Three types of data (one with an elevation model (DEM), one without a DEM, and one indicating the difference) are provided for the entire Northeast region and by analysis zone (n=8).
Tidal Marsh Vegetation Classification, DEM, 3m, Northeast U.S. – contains a regional classification produced using a combination of Digital Elevation Model (DEM) and National Agriculture Imagery Program (NAIP) multispectral imagery. All eight cover types are included in this classification. This dataset combined with “Tidal Marsh Vegetation Classification, DEM, 3m, Northeast U.S” provides a contiguous classification of tidal marsh cover types from coastal Maine to Virginia. The eight cover types include:
- High marsh: Area flooded during spring tides related to the lunar cycle and dominated by Spartina patens, Distichlis spicata, Juncus gerardii, and short form Spartina alterniflora. Other species include Juncus roemerianus, Scirpus pungens, Scirpus robustus, Limonium nashii, Aster tenuifolius, and Triglochin maritima.
- 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 extremely 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, Scirpus robustus, and Spartina pectinata.
- Phragmites australis: A species of considerable management interest due to the invasive nature of an introduced form, especially in marshes with freshwater input, upland development, and/or increased nutrients.
- Mudflat: Exposed muddy areas free of vegetation.
- Open water (bordering cover type): Channels and bays leading to open ocean.
- Upland (bordering cover type): All non-marsh terrestrial cover.
Tidal Marsh Vegetation Classification, no DEM, 3m, Northeast U.S. - contains a regional classification produced using NAIP multispectral imagery for areas where no DEM was available to complete the full classification. This layer does not include a terrestrial border or upland class, has overall lower accuracy, and should be used with caution. This layer combined with “Tidal Marsh Vegetation Classification, DEM, 3m, Northeast U.S.” provides a contiguous classification of tidal marsh cover types from coastal Maine to Virginia.
DEM Difference in Tidal Marsh Vegetation Classification, 3m, Northeast U.S. - represents a combined file indicating where DEM was and was not used in the regional classification.
For more information about the development of this layer please contact Mo Correll at Maureen.correll@maine.edu. This set of spatial layers is a product of the Saltmarsh Habitat and Avian Research Program (www.tidalmarshbirds.org).
