Kate V. Ackerman Brian D. Andrews Neil K. Ganju Zafer Defne 20251211 1.0 vector digital data data release DOI:10.5066/P13E2NM2 Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P13E2NM2 https://www.sciencebase.gov/catalog/item/68ac9e7fd4be0263d2491218 Kate V. Ackerman Brian D. Andrews Neil K. Ganju Zafer Defne 2025 1.0 vector digital data data release DOI:10.5066/P13E2NM2 Reston, VA U.S. Geological Survey Suggested citation: Ackerman, K.V., Andrews, B.D., Ganju, N.K., and Defne, Z., 2025, Geospatial data in support of structured decision making for northeast coastal parks: U.S. Geological Survey data release, https://doi.org/10.5066/P13E2NM2. https://doi.org/10.5066/P13E2NM2 https://www.sciencebase.gov/catalog/item/685eb64cd4be025490e9e690 Salt marshes provide a range of ecosystem services, including storm protection, recreation, and commercial fishery habitat provision. The National Park Service (NPS) aims to preserve and protect salt marshes in order to achieve multiple objectives which address their mission: to preserve unimpaired the natural and cultural resources and values of their publicly held lands. Ongoing threats, including sea-level rise, sediment deficits, invasive species, and anthropogenic pressure have led to substantial salt marsh loss in the northeast US over the last century prompting increased investment in their protection and restoration. Here we describe a structured decision making (SDM) framework involving eight NPS units designed to help guide restoration planning and investment, through identification of priority marshes. The framework was developed first through a facilitated workshop with all units, followed by unit-specific workshops where priorities were adjusted to reflect the natural and cultural resources within the unit. The final product is a series of maps depicting performance metrics over a consistent geospatial framework. Integration of these metrics into decision support tools will help guide marsh restoration investments through identification of marsh units and complexes that maximize agency priorities and objectives. This dataset represents the regional and unit-specific metrics generated for Boston Harbor Islands National Recreation Area (BOHA). This shapefile provides the geospatial metrics generated for Boston Harbor Islands National Recreation Area (BOHA) to be used in the structured decision making (SDM) process. All links for cited references and data portals were valid at the time of the work, but support for these web resources may change over time. 2025 publication date Complete None -71.016965 -70.867619 42.367290 42.256924 USGS Thesaurus geospatial datasets wetland ecosystems wetland functions coastal ecosystems coastal processes sea-level change sediment transport estuarine processes vegetation None U.S. Geological Survey USGS Woods Hole Coastal and Marine Science Center Coastal and Marine Hazards and Resources Program National Park Service NPS structured decision making SDM salt marsh marsh health estuary UVVR Lifespan ISO 19115 Topic Category oceans inlandWaters environment USGS Metadata Identifier USGS:68ac9e7fd4be0263d2491218 None Atlantic Ocean United States Massachusetts Suffolk County Boston Harbor Massachusetts Bay Hingham Bay Quincy Bay Boston Harbor Islands National Recreation Area BOHA No access constraints. Please see 'Distribution Information' for details. Each marsh unit is defined for scientific research purposes and should not be used as a sole source of reference for any regulations and policy making. These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. U.S. Geological Survey Kate V. Ackerman Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 508-548-8700 x2331 508-457-2310 kackerman@usgs.gov https://www.sciencebase.gov/catalog/file/get/68ac9e7fd4be0263d2491218/?name=BOHA_SaltMarsh_Browse.png&allowOpen=true Graphic showing the BOHA salt marshes PNG Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS Pro (version 3.2.1) Z. Defne K.V. Ackerman B.D. Andrews N.K. Ganju 2025 1.0 vector digital data data release DOI:10.5066/P18BWN2U Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P18BWN2U https://www.sciencebase.gov/catalog/item/677d4d5dd34e480c9507fa29 Marsh units, and water and land boundaries, inherit their accuracy from the vertical and horizontal accuracy of the elevation data (source of elevation data is found in Defne and others, 2023), as well as the accuracy of the wetland demarcation provided by the U.S. Fish and Wildlife Service National Wetland Inventory (USFWS NWI). Marsh units were evaluated for geoprocessing topology errors and, if found, errors were fixed and validated. The polygons were checked for correct geometry and do not overlap. A visual comparison between NAIP imagery was performed at randomly selected sites to verify the land and water boundaries. For UVVR, marsh polygons without any vegetation were assigned a value of -1. For lifespan, negative values indicate the estimated lifespan is depleted and loss is imminent and some flagged units (see description for the FLG variable) are assigned a lifespan estimate of -9999. The results are specific to the marsh polygons defined within the boundaries of the Boston Harbor Islands National Recreation Area (BOHA) salt marsh complex. A detailed on-the-ground analysis of a single site may result in a different interpretation of the wetland and marsh unit boundaries. Horizontal accuracy is inherited from the source dataset (Defne and others, 2023) that delineates the marsh units and is considered to be +/- 6 meters (m). Because the elevation values are averaged over delineated polygons, vertical accuracy of marsh unit elevation depends on both the horizontal accuracy of NWI dataset and the vertical accuracy of source elevation data (CoNED). CoNED vertical elevation accuracy was 0.2 m. Z. Defne N.K. Ganju K.V. Ackerman 2023 1.0 vector digital data data release DOI:10.5066/P9FSPWSF Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P9PL08GJ https://www.sciencebase.gov/catalog/item/640617c2d34e69298812cc07 online 2023 publication date mu_lifespan_MA.shp This shapefile is used as a starting point for the SDM metrics shapefile published here (BOHA_SDM_Metrics.shp). The marsh unit unique identification number (FID_CMU), the total area of the marsh unit (ATOT_M2), the area of the vegetated portion of the marsh unit (AVEG_M2), the lifespan under global mean sea-level rise of 0.5m and 1.0m by 2100 (GMSL05, GMSL10), the unvegetated to vegetated marsh ratio (UVVR), and flagged anomalous units (FLG) are all carried from the source shapefile (mu_lifespan_MA.shp) into the BOHA_SDM_Metrics.shp shapefile. Downloaded in April 2024. J.R. Holmquist L. Windham-Myers 2021 raster digital data Oak Ridge, TN ORNL DAAC https://doi.org/10.3334/ORNLDAAC/1844 online 2010 ground condition relative_tidal_elevation.tif Used the relative tidal elevation (elevation normalized to the tidal range), termed Zstar (Z*). Z* = (orthometric elevation (m) - mean sea level (m)) / (mean high water (m) - mean sea level(m)). Downloaded in April 2024. National Oceanic and Atmospheric Administration (NOAA) Office for Coastal Management (OCM) 2019 raster digital data Charleston, SC NOAA's Ocean Service, Office for Coastal Management (OCM) https://coast.noaa.gov/digitalcoast/data/slr-wetland.html online 2016 ground condition marsh_migration.tif Marsh migration inland boundary under sea-level rise. Downloaded the Massachusetts data in January 2024. U.S. Geological Survey 2022 vector digital data Reston, VA U.S. Geological Survey https://www.usgs.gov/core-science-systems/ngp/national-hydrography https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Hydrography/NHDPlusHR/VPU/Current/GDB/ online 2022 publication date NHDPlus Catchment NHD Plus catchment polygons for HUC 0109. Downloaded in January 2025. U.S. Fish and Wildlife Service 2020 vector digital data Washington, D.C. U.S. Fish and Wildlife Service https://www.fws.gov/wetlands/data/Data-Download.html online 2020 publication date NWI.shp Downloaded the wetlands data for Massachusetts in January 2020. E.K. Peck J.E. Walker J.D. Woodruff N.K. Ganju 2024 vector digital data data release DOI:10.5066/P13WF8ZT Reston, VA U.S. Geological Survey https://doi.org/10.5066/P13WF8ZT online 2024 publication date NortheastUSDitches_Polyline.shp Ditches shapefile. Downloaded in March 2024. E.F. Largay L.A. Sneddon 2017 vector digital data Fort Collins, CO National Park Service https://irma.nps.gov/DataStore/Reference/Profile/2245717 digital 2017 publication date BOHA_Veg_Poly Location of Phragmites in BOHA. Downloaded April 2024. Boston Harbor Islands National Recreation Area 2024 vector digital data online 2024 publication date SAV.shp At the time of publication, seagrass (ruppia) data were not publicly available from NPS. Received the data from BOHA, November 2024. Boston Harbor Islands National Recreation Area 2024 vector digital data online 2024 publication date Birds.shp At the time of publication, the location of breeding bird nesting habitats were not publicly available from NPS. Received the data from BOHA, November 2024. National Park Service 2024 vector digital data online 2024 publication date BOHA_Buildings At the time of publication, building locations data were not publicly available from NPS. Received the data from BOHA, November 2024. T.K. Sterne E.A. Pendleton E.E. Lentz R.E. Henderson 2023 1.0 raster digital data data release DOI:10.5066/P96A2Q5X Reston, VA U.S. Geological Survey https://www.sciencebase.gov/catalog/item/6197cb8dd34eb622f692ee19 online 2023 publication date USGS_CCL_MaximumCCL_2022.tif Dataset that estimates the coastal change likelihood across the Northeast. Downloaded in March 2024. K.V. Ackerman Z. Defne N.K. Ganju 2021 1.0 vector digital data data release DOI:10.5066/P97E086F Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://www.sciencebase.gov/catalog/item/60f992fcd34e3ccd82fe3fbf online 2021 publication date CMU_MA.shp Conceptual marsh units that have vegetated and unvegetated polygons delineated. Downloaded in April 2024. V.L. Woltz C. LaFosse Stagg K.B. Byrd L. Windham-Myers A.S. Rovai Z. Zhu 2023 1.0 raster digital data data release DOI:10.5066/P9I1PCLS Reston, VA U.S. Geological Survey https://doi.org/10.5066/P9I1PCLS https://www.sciencebase.gov/catalog/item/6419e5b6d34eb496d1d29ca1 online 2023 publication date BiomassC_CONUSTidalMarshes_gCm2.tif Dataset of the biomass carbon stock in coastal herbaceous wetlands. The first link is to the data release and the second link is to the specific dataset used. Downloaded in March 2024. U.S. Department of Commerce, U.S. Census Bureau, Geography Division, Geospatial Products Branch 2023 Washington, D.C. U.S. Census Bureau https://catalog.data.gov/dataset/tiger-line-shapefile-current-state-massachusetts-2020-census-block https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/USA_Census_Tracts/FeatureServer online 2023 publication date Census_Blocks.shp Census blocks. Downloaded in March 2024. National Park Service 2024 Washington, D.C. National Park Service https://irma.nps.gov/Stats/Reports/Park online 2024 publication date Annual_Visitation Number of visitors to BOHA in 2023. Downloaded in August 2024. National Park Service, Cultural Resource GIS Facility 20220125 vector digital data Washington, DC National Park Service online 2022 publication date Cultural_1.shp This dataset was accessed and used by Dennis Skidds (NPS) to identify marsh units that are within 1 kilometer (km) of National Historic Sites and Cultural Landscapes. National Park Service, Cultural Resource GIS Facility 20220125 vector digital data Washington, DC National Park Service online 2022 publication date Cultural_2.shp This dataset was accessed and used by Dennis Skidds (NPS) to identify marsh units that are within 1 km of National Historic Sites and Cultural Landscapes. National Park Service, Cultural Resource GIS Facility 20220125 vector digital data Washington, DC National Park Service online 2022 publication date Cultural_3.shp This dataset was accessed and used by Dennis Skidds (NPS) to identify marsh units that are within 1 km of National Historic Sites and Cultural Landscapes. National Park Service, Cultural Resource GIS Facility 20220125 vector digital data Washington, DC National Park Service online 2022 publication date Cultural_4.shp This dataset was accessed and used by Dennis Skidds (NPS) to identify marsh units that are within 1 km of National Historic Sites and Cultural Landscapes. National Park Service, Cultural Resource GIS Facility 20220125 vector digital data Washington, DC National Park Service online 2022 publication date Cultural_5.shp This dataset was accessed and used by Dennis Skidds (NPS) to identify marsh units that are within 1 km of National Historic Sites and Cultural Landscapes. National Park Service 2022 vector digital data Washington, DC NPS Natural Resources Inventory and Monitoring Division https://doi.org/10.57830/2287631 online 2022 publication date NPS_boundary.shp Used for delineation of park boundaries. Downloaded data in July 2022. All process steps were performed by either Kate Ackerman or Brian Andrews (contact information in this process step and the next), using ArcGIS Pro (ver.3.2.1). For simple operations the name of the geoprocessing tool used is given in capital letters; for complex operations, the name of the geoprocessing tool used is given in capital letters and any critical parameters used are given in parentheses, separated by a semicolon, immediately after the tool name. The input and output file names are provided in [square brackets] when necessary. Units for length and area calculations are meters (m) and square meters (m2) unless otherwise stated. 2025 Kate Ackerman U.S. Geological Survey Geologist mailing address

384 Woods Hole Road

Woods Hole MA 02543 US 508-548-8700 x2331 508-457-2310 kackerman@usgs.gov Export [mu_lifespan_MA.shp] to create a new shapefile [BOHA_SDM_Metrics.shp], keeping the marsh units that are within the park boundary, and the fields that are needed for the SDM performance metrics: the marsh unit unique identification number (FID_CMU), the total area of the marsh unit (ATOT_M2), the area of the vegetated portion of the marsh unit (AVEG_M2), the lifespan under global mean sea-level rise of 0.5m and 1.0m by 2100 (GMSL05, GMSL10), the unvegetated to vegetated marsh ratio (UVVR), and the flag denoting anomalous marsh units (FLG). Project the shapefile from WGS 1984 Web Mercator Auxiliary Sphere to NAD 1983 (2011) UTM 19N. mu_lifespan_MA.shp 2025 BOHA_SDM_Metrics.shp Brian Andrews U.S. Geological Survey Geographer mailing address

384 Woods Hole Road

Woods Hole MA 02543 US 508-548-8700 x2348 508-457-2310 bandrews@usgs.gov Create attribute "Zstar" to calculate elevation relative to tidal range. Calculate the mean relative wetland elevation value relative to tidal range (Zstar (Z*)) within each marsh unit (FID_CMU). Zstar, the relative tidal elevation value, is a metric that normalizes elevation to the tidal amplitude at mean high water. Z* = (orthometric elevation - mean sea level) / (mean high water - mean sea level). Run ZONAL STATISTICS AS TABLE (feature zone data: [BOHA_SDM_Metrics.shp], zone field: FID_CMU, value raster: [relative_tidal_elevation.tif], statistics type= Mean) to calculate the average Z* value for each marsh unit. In [BOHA_SDM_Metrics.shp], add new attribute "Zstar" (Double) to attribute table and populate with results of zonal statistics (MEAN) by joining via the "FID_CMU" field. Assign a value of -9999 for marsh units that do not have Zstar data. BOHA_SDM_Metrics.shp relative_tidal_elevation.tif 2025 BOHA_SDM_Metrics.shp Create attribute “AMIG_M2” to assess the marsh migration potential of each marsh unit, calculated in terms of available migration area, under 2 feet of local sea-level rise, for each marsh unit. This process step followed the methodology detailed in "Chesapeake Bay marsh migration potential under sea-level rise" (Defne and others, 2025), and used these input datasets for BOHA: (1) Marsh migration datasets for Massachusetts [marsh_migration.tif] (2) NHD datasets for HUC 0109 [NHDPlus Catchment]. The migration space is based on the NOAA marsh migration predictions under 2 feet of local sea-level rise and divided into smaller parcels by using the National Hydrography Dataset Plus (NHD Plus) catchments. The marsh migration space is then distributed to the marsh units. BOHA_SDM_Metrics.shp marsh_migration.tif NHDPlus Catchment 2025 BOHA_SDM_Metrics.shp Create attribute “NWIclass” to calculate the number of different coastal wetland (NWI subclasses) types found within a marsh unit. (1) Create a shapefile of the NWI classes that are used for the marsh unit analysis. From [NWI.shp] SELECT (ATTRIBUTE LIKE 'E2%EM%' OR ATTRIBUTE LIKE 'E2AB3%' OR ATTRIBUTE LIKE 'E2EM%' OR ATTRIBUTE LIKE 'E2SS%' OR ATTRIBUTE LIKE 'E2US4%'), EXPORT features to create [NWI_exclusive_select.shp]. Add an additional field that captures the first 5 digits of the NWI attribute field (no modifiers are retained). (2) PAIRWISE INTERSECT the NWI [NWI_exclusive_select.shp] and the marsh units [BOHA_SDM_Metrics.shp] to assign NWI classes to each marsh unit. DISSOLVE the resulting shapefile (Dissolve field: FID_CMU, Concatenate) to obtain a list of all NWI classes found in each marsh unit. Calculate the number of different NWI subclasses found in each marsh unit. BOHA_SDM_Metrics.shp NWI.shp 2025 BOHA_SDM_Metrics.shp Create attribute "Ditchkmkm2" to calculate the density of ditches for each marsh unit. It is calculated by summing the linear length of ditches (km) divided by the area of each marsh unit (square kilometers). The final value for each marsh unit is ditching intensity (linear kilometers of ditch per square kilometer of marsh unit area). PAIRWISE INTERSECT the ditches [NortheastUSDitches_Polyline.shp] and marsh units [BOHA_SDM_Metrics.shp] then SUMMARIZE ATTRIBUTES by FID_CMU to get total length of ditches in each marsh unit. Calculate the ditch density (km/km2): total length of ditches (km) in a marsh, divided by the total marsh unit area (km2). BOHA_SDM_Metrics.shp NortheastUSDitches_Polyline.shp 2025 BOHA_SDM_Metrics.shp Create attribute "Phrag" that indicates the presence or absence of Phragmites in the marsh unit. SELECT BY LOCATION (intersect) [BOHA_Veg_Poly] and [BOHA_SDM_Metrics.shp] to identify marsh units that have Phragmites. If a marsh unit has Phragmites, assign a value of 1 to the marsh unit for the “Phrag” attribute. BOHA_SDM_Metrics.shp BOHA_Veg_Poly 2024 BOHA_SDM_Metrics.shp Create attribute "BioDiv" that provides information on the biodiversity of the marsh unit, which is the summation of the "Bird" (whether the marsh unit intersects a breeding bird nesting habitat) and the "SAV" (whether the marsh unit is within 100m of seagrass beds) attributes. Bird: SELECT BY LOCATION (intersect) [Birds.shp] and [BOHA_SDM_Metrics.shp] to identify marsh units that intersect breeding bird nesting habitat. If they do, the marsh unit is assigned a value of 1 for the “Bird” attribute. SAV: SELECT BY LOCATION (intersect, 100 m) [SAV.shp] and [BOHA_SDM_Metrics.shp] to identify marsh units that have seagrass within 100 m of the marsh unit. If seagrass beds are within 100 m of the marsh unit, the marsh unit is assigned a value of 1 for the “SAV” attribute. BioDiv: The “BioDiv” attribute is the sum of the “Bird” and “SAV” attributes. BOHA_SDM_Metrics.shp Birds.shp SAV.shp 2025 BOHA_SDM_Metrics.shp Create attribute “Quantl” to compare the size of marsh units across the Park. Based on the total marsh unit area, the marsh units are binned into 5 equal area bins. Each marsh unit is placed into a bin based on its size (bin 1 contains the smallest marsh units; bin 5 contains the largest marsh units). Calculate the total area of all marsh units, sort marsh units by size, divide the dataset into five approximately equal parts based on area. The smallest marsh units will have a Quantl value of 1, the largest marsh units will have a Quantl value of 5. BOHA_SDM_Metrics.shp 2025 BOHA_SDM_Metrics.shp Create attribute "AssetScore" to estimate the protection a marsh unit provides to an asset (building). The Asset Score is calculated by dividing the maximum Coastal Change Likelihood (USGS_CCL_MaximumCCL_2022.tif) score within 100 m of an asset by the distance in meters (binned) from the asset to the marsh unit. The Asset Score ranges from 0 (minimal protection provided by marsh unit) to 10 (maximal protection). Note that for BOHA, there are no buildings within 1.5 km of marsh units, therefore all marsh units have an asset score of 0. The process steps are included here for completeness. 1)PROJECT source shapefiles from WGS 1984 Web Mercator coordinate system to NAD 83 (2011) UTM 19N and output as feature classes within a geodatabase to ensure distance calculations are accurate. Source files: marsh units: [BOHA_SDM_Metrics]; buildings: [BOHA_Buildings]; output: [BOHA_BuildingFeatures_UTM19]. 2)Calculate the maximum CCL value within 100 m of each of the assets (buildings) within BOHA boundary. BUFFER [BOHA_BuildingFeatures_UTM19] by 100 m, output= [BOHA_BID100mBuff]. ZONAL STATISTICS AS TABLE (Input: [BOHA_BID100mBuff]; zone field=BID; Input Value Raster: [USGS_CCL_2022.tif]; Output table: [BOHA_BuildingMaxCCL_100m]; Statistics Type=Maximum). 3)Calculate the distance in meters from the buildings [BOHABuildingFeatures_UTM19] to the closest point along the boundary of all marsh units [BOHA_SDM_Metrics] that are within 1 km of each feature in [BOHABuildingFeatures_UTM19]. GENERATE NEAR TABLE (Output table: [BOHA_BuildingsNearMU_1km]). Only need to retain the fields "IN_FID", "NEAR_FID", and "NEAR_DIST" from the output table. Note that for BOHA, there are no buildings within 1 km of marsh units. 4)Join (JOIN FIELD) the MAX CCL value from table [BOHA_BuildingMaxCCL_100m] (join field=BID) to the output table [BOHA_BuildingsNearMU_1km] (join field=IN_FID; Transfer Fields=MAX). 5)ADD FIELDS (multiple) (Input Table: [BOHA_SDM_Metrics]; Field Names: "Dist" (Short) and "AssetScore" (Double)). 6)ADD JOIN (Join one to many) (Input Table: [BOHA_SDM_Metrics]; input field=OBJECTID; Join Table: [BOHA_BuildingsNearMU_1km]; Join Field: NEAR_FID; transfer all fields). EXPORT joined feature class to [BOHA_SDM_Metrics_AS]. 7) Calculate the "AssetScore" field in 2 steps. In [BOHA_SDM_Metrics_AS], first CALCULATE FIELD "Dist" by rounding up the "NEAR_DIST" value (Data type=double from step 3 and 6) in meters to the nearest 100, then dividing the rounded number by 100. For example, a "NEAR_DIST" value of 23.55 m rounds to 100, then divided by 100 gives a “Dist” value of 1; a "NEAR_DIST" of 176.16 m gives "Dist" value of 2. Second, CALCULATE FIELD "AssetScore" by dividing "MAX" (max CCL) by "DIST." 8)Run PAIRWISE DISSOLVE (input file: [BOHA_SDM_Metrics_AS]; Dissolve field: FID_CMU; Statistics field: AssetScore; Statistics Type: Maximum; Output: [BOHA_SDM_Metrics_AS_Dissolve]) to dissolve duplicate "FID CMU" records from the one-to-many join in step 6. This final step retains the maximum "AssetScore" for any one-to-many relationships between each marsh unit and building pair(s). The output dissolved feature class does not retain all the fields from the source [BOHA_SDM_Metrics_AS] and only retains "FID_CMU" and "MAX_AssetScore." 9)JOIN FIELD "MAX_AssetScore" from [BOHA_SDM_Metrics_AS] back into original source [BOHA_SDM_Metrics.shp] using the "FID_CMU" field. BOHA_SDM_Metrics.shp BOHA_Buildings USGS_CCL_MaximumCCL_2022.tif 2025 BOHA_SDM_Metrics.shp Create attribute “VegMU_MgC” to summarize the amount of biomass carbon in the vegetated part of the marsh unit. Extract the vegetated portion of the marsh unit polygons. SELECT BY ATTRIBUTES from [CMU_MA.shp] that are within and adjacent to the park boundary [NPS_boundary.shp] where "TYP"= 'vegetated'; output: [CMU_BOHA_VEG.shp]. PROJECT [CMU_BOHA_VEG.shp] to Albers_Conical_Equal_Area to match the projection of the biomass carbon file. Run ZONAL STATISTICS AS TABLE (feature zone data: [CMU_BOHA_VEG.shp], zone field: FID_CMU, value raster: [BiomassC_CONUSTidalMarshes_gCm2.tif], Statistics type=Mean) to get the average biomass carbon for the vegetated portion of the marsh unit. JOIN the MEAN value to [CMU_BOHA_VEG.shp]. Multiply MEAN by the vegetated area of the marsh unit to get total grams of carbon in the vegetated portion of the marsh unit. Report the value in megagrams of carbon (MgC). Assign a value of -9999 for marsh units that do not have carbon data. BOHA_SDM_Metrics.shp CMU_MA.shp NPS_boundary.shp BiomassC_CONUSTidalMarshes_gCm2.tif 2025 BOHA_SDM_Metrics.shp Create new attribute “Pop” to calculate the total population within 50 miles of the marsh units. The population value is the same for all marsh units. SELECT BY LOCATION (intersect, 50 miles) [Census_Blocks.shp] and [BOHA_SDM_Metrics.shp]. Calculate total population in the selected census blocks. BOHA_SDM_Metrics.shp Census_Blocks.shp 2025 BOHA_SDM_Metrics.shp Create new attribute “Visit” that is the total number of visitors to the park in 2023. This value is the same for all marsh units. The number of visitors to BOHA in 2023 was obtained from [Annual_Visitation]. BOHA_SDM_Metrics.shp Annual_Visitation 2025 BOHA_SDM_Metrics.shp Create 3 attributes “NHS,” “CL,” and “NHS_CL” to identify marshes that are close to cultural and historical resources. "NHS" identifies marsh units that are within 1 km of a historic site (National Historic Site (NHS), National Register of Historic Places (NRHP)), "CL" identifies marsh units that are within 1 km of a Cultural Landscape (CL). The attribute "NHS_CL" indicates marsh unit that are within 1 km of either an NHS or CL site or both (value of 1 or 2, respectively). Dennis Skidds (NPS) aggregated the park-restricted data to determine whether a marsh unit is within 1 km of the cultural and historical resources. BOHA_SDM_Metrics.shp Cultural_1.shp Cultural_2.shp Cultural_3.shp Cultural_4.shp Cultural_5.shp 2024 BOHA_SDM_Metrics.shp Dennis Skidds National Park Service Regional GIS Program Manager mailing and physical address

1 Greenhouse Rd

Kingston RI 02881 US 401-374-4994 dennis_skidds@nps.gov Create an attribute "InOutPark" to denote whether a marsh unit is inside or outside of the park boundary. SELECT BY LOCATION (intersect) [NPS_boundary.shp] and [BOHA_SDM_Metrics.shp] to identify whether the marsh unit is inside or outside of the park boundary. BOHA_SDM_Metrics.shp NPS_boundary.shp 2025 BOHA_SDM_Metrics.shp PROJECT (Output coordinate system=WGS 1984 Web Mercator Auxiliary Sphere) [BOHA_SDM_Metrics.shp] to Web Mercator. BOHA_SDM_Metrics.shp 2025 BOHA_SDM_Metrics.shp Vector G-polygon 27 WGS 1984 Web Mercator Auxiliary Sphere (ESRI Full Name: WGS_1984_Web_Mercator_Auxiliary_Sphere) 0.0 0.0 0.0 0.0 coordinate pair 0.6096 0.6096 Meter D_WGS_1984 WGS_1984 6378137.0 298.25722 BOHA_SDM_Metrics.shp Attribute information associated with marsh units of BOHA salt marsh complex. U.S. Geological Survey FID Internal feature number Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry Esri Coordinates defining the feature type. FID_CMU Sequential unique whole number that represents the identification number for each conceptual marsh unit. This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS 1838 3635 none ATOT_M2 Total surface area of a marsh unit in square meters. This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS 998.002 33699.691 square meters AVEG_M2 Surface area of vegetated part of a marsh unit in square meters. This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS 771.639 27209.826 square meters GMSL05 Lifespan for a marsh unit (in years) for global mean sea-level rise of 0.5 m by 2100. Negative lifespan values (other than No Data) indicates the estimated lifespan is depleted and loss is imminent. A value of 10,000 indicates a lifespan equal to or greater than 10,000. A value of -9999 indicates no data. This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS 10 10000 years GMSL10 Lifespan for a marsh unit (in years) for global mean sea-level rise of 1.0 m by 2100. Negative lifespan values (other than No Data) indicates the estimated lifespan is depleted and loss is imminent. A value of 10,000 indicates a lifespan equal to or greater than 10,000. A value of -9999 indicates no data. This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS 7 10000 years UVVR Ratio of unvegetated surface area to vegetated surface area. Ordinarily, UVVR ranges from zero (completely vegetated) to infinity (completely unvegetated). However, it is assigned the value of -1 when completely unvegetated. Note that there can be very large values of UVVR (indicating that the marsh unit is mostly unvegetated). This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS 0 9.361 none Zstar Mean wetland elevation above mean sea level relative to the tidal range of the marsh unit. A value of -9999 indicates no data. USGS -0.092 1.44 unitless AMIG_M2 Potential marsh migration area in square meters. USGS 0 49459.837 square meters NWIclass Number of NWI subclasses in a marsh unit. USGS 1 1 None Ditchkmkm2 Ditching intensity (linear kilometers of ditch per square kilometer of marsh unit area). USGS 0 3.301 kilometers per square kilometer Phrag Presence (1) or absence (0) of Phragmites in a marsh unit. USGS 1 Presence of Phragmites in marsh unit. USGS 0 Absence of Phragmites in marsh unit. USGS Bird Marsh units that intersect breeding bird nesting habitat have a value of 1, otherwise they have a value of 0. USGS 1 Marsh unit intersects breeding bird nesting habitat. USGS 0 Marsh unit does not intersect breeding bird nesting habitat. USGS SAV Presence (1) or absence (0) of submerged aquatic vegetation (SAV) within 100m of a marsh unit. USGS 1 Presence of SAV within 100m of a marsh unit. USGS 0 Absence of SAV within 100m of a marsh unit. USGS BioDiv The sum of attributes Bird and SAV to indicate whether a marsh unit has breeding bird nesting habitat within the marsh unit, or SAV adjacent to the marsh unit. If both breeding bird nesting habitat and SAV are present, the value is 2; if only one is present, the value is 1; if neither are present, the value is 0. USGS 2 Presence of breeding bird nesting habitat within the marsh unit, and SAV adjacent to the marsh unit. USGS 1 Presence of breeding bird nesting habitat within the marsh unit, or SAV adjacent to the marsh unit. USGS 0 Absence of breeding bird nesting habitat within the marsh unit, nor SAV adjacent to the marsh unit. USGS Quantl The quantile bin that a marsh unit is assigned to based on its area. The marsh units with the smallest areas are in quantile 1, and the largest marsh units are in quantile 5. USGS 1 5 None AssetScore An estimate of the protection a marsh unit provides to an asset (building). The asset score ranges from 0 (minimal protection provided by marsh unit) to 10 (maximal protection). For BOHA, there are no buildings within 1.5 km of marsh units, therefore all marsh units have an asset score of 0. USGS 0 0 None VegMU_MgC Total biomass carbon in the vegetated portion of the marsh unit. A value of -9999 indicates no data. USGS 0.773 24.210 megagrams carbon Pop The total population within 50 miles of the park boundary. This value is the same for all marsh units. USGS 7,598,039 Total population within 50 miles of the park boundary. USGS Visit The total number of visitors to BOHA in 2023. This value is the same for all marsh units. USGS 27,986 Total number of visitors to BOHA in 2023. USGS NHS Marsh units that are within 1 km of a National Historic Site (NHS, NRHP) have a value of 1, otherwise they have a value of 0. USGS 1 Marsh unit is within 1 km of a National Historic Site. USGS 0 Marsh unit is not within 1 km of a National Historic Site. USGS CL Marsh units that are within 1 km of a Cultural Landscape have a value of 1, otherwise they have a value of 0. USGS 1 Marsh unit is within 1 km of a Cultural Landscape. USGS 0 Marsh unit is not within 1 km of a Cultural Landscape. USGS NHS_CL Marsh unit that are within 1 km of either an NHS or CL site or both have a value of 1 or 2, respectively, otherwise they have a value of 0. USGS 2 Marsh unit is within 1 km of a NHS and a CL site. USGS 1 Marsh unit is within 1 km of a NHS or a CL site. USGS 0 Marsh unit is not within 1 km of a NHS nor a CL site. USGS FLG Marsh unit flag indicating anomalous marsh units based on absence of vegetation, elevation, surface area and tidal range extrapolation. FLG values indicate: (-1) no vegetated area in the marsh unit; (-10) marsh unit elevation higher than the 99.8 percentile; (-100) marsh unit elevation less than the 0.2 percentile; (-200) greater than 25 percent of the marsh unit elevation is hydro-flattened; (-1000) marsh unit surface area less than 900 m2; (-10000) mean tidal range of marsh unit is extrapolated; and (0) no flag. Combination of negative values indicates a combination of flags. For example, -1001 indicates no vegetated area and area less than 900 m2.This attribute was carried over from the original source, mu_lifespan_MA.shp. USGS -10000 0 None InOutPark Classification of marsh unit as either inside or outside of the park boundary. USGS in Marsh unit that is inside the park boundary. USGS out Marsh unit that is outside the park boundary. USGS In this dataset, metrics are calculated for marsh units of Boston Harbor Islands National Recreation Area (BOHA) to be used in an SDM framework to prioritize management actions. All attributes, as well as attribute definitions, are included even if they are not present in any of the marsh units in the park. This is to ensure consistency across parks and recognition that the attribute is not present rather than unaccounted for. USGS U.S. Geological Survey - ScienceBase mailing and physical address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov BOHA_SDM_Metrics.zip (ZIP file contains the shapefile BOHA_SDM_Metrics.shp and the additional shapefile components and FGDC CSDGM metadata in xml format), and browse graphic (BOHA_SaltMarsh_Browse.png) Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Shapefile Esri ArcGIS Pro 3.2.1 This zipped file contains a polygon shapefile and its components, and metadata in xml format. 0.1 https://www.sciencebase.gov/catalog/file/get/68ac9e7fd4be0263d2491218 https://www.sciencebase.gov/catalog/item/68ac9e7fd4be0263d2491218 The first link in network resources is to download data directly. The second link points to a landing page with metadata and data. WMS https://www.sciencebase.gov/catalogMaps/mapping/ows/68ac9e7fd4be0263d2491218?service=wms&request=getcapabilities&version=1.3.0 The link in network resources points to the Web Mapping Services (WMS) end point. WFS https://www.sciencebase.gov/catalogMaps/mapping/ows/68ac9e7fd4be0263d2491218?service=wfs&request=getcapabilities&version=1.0.0 The link in network resources points to the Web Feature Service (WFS) end point. None. No fees are applicable for obtaining the data set. 20251211 U.S. Geological Survey Kate Ackerman Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 508-548-8700 x2331 508-457-2310 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998