Restoration Priority

<div>Coastal wetlands are critical to the productivity and diversity of marine ecosystems
and to the human economies they support. The Northeast and Mid-Atlantic regions of
the US include thousands of coastal wetlands, with the shoreline characterized by salt
marshes, tidal flats, beaches and dunes, and a wide variety of river deltas, sounds,
inlets, and estuaries. Yet many coastal counties are experiencing significant population
growth, and with estimates of sea level rise projected up to six feet by the next century,
it is likely that many wetland habitats and their ecosystem services will be lost. The
characteristics of some coastal wetlands make them more likely to be resilient and
remain diverse and productive even as they adjust to climate-induced changes. In this
project, we mapped these characteristics and estimated the relative resilience or
vulnerability of 10,736 coastal sites from Maine to Virginia. </div><div><br /></div><div>Technical methods for mapping and estimating coastal resilience were developed in
concert with a steering committee of 35 coastal experts that included members of the
U.S. Fish and Wildlife Service (USFWS), representatives from the National Oceanic and
Atmospheric Association (NOAA) and other federal, state and NGO staff from both
Northeastern and Southeastern states. We divided the coast into 10,736 individual
sites centered around each tidal marsh or complex of tidal habitats over two acres. For
each site, we estimated the amount of migration space available under six sea-level
rise scenarios and we identified the amount of buffer area surrounding the tidal
complex. We then examined the physical properties and condition characteristics of
the site using newly developed analyses as well as previously published and peer-reviewed datasets. For tidal complexes, the physical factors assessed included the size
and tidal zone diversity of the migration space, the size and shoreline intricacy of the
existing tidal complex, and the amount of shared edge between the tidal complex and its migration space. Condition factors included the amount of hardened shoreline, as
well as the magnitude of nitrogen inputs, and the quantity of sediment and freshwater
inputs. For the buffer area, we assessed its size and variety of compatible landforms
and soils, the connectedness of its wetlands, and the amount of natural cover. A score
was calculated for each site based 80% on the tidal complex and 20% on the buffer,
with equal weight given to physical and condition characteristics. Scores were
calculated for each of six sea-level rise scenarios (1 to 6 ft.). Our final maps were based
on the 6-foot scenario because this scenario reveals the sites with the greatest long-term potential for adaptive response. We made the 6-foot results even more robust by
slightly boosting or penalizing the score based on whether the size of the migration
space showed a significant increasing or decreasing trend over the 3-6 foot scenarios.</div><div><br /></div><div>The scores are presented relative to other complexes within one of five coastal
shoreline regions. Coastal shoreline regions are geographic areas where the coasts and
estuaries are dominated by a common set of processes and geomorphology (e.g.,
drowned river valleys, lagoons, embayments). The scores are presented in
standardized normalized values (z-scores), which are units of standard deviations
above or below the mean score of all sites in the coastal shoreline region. For example,
a z-score of 3 SD for a site in the lagoon shoreline region indicates that the site score is
three standard deviations higher than the average score for all lagoon sites.</div><div> <br /></div>Resilience Z-score, Condition Z-score, Physical Z-score and Shoreline units of the Northeast U.S. and Mid-Atlantic States. Ecosystem, population, ecoregional portfolio, restoration priorities, shoreline type, nitrogen levels, &amp; sediment loads also portrayed.<div><br /></div><div>For more information see the <a href='https://easterndivision.s3.amazonaws.com/coastal/Resilient_Coastal_Sites_for_Conservation_NE_Mid_Atlantic.pdf' target='_blank' rel='nofollow ugc noopener noreferrer'>Resilient Coastal Sites for Conservation in the Northeast and Mid-Atlantic report</a></div>