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Chapter 2 - Coastal Ecosystemsmeasurements using LiDAR data when available. Lengthcan be reasonably measured from existing data sources.However, the width and height of beach/dune systemsare key aspects of beach size related to resilience that aremuch more difficult to measure without extensive mappingefforts derived from orthophotography or localizedgeologic studies.Appropriate adjacent habitatBeaches could be assessed using shoreline (e.g. ESI), estuarine(e.g. NWI), and land cover classifications in additionto elevation to indicate whether they are backed by aheadland, dunes, coastal wetlands, or forest types. Thosebacked by headland could be further characterized usinggeological data sources as to whether the headland is ofunconsolidated material (sand, mud, gravel, which presumablycould contribute to accretion of beach material)or bedrock.Presence/Absence of artificial barriers to natural beachmovementBarriers could be assessed using NOAA structures datafor piers, groins, and jetties, and NLCD or NOAACoastal Change Analysis Program (CCAP) Land UseLand Cover data for roads and houses on the beach-dune.However, these are generally out of date and incomplete.Some states in the region have recently completed or arein the process of completing coast-wide coastal structuresinventories. These datasets are likely to be the best approachto assessing this attribute on a regional basis. Forthe CSU analysis, the percent of total CSU length thatwas “man-made” was measured using ESI line type codingand, where this did not exist in Maine and Canada, byoverlapping EPA and Canadian Department of NaturalResources and Energy data.Shoreline Change Rates may be one of the most importantfactors in predicting beach resilience to sea level rise.Where local studies have been done or are underway theseshould be factored in.Tidal WetlandsSizeFor the CSU characterization described above, the area ofall tidal wetlands was calculated using GIS. Patches weregrouped according to an algorithm based on adjacency andhydrological connections (e.g. marsh patches on either sideof a tidal inlet or river) as above.Landward topographyThis parameter refers to the amount of adjacent landat less than 1 and 2 m elevation. For accuracy thiswould need to be calculated using LiDAR when available.Analysis of landward topography, that is, slope andamount of adjacent land under a particular elevation, isthe primary approach of most of the studies of sea levelrise impacts to coastal habitats cited above.Presence/absence of artificial barriers to upslopemovementThis parameter could be assessed using the NLCD orCCAP land cover data on natural versus developed covertypes plus a transportation layer. On a site-specific scalethese barriers can also be assessed in some areas by compiledmaps of hardened shorelines or by analysis of digitalorthophotos. These constraints to upslope migration arebuilt into some, but not all, of the site-specific models ofinundation (See U Arizona web-based model in additionto the SLAMM references).Longitudinal Connectedness UpstreamThere is no region-wide GIS dataset that would allowdetermination of natural or anthropogenic barriers to upstreammigration of fringing tidal wetlands or salt wedges.However, this parameter could be determined on a sitespecificbasis by consulting local datasets and examinationof aerial photos and contour and bathymetry maps.Putting It All TogetherAnalyzing key ecological attributes from beach and tidalwetland ecosystems can support the growing understandingof resilience. Weighting, combining, and ranking theseattributes to produce relative scales of resilience can furtherour ability to assess ecosystem structure and functionNorthwest Atlantic Marine Ecoregional Assessment • Phase 1 Report 2-51