Resilient Coastal Sites (Southeast Blueprint Indicator)

Reason for Selection The resilient coastal sites indicator seeks to capture features of salt marshes that are important for salt marsh species and ecosystem function both now and in the future. Many of these characteristics, like water quality and landform diversity, also serve as indicators of a site’s potential future habitat quality once the salt marsh is fully inundated and transitions to a new estuarine or marine habitat. Input Data * [Southeast Blueprint 2025 extent] * The Nature Conservancy’s (TNC) combined terrestrial and coastal [resilient sites for the conterminous U.S.] in geodatabase format ([resilient_sites_national.zip]), accessed 12-3-2024 Mapping Steps * To extract the coastal component of the analysis, reclassify the “type_des” field to assign “Marsh Migration Space”, “Tidal Complex”, “Additional Marsh Migration Space”, and “In sea level rise zone” a value of 1, and everything else a value of NoData. * Clip the TNC data to the bounding box around the Southeast Blueprint 2025 extent. * Reclassify the numeric resilience field into the standard deviation-based classes that TNC uses to display the resilience data in their viewer. Note: the “sea level rise area” class denotes locations that are not part of a current tidal complex or future marsh migration space, but are at risk of inundation under 6 feet of SLR. Because they are not current or future marsh, they are outside the scope of the coastal resilience analysis. TNC also does not score them in their terrestrial resilience analysis because they are likely to be inundated in the future. * -3502 = 0 (sea level rise area) * -4000 to ≤ -3503 or -3501 to ≤ -2000 = 1 (least resilient) * -2001 to ≤ -1000 = 2 (less resilient) * -1001 to ≤ -500 = 3 (slightly less resilient) * -501 to ≤ 499 = 4 (average/median resilience) * 500 to ≤ 999 = 5 (slightly more resilient) * 1000 to ≤ 1999 = 6 (more resilient) * 2000 to ≤ 3260 = 7 (most resilient) * As a final step, clip to the spatial extent of Southeast Blueprint 2025. Note: For more details on the mapping steps, code used to create this layer is available [in the Southeast Blueprint 2025 Data Download] under > 6_Code. Final indicator values Indicator values are assigned as follows: 7 = Most resilient 6 = More resilient 5 = Slightly more resilient 4 = Average/median resilience 3 = Slightly less resilient 2 = Less resilient 1 = Least resilient 0 = Sea level rise area Known Issues * This indicator does not account for the occurrence and timing of disturbance processes, like prescribed fire, which impact resilience. * Accretion rates were not incorporated into the marsh migration data. * TNC assessed sea-level rise under a slightly different range of scenarios in the Northeast and Mid-Atlantic region, compared to the Gulf of Mexico and South Atlantic regions. In the Gulf and South Atlantic, they used four scenarios: 1.5 ft, 3 ft, 4 ft, and 6.5 ft. In the Northeast and Mid-Atlantic, they used 1 ft increments ranging from 1-6 feet. This means that the data used in the portion of coastal Virginia covered by the Northeast and Mid-Atlantic analysis assesses marsh migration space under a slightly less extreme maximum sea-level rise scenario (6 ft vs. 6.5 ft). As a result, this indicator likely underestimates the extent of resilient areas in this portion of coastal Virginia. Disclaimer: Comparing with Older Indicator Versions There are numerous problems with using Southeast Blueprint indicators for change analysis. Please consult Blueprint staff if you would like to do this (email [hilary_morris@fws.gov]). Literature Cited Anderson, M.G. and Barnett, A. 2017. Resilient Coastal Sites for Conservation in the Northeast and Mid-Atlantic US. The Nature Conservancy, Eastern Conservation Science.[[https://easterndivision.s3.amazonaws.com/coastal/Resilient_Coastal_Sites_for_Conservation_NE_Mid_Atlantic.pdf]]. Anderson, M.G. and Barnett, A. 2019. Resilient Coastal Sites for Conservation in the Gulf of Mexico US. The Nature Conservancy, Eastern Conservation Science. [[https://www.conservationgateway.org/ConservationByGeography/NorthAmerica/UnitedStates/edc/Documents/GulfOfMexico_Resilient_Coastal_Sites_31Oct2019.pdf]]. Anderson, M.G. and Barnett, A. 2019. Resilient Coastal Sites for Conservation in the South Atlantic US. The Nature Conservancy, Eastern Conservation Science. [[https://www.conservationgateway.org/ConservationByGeography/NorthAmerica/UnitedStates/edc/Documents/SouthAtlantic_Resilient_Coastal_Sites_31Oct2019.pdf]]. Anderson, M.G., Ferree, C.E., 2010. Conserving the stage: climate change and the geophysical underpinnings of species diversity. PLoS One 5, e11554. [[https://doi.org/10.1371/journal.pone.0011554]]. The Nature Conservancy. Datasets for the Conterminous U.S.: Resilient Sites (Terrestrial and Coastal). Esri File Geodatabase format. Accessed December 3, 2024. [[https://www.conservationgateway.org/ConservationPractices/ClimateChange/Pages/RCN-Downloads.aspx]].