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Vegetation Classification and Mapping Project Report - USGS

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<strong>USGS</strong>-NPS <strong>Vegetation</strong> <strong>Mapping</strong> Program<br />

Colonial National Historical Park<br />

Local Range: Tidal Freshwater Marsh is mapped at Jamestown Isl<strong>and</strong> in the vicinity of S<strong>and</strong>y<br />

Bay <strong>and</strong> the upper portions of the Back River, at Papermill Creek, <strong>and</strong> at College Creek /<br />

Kingsmill along Halfway Creek. In total it covers 125 hectares (308 acres) in Colonial National<br />

Historical Park.<br />

<strong>Classification</strong> Comments: Tidal Freshwater Marsh is distinguished from other tidal marsh<br />

vegetation in Colonial National Historical Park by occurring in areas where there is enough<br />

freshwater input to influence the vegetation composition so that the dominant species include<br />

Pelt<strong>and</strong>ra virginica (green arrow arum) <strong>and</strong> Zizania aquatica var. aquatica (annual wildrice) <strong>and</strong><br />

without dominance by Spartina cynosuroides (big cordgrass). Some areas mapped as Freshwater<br />

Tidal Marsh may be transitional to Oligohaline Marsh <strong>and</strong> have species composition<br />

intermediate between the two concepts.<br />

Other Comments: Information not available.<br />

Local Description Authors: K. D. Patterson.<br />

Plots: COLO.111, COLO.119.<br />

Colonial National Historical Park Inventory Notes: Information not available.<br />

GLOBAL INFORMATION<br />

USNVC CLASSIFICATION<br />

Physiognomic Class Herbaceous <strong>Vegetation</strong> (V)<br />

Physiognomic Subclass Perennial forb vegetation (V.B.)<br />

Physiognomic Group Temperate or subpolar perennial forb vegetation (V.B.2.)<br />

Physiognomic Subgroup Natural/Semi-natural temperate or subpolar perennial forb vegetation (V.B.2.N.)<br />

Formation Tidal temperate perennial forb vegetation (V.B.2.N.g.)<br />

Alliance Pelt<strong>and</strong>ra virginica - Pontederia cordata Tidal Herbaceous Alliance (A.1703)<br />

Alliance (English name) Green Arrow-arum - Pickerelweed Tidal Herbaceous Alliance<br />

Association Pelt<strong>and</strong>ra virginica - Pontederia cordata Tidal Herbaceous <strong>Vegetation</strong><br />

Association (English name) Green Arrow-arum - Pickerelweed Tidal Herbaceous <strong>Vegetation</strong><br />

Ecological System(s): Northern Atlantic Coastal Plain Fresh <strong>and</strong> Oligohaline Tidal Marsh<br />

(CES203.516).<br />

Acadian Estuary Marsh (CES201.579).<br />

GLOBAL DESCRIPTION<br />

Concept Summary: This freshwater low tidal marsh is dominated by variable mixtures of<br />

Pelt<strong>and</strong>ra virginica (green arrow arum) <strong>and</strong> Pontederia cordata (pickerelweed) that are best<br />

expressed along the North Atlantic Coast southward to Virginia. It occurs on mucky substrates of<br />

variable depth at low elevations within the freshwater tidal zone, often bordering open water.<br />

Pelt<strong>and</strong>ra virginica (green arrow arum) <strong>and</strong> Pontederia cordata (pickerelweed) are codominant.<br />

Associated species can include Bidens spp. (beggarticks), Zizania aquatica (annual wildrice),<br />

Sagittaria latifolia (broadleaf arrowhead), Acorus americanus (sweetflag), Nuphar lutea ssp.<br />

advena (yellow pond-lily), Polygonum arifolium (halberdleaf tearthumb), Polygonum<br />

hydropiperoides (swamp smartweed), <strong>and</strong> Polygonum sagittatum (arrowleaf tearthumb).<br />

Environmental Description: This community occurs low within freshwater tidal marshes on<br />

muck substrates of variable depth. There is a long duration of tidal flooding, <strong>and</strong> the community<br />

is exposed only for a short period of time each day when the tide is out.<br />

<strong>Vegetation</strong> Description: This community is codominated by leafy forbs Pelt<strong>and</strong>ra virginica<br />

(green arrow arum) <strong>and</strong> Pontederia cordata (pickerelweed). Associated species can include<br />

Zizania aquatica (annual wildrice), Sagittaria latifolia (broadleaf arrowhead), Acorus<br />

americanus (sweetflag), Polygonum arifolium (halberdleaf tearthumb), Polygonum<br />

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