lower, and the plant community different on the inland side of the restriction. Placing additional culverts in the river channel at this point would enhance tidal flows to almost 60 acres of salt marsh, possibly reducing or eliminating Phragmites just inland of the road and allowing salt marsh vegetation to replace brackish-marsh vegetation (Narrow-leaf Cattail and Bulrushes) further inland. The Maine Department of Inland Fisheries and Wildlife, US Fish and Wildlife Service, and the Maine Department of Transportation could cooperate on this restoration project.

Anecdotal evidence suggests that Phragmites was almost non-existent in the marsh 25 years ago but that it is now spreading rapidly. A study conducted by a student at the University of Southern Maine documented rapid growth in the vicinity of Route One. We recommend a monitoring project that would:

1. monitor the spread of selected Phragmites stands covering a representative range of marsh conditions to provide better estimates of growth rates (as measured by stand area), and
2. repeat the Phragmites assessment summarized in Section IV after 5 years (in 2003) to see if new stands have appeared or existing stands have significantly increased in size.

The monitoring could be undertaken as part of a scientific research project and/or with the help of volunteer monitors.

There are many diverse groups and individuals with a keen interest in the ecological well being of the Scarborough River estuary. Duck hunters, fishers, clam diggers, boaters, birdwatchers, and others use the estuary on a regular basis; for some it is their major source of income. In addition, there are many conservation organizations involved in one way or another with the marsh, including several town boards, state agencies (including the Department of Inland Fisheries and Wildlife, the owner of most of the marsh), federal agencies, and private non-profit groups such as Maine Audubon. However, these groups typically focus on one aspect of the marsh (e.g. water quality sampling or wildlife management), while none typically looks on the entire marsh system and the watershed that feeds it. Ultimately, maintaining and restoring the ecological integrity of the marsh will require a broad watershed-based constituency and an organization that can help build on and integrate the work of the various groups with an interest in marsh conservation. While this study is the first to systematically evaluate the entire marsh system, it is still limited in scope and there is much follow-up work to be done. Maine Audubon initiated this study because of the statewide significance of the marsh and its long-term interest in the marsh through the Scarborough Marsh Nature Center. However, the interests of Maine’s largest salt marsh will be best served by a watershed-based organization whose sole focus is conservation of Scarborough Marsh and its estuary system.