Marsh Zone Map

This raster layer describes salt marsh communities in the Northeast Atlantic coast of the United States, from northern Maine to Virginia in 3 X 3 m pixels.  It is freely available for non-commercial use by the public.

Suggested citation: SHARP 2017. “Marsh Habitat Zonation Map”. Saltmarsh Habitat and Avian Research Program. Ver: 26 Oct 2017.

General Layer Description:

Cover/community types categorized in this layer are as follows:

  1. High marsh: Area flooded by average or larger than average amplitude tide (resulting in weekly to monthly flooding) and is dominated by Spartina patensDistichlis spicataJuncus gerardii and short form Spartina alterniflora. In addition, Juncus roemerianusScirpus pungensScirpus robustusLimonium nashiiAster tenuifolius, and Triglochin maritimum are secondary cover.
  2. Low marsh: Area flooded regularly by daily tides and dominated by tall form Spartina alterniflora.
  3. Salt pools/pannes: Depressed, bare areas with sparse vegetation cover and extreme high soil salinities. Generally, pools retain water between high tides while pannes do not.
  4. Terrestrial border: Area infrequently flooded by storm and spring tides and can include areas of marsh with fresh/brackish water due to a high water table and/or runoff from impervious surfaces. Typical plant species include Typha angustifoliaIva frutescensBaccharis halimifoliaSolidago sempervirensPanicum virgatumScirpus robustus, and Spartina pectinata.
  5. Phragmites australis: An exotic species mainly invading disturbed marshes that (sometimes temporarily) cause a shift to a fresh water state (Dreyer & Niering, 1995).
  6. Mudflat: Exposed muddy areas free of vegetation.
  7. Open water: Free-flowing water included within 500m analysis buffer
  8. Upland: Non-marsh cover included within 500m analysis buffer

Folders for each zone include three file types:

  1. ZoneX_DEM (TIFF): High-accuracy classification of tidal marsh communities.
  2. ZoneX_noDEM (TIFF): When no DEM was available, we provide a classification with lower accuracy, produced without DEM data. This layer does not include a terrestrial border or upland class.
  3. ZoneX_dif (.shp): Vector file for each zone indicating where DEM was and was not used for classification within each zone.