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 (TRANSITIONAL MARSH)<br />
SYNONYMS<br />
USNVC English Name: Saltmarsh Cordgrass - Dotted Smartweed - Water-hemp<br />
Herbaceous <strong>Vegetation</strong><br />
USNVC Scientific Name: Spartina alterniflora - Polygonum punctatum - Amaranthus<br />
cannabinus Herbaceous <strong>Vegetation</strong><br />
USNVC Identifier: CEGL006418<br />
LOCAL INFORMATION<br />
Environmental Description: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Transitional Marsh)<br />
occurs in mesohaline to oligohaline waters on the mid-tidal position of large tidal rivers <strong>and</strong> tidal<br />
guts. It receives freshwater input from alluvial sources inl<strong>and</strong> <strong>and</strong> may also receive seepage from<br />
adjacent upl<strong>and</strong>s. These marshes grow on silty mud <strong>and</strong> are subject to regular tidal flooding.<br />
<strong>Vegetation</strong> Description: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Transitional Marsh) is<br />
dominated by dense, saltmarsh grasses with local areas dominated by aquatic forbs. Spartina<br />
alterniflora (smooth cordgrass) is the dominant grass, occurring with Spartina cynosuroides (big<br />
cordgrass) <strong>and</strong> Pelt<strong>and</strong>ra virginica (green arrow arum), which may dominate in patches. This<br />
marsh vegetation may occur as linear b<strong>and</strong>s along tidal channels or as large patches.<br />
Most Abundant Species:<br />
Stratum Lifeform Species<br />
Herb (field)<br />
Graminoid Spartina alterniflora (smooth cordgrass)<br />
Characteristic Species: Pelt<strong>and</strong>ra virginica (green arrow arum), Spartina alterniflora (smooth<br />
cordgrass), Spartina cynosuroides (big cordgrass).<br />
Other Noteworthy Species: Information not available.<br />
Subnational Distribution with Crosswalk Data: Information not available.<br />
Local Range: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Transitional Marsh) is found in the<br />
vicinity of College Creek / Kingsmill. It is one of two associations included in the map class<br />
Tidal Mesohaline <strong>and</strong> Polyhaline Marsh. The two associations cannot be mapped separately<br />
based on photo signatures, <strong>and</strong> a combined map class was used for the vegetation map.<br />
<strong>Classification</strong> Comments: Tidal Mesohaline <strong>and</strong> Polyhaline Marsh (Transitional Marsh) is<br />
distinguished by the dominance of Spartina alterniflora (smooth cordgrass) occurring with<br />
species indicative of more oligohaline or freshwater conditions such as Spartina cynosuroides<br />
(big cordgrass), Pelt<strong>and</strong>ra virginica (green arrow arum), <strong>and</strong> Zizania aquatica var. aquatica<br />
(annual wildrice).<br />
Other Comments: Information not available.<br />
Local Description Authors: K. D. Patterson.<br />
Plots: None.<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 graminoid vegetation (V.A.)<br />
Physiognomic Group Temperate or subpolar grassl<strong>and</strong> (V.A.5.)<br />
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