Vegetation Classification and Mapping Project Report - USGS
Vegetation Classification and Mapping Project Report - USGS
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 />
COMMON NAME (PARK-SPECIFIC): TIDAL MESOHALINE AND POLYHALINE<br />
MARSH (LOW SALT MARSH)<br />
SYNONYMS<br />
USNVC English Name: Saltmarsh Cordgrass - Saltgrass Tidal Herbaceous <strong>Vegetation</strong><br />
USNVC Scientific Name: Spartina alterniflora - Distichlis spicata Tidal Herbaceous<br />
<strong>Vegetation</strong><br />
USNVC Identifier: CEGL006586<br />
LOCAL INFORMATION<br />
Environmental Description: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Low Salt Marsh) are salt<br />
marshes characterized by very low species diversity <strong>and</strong> low plant stature. Mesohaline conditions<br />
comprise salt concentrations between 5 <strong>and</strong> 18 ppt, whereas polyhaline conditions range from 18<br />
to 30 ppt. In Colonial National Historical Park, these marshes occur as small riverine marshes<br />
fringing the mainl<strong>and</strong> along the York River <strong>and</strong> in tidal reaches of its tributaries <strong>and</strong> are subject<br />
to regular, diurnal tides.<br />
<strong>Vegetation</strong> Description: These marshes are strongly dominated by short-statured Spartina<br />
alterniflora (smooth cordgrass), generally less than 1 meter in height, often in association with<br />
Distichlis spicata (inl<strong>and</strong> saltgrass) <strong>and</strong> Spartina patens (saltmeadow cordgrass). Other common<br />
associates include Schoenoplectus robustus (sturdy bulrush), Symphyotrichum tenuifolium<br />
(perennial saltmarsh aster), Schoenoplectus americanus (chairmaker's bulrush), <strong>and</strong> Fimbristylis<br />
castanea (marsh fimbry).<br />
Most Abundant Species:<br />
Stratum Lifeform Species<br />
Herb (field) Graminoid Distichlis spicata (inl<strong>and</strong> saltgrass),<br />
Spartina alterniflora (smooth cordgrass)<br />
Characteristic Species: Distichlis spicata (inl<strong>and</strong> saltgrass), Spartina alterniflora (smooth<br />
cordgrass), Spartina patens (saltmeadow cordgrass).<br />
Other Noteworthy Species: Information not available.<br />
Subnational Distribution with Crosswalk Data:<br />
State SRank Rel Conf SName<br />
Reference<br />
VA<br />
SNR . .<br />
[not crosswalked] .<br />
Local Range: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Low Salt Marsh) was noted along the<br />
York River from Ringfield / King Creek to Yorktown Creek. It is one of two associations<br />
included in the map class Tidal Mesohaline <strong>and</strong> Polyhaline Marsh. The two associations cannot<br />
be mapped separately based on photo signatures, <strong>and</strong> a combined map class was used for the<br />
vegetation map.<br />
<strong>Classification</strong> Comments: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Low Salt Marsh) is<br />
distinguished by the dominance of Spartina alterniflora (smooth cordgrass) occurring with<br />
species indicative of mesohaline conditions such as Spartina patens (saltmeadow cordgrass) <strong>and</strong><br />
Distichlis spicata (inl<strong>and</strong> saltgrass).<br />
Other Comments: Near-shore pocket marshes may have a fringe of Oligohaline Marsh<br />
dominated by Typha angustifolia (narrowleaf cattail) <strong>and</strong> Spartina cynosuroides (big cordgrass)<br />
next to shore that is too small to map separately.<br />
Local Description Authors: K. D. Patterson.<br />
Plots: None.<br />
Colonial National Historical Park Inventory Notes: Information not available.<br />
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