Species Spotlight - Spartina alterniflora

Saltmarsh cordgrass growing in marsh
USDA-NRCS PLANTS Database

Saltmarsh cordgrass, Atlantic cordgrass, Smooth cordgrass
Spartina alterniflora

Description: Spartina alterniflora is a rhizomatous perennial grass that grows up to four feet tall. The stems are hollow and hairless. The leaf blades are 1/4 to 3/5 inches wide. The leaves lack auricles and have ligules that consist of a fringe of hairs. The flowers are inconspicuous and are borne in greatly congested spikes, two to three inches long (Hitchcock et al. 1969).

Habitat: Spartina alterniflora is a plant of the intertidal zone, where it colonizes mudflats or sandflats in saline or brackish water.

Distribution: Native habitat from Quebec and Newfoundland to Florida and Texas. Also planted in many other parts of the world for estuary reclamation. This species is considered a non-native invasive plant on the U.S. Pacific coast.

Status: In its native habitat, this species is highly productive in its ability to export detritus to estuarine systems and is highly regarded for erosion control. Because of their ability to trap sediment, Spartina species have been planted in many parts of the world for estuary reclamation. Though Spartina alterniflora is valued in its native habitat its ability to trap sediment is a cause for concern in Washington, Oregon, and California.

Resources: Hitchcock, C.L., A.Cronquist, M. Ownbey, and J.W. Thompson. 1969. Vascular Plants of the Pacific Northwest. Part 1: Vascular Cryptogams, Gymnosperms, and Monocotyledons. University of Washington Press, Seattle.

The Western Aquatic Plant Management Society

Coastal Change Analysis

Coastal Change Analysis

Estuarine and palustrine (freshwater) wetlands are important coastal habitats, functioning as nursery/nesting and foraging areas for wildlife, including commercially and recreationally important species off in fish, shellfish, and waterbirds. Wetlands also contribute other important ecosystem services such as filtration of waterborne contaminants, stabilization of sediments and shoreline, and protection from flood waters.

In many areas along the Gulf Coast, human population is expected to increase in the coming decades. Large tracts of undeveloped land along the Gulf Coast identified as palustrine wetlands are prime targets for conversion to the human built environment. The conversion of habitat is influenced by a mix of regulatory and non-regulatory management decisions and activities.

An initial assessment of land use/land cover data recently released by the NOAA Coastal Change Analysis Program (C-CAP) indicates that palustrine wetland habitat may be under greater stress than estuarine wetlands in some areas along the Gulf Coast due to increasing development pressure.

CSWGCIN assessed the impact of coastal development and other stressors on the distribution of palustrine and estuarine wetlands in the Gulf of Mexico Coastal Zone. The displayed land use/land cover maps and change analysis charts details the changes in distribution of wetland habitats along the Gulf of Mexico Coast between 1996 and 2005.

The NOAA C-CAP land cover classification is based on Landsat Thematic Mapper satellite imagery. The data have a spatial resolution of 30meters and a target accuracy of 85%. C-CAP data are mapped at 1:100,000 scale with 22 standard classes representing major landscape types. C-CAP classification is supported by ground truthing and the use of supplementary data such as U.S. Geological Survey (USGS) topographic maps, Topologically Integrated Geographic Encoding and Referencing system (TIGER) road data, and National Wetland Inventory (NWI) data. In an effort to be consistent with wetland classifications prepared by other agencies, the wetland data included in the C-CAP Coastal Land Cover Classification System are based on the Coward in Wetland and Deep water Habitats classification developed in 1979. Detailed information describing the C-CAP methodology can be found online at http://www.csc.noaa.gov/crs/lca/pdf/protocol.pdf.

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