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The coastline of the Northern Appalachian /Acadian ecoregion extends for 7,453 miles and is rich with almost 24,000 examples of beaches, salt marshes, tidal flats and distinctive rocky shores. Although coastal wetlands and shores cover less than 1% of the ecoregion (926,664 acres -Table 1) they are one of the most critical habitats in the region for biodiversity. Their importance to rare species, shore birds, and offshore fisheries is well known but population trends and conservation needs of the thousands of specialized organisms, (crabs, shellfish, amphipods and other macro/micro invertebrates) are not clearly understood.

The distribution of coastal features within the ecoregion is correlated with shoreline orientation, exposure and complexity and tidal range. The complicated south-facing shorelines of Maine and Nova Scotia have extensive tidal flats and salt marshes tucked into nearly every cove and harbor (Figure 1). In contrast, the simpler shorelines that flank the Bay of Fundy have fewer examples of these features but terminate with massive tidal flats in the Cobequid Bay and Minas Basin region reflecting a tidal range that is the largest in the world. The east facing shores of New Brunswick and PEI have extensive barrier beaches and dunes while Quebecs beaches and dunes are almost entirely located on the Magdalen Islands.

Coastal Zone and Important Bird Areas.

The unique importance of coastal shores, marshes, offshore waters or isolated islands to shorebirds has long been recognized. Many places in the ecoregion have been ranked globally and/or nationally significant for shorebird or seabird concentrations and threatened species. Some of the most important include:

 Northeast Coastal Maine (ME)

 Country Island Complex (NS)

 Sable Island (NS)

 Eastern Cape Sable Island (NS)

 Cobequid Bay (NS

 Malpeque Bay (PEI)

 Southern Bight, Minas Basin (NS)

 Brier Island (NS)

 PEI National Park (PEI)

 Iles-de-la-Madeleine (QU)



Coastal Shore and Wetland Portfolio Summary

The screening criteria used to locate and identify coastal shore and wetland features most critical to maintaining biodiversity required that each qualifying occurrence:

 Was contiguous and met size criteria:

o Salt/Brackish marsh over 50 acres or part of a complex over 100 acres

o Beach/dune over 20 acres

o Coastal bogs over 75 acres

o Tidal flats over 100 acres or part of a larger complex

o Rocky shores and cliffs that were 2 acres minimum and part of a complex including some of the above features

 Were in good landscape settings (Land Cover Index < 30)

 Were in good condition based on ground surveys and expert opinion (corroboration by at least one source)

 Contain other confirmed biodiversity features (element occurrences)

Size criteria for the respective systems were determined by a literature analysis of minimum area requirements for the characteristic breeding species as well as information on the scale of specific disturbances. Additionally, we examined survey records for species and communities with documented occurrences in Northern Appalachian / Acadian coastal wetland complexes.

We used different minimum size criteria for different features. For salt marshes both the literature and evidence from ground surveys suggested that occurrences over 50 acres were more likely to contain rare plant and bird species than smaller examples. For beach/dune ecosystems the evidence suggested that 20 acres was adequate to ensure that the occurrence could serve as a coarse filter for characteristic beach breeding species such as piping plover. Similarly intertidal flats of 100 acres of greater appear to be adequate in size to serve the needs of many typical species.

Unlike the literature analysis, the patterns derived form the inventory data are correlative and do not imply cause. Additionally, our method of examining size relationships tended to underestimate the size of the whole wetland. For example a tidal marsh dissected by a tidal creek may be registered in our analysis as two discrete occurrences on either side of the creek. A breeding species occurring on one side will be associated only with the size of that half. To get around this limitation we developed a map of coastal complexes based on physical features that unified marsh, tidal flat, beach and salt ponds into a single wetland complex. When the size of the complex is examined relative to associated species the data suggest that many species prefer larger complexes and that those sizes are greater than the minimums derived from each feature individually.

We adjusted our selection criteria to take into account the size of the entire wetland complex as well as the sizes of the individual occurrences within the complex. This allowed some smaller features to be included in the portfolio if they were part of a large wetland mosaic.

Results

Our goal was to identify a minimum of 40 examples per sub-region in which they occur. This goal of 1440 individual occurrences totals to about 13 percent of all the coastal features in the ecoregion or an estimated 17% of all features by area (using the minimum size criteria). After examining the distribution of the occurrences across gradients, we redistributed the goal of 1440 across the sub-regions in proportion with the number of possible occurrences.

We identified 2311 critical occurrences in 90 key complexes. This is more than the number needed to meet our minimum goal, however many of these occurrences are sub-units of a larger complexes. We met or surpassed the specific goals for each sub- region except for beach/dune features in the Acadian Highlands, and Nova Scotia Hills.