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. https://www.tidalmarshbirds.org.
- Marsh Zonation Maps by Ecological Zone (zipped file – see description below)
Zones 1-3 (Maine to Long Island Sound) – MarshLayer (zones 1-3) (464 downloads)
Zones 4-6 (S. Shore of Long Island to Upper DE Bay) – MarshLayer (zones 4-6) (326 downloads)
Zone 7 (Eastern Delmarva Peninsula) – MarshLayer (zone 7) (272 downloads)
Zone 8 (Eastern Shore of Chesapeake Bay) – MarshLayer (zone 8)
- Marsh Zonation Map MetaData – MarshLayer_metadata (278 downloads)
- Marsh Zonation Methods & Description – MarshLayer_whitepaper (297 downloads)
General Layer Description:
Cover/community types categorized in this layer are as follows:
- High marsh: Area flooded by average or larger than average amplitude tide (resulting in weekly to monthly flooding) and is dominated by Spartina patens, Distichlis spicata, Juncus gerardii and short form Spartina alterniflora. In addition, Juncus roemerianus, Scirpus pungens, Scirpus robustus, Limonium nashii, Aster tenuifolius, and Triglochin maritimum are secondary cover.
- Low marsh: Area flooded regularly by daily tides and dominated by tall form Spartina alterniflora.
- 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.
- 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 angustifolia, Iva frutescens, Baccharis halimifolia, Solidago sempervirens, Panicum virgatum, Scirpus robustus, and Spartina pectinata.
- Phragmites australis: An exotic species mainly invading disturbed marshes that (sometimes temporarily) cause a shift to a fresh water state (Dreyer & Niering, 1995).
- Mudflat: Exposed muddy areas free of vegetation.
- Open water: Free-flowing water included within 500m analysis buffer
- Upland: Non-marsh cover included within 500m analysis buffer
Folders for each zone include three file types:
- ZoneX_DEM (TIFF): High-accuracy classification of tidal marsh communities.
- 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.
- ZoneX_dif (.shp): Vector file for each zone indicating where DEM was and was not used for classification within each zone.
The methods for developing this layer as well as suggestions for appropriate uses are detailed in:
Correll, MD, W Hantson, TP Hodgman, BB Cline, CS Elphick, WG Shriver, EL Tymkiw, and BJ Olsen. 2019. Fine-scale mapping of coastal plant communities in the northeastern USA. Wetlands 39(1): 17-28.