This layer depicts the subregions used to run Zonation in Base Blueprint 2022. We break down the Base Blueprint geography into subregions to reduce processing time and help with balancing weights across indicators in such a large and varied region.
Input Data
Mapping Steps
For more details on the mapping steps, code used to create this layer is available in the Southeast Blueprint 2022 Data Download under BlueprintInputs > BaseBlueprint2022 > 6_Code. Generally, we used the following mapping steps:
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Identify the non-coastal state boundaries of subregions using the state boundaries from the EPA Level IV ecoregions.
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Define the coastal edges of the subregions using the coastal extent of the HUC4 watersheds.
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Do some initial grouping of the EPA ecoregions to make larger ecoregions. Usually, we grouped by Level III ecoregions; sometimes we went down to the Level IV ecoregions to make smoother, larger ecoregions.
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The EPA ecoregions include some “islands” where part of an ecoregion is not contiguous with the rest. Because we need contiguous subregions to use in running Zonation, identify those “islands” and assign them to the contiguous ecoregion that surrounds them. In addition, some ecoregions have long, finger-like, “peninsulas” that protrude from the ecoregion. Sometimes we assigned these to the surrounding ecoregion to make smoother edges.
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Union together the modified EPA ecoregions and HUC4 watershed layers and use a reclass function to assign subregions to unique combinations of EPA ecoregions and HUC4 watersheds.
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For the “islands” and “peninsulas” mentioned above, we made exceptions to the above rules and assigned those polygons to the subregion that surrounds them.
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Use the Census TIGER/Lines state boundaries to remove HUC4 areas that extend beyond the Base Blueprint extent. This removes some coastal water areas in the Northeast United States that were outside the Base Blueprint area.
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Use the Marine Ecoregions to define the marine subregions. Clip that area to the South Atlantic Blueprint 2021 extent because we currently do not have marine indicators that extend beyond that area.
Subregion Descriptions
Detailed descriptions of how each subregion is defined are available in the Defining Subregions section of the Southeast Blueprint 2022 Development Process.
Literature Cited
Commission for Environmental Cooperation. 2009. Marine Ecoregions of North America, 2008. Vector digital data. Montréal, Québec, Canada. [https://www.cec.org/north-american-environmental-atlas/marine-ecoregions-level-iii/].
Moilanen, A., L. Meller, J. Leppänen, F.M. Pouzols, H. Kujala, A. Arponen. 2014. Zonation Spatial Conservation Planning Framework and Software V4.0, User Manual. [https://github.com/cbig/zonation-core/releases/download/4.0.0/zonation_manual_v4_0.pdf].
Southeast Conservation Adaptation Strategy (SECAS). 2021. South Atlantic Extent and Subregions 2021. [https://www.sciencebase.gov/catalog/item/61002b01d34ef8d7055c7db2].
U.S. Department of Commerce, U.S. Census Bureau, Geography Division, Spatial Data Collection and Products Branch. TIGER/Line Shapefile, 2021, U.S. Current State and Equivalent National. 2021. [https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html].
U.S. Environmental Protection Agency. Level IV Ecoregions of the Conterminous United States. U.S. EPA Office of Research & Development (ORD) - National Health and Environmental Effects Research Laboratory (NHEERL). Corvallis, OR. Published April 16, 2013. [https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-continental-united-states].
U.S. Geological Survey (USGS). National Watershed Boundary Dataset in FileGDB 10.1 format. Published July 28, 2020. [https://www.usgs.gov/national-hydrography/watershed-boundary-dataset].
