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Gulf Barrier Islands and Coastal Marshes

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About the Gulf Barrier Islands and Coastal Marshes

The Gulf Barrier Islands and Coastal Marshes is a region of Barrier Islands and Coastal Marshes along the gulf coast, extending from the Mississippi Delta, through Mississippi and Alabama's coast, and along the Florida panhandle east to Ochlockonee bay.

This region is low-lying and consists of river deltas, tidal marshes, bays, lagoons, barrier islands, dunes, and beaches. Soils are formed variously on sand and shell fragments originating along the beaches, silt and clay coming from the rivers, and muck and peat derived from local decomposition of organic matter. Soils vary in their water retention, but tend to be acidic.

The climate is towards the mild end of a subtropical climate and moderated by the ocean. Precipitation is high year-round, but tends to peak in summer months; there is a brief, slightly drier season in October. The eastern end of this region has a second drier season peaking in May. This region is frequently affected by hurricanes and other severe coastal storms. Snow is rare, but possible. In a typical winter the climate dips below freezing occasionally but freezes are short-lived.

This region originally had, and still has, very different cover on the different sites. Dunes supported sea oats (Uniola paniculata) and some seaside goldenrod (Solidago sempervirens). On richer sites there were maritime shrub forests, with false rosemary (Conradina canescens), scrub oaks, and eastern baccharis (Baccharis halimifolia). The richest coastal sites supported maritime evergreen forest, with live oak (Quercus virginiana), Darlington oak (Quercus hemisphaerica), and slash pine (Pinus elliottii) and understories of sea oats. Salt and brackish marshes supported cordgrass, saltgrass, and rushes, whereas tidal freshwater marshes, more common to the west of this region, supported arrowhead, spikerush, and bulrush.

Nowadays the barrier islands been heavily developed along most of its length; there is significant urbanization and local population centers, mostly for recreation and vacation homes, but with significant permanent year-round residents as well. However, some of the less accessible barrier islands remain undeveloped and unpopulated, and others, less densely developed. There is also some public, protected land, including at Dr. Julian G. Bruce St. George Island State Park in Florida. Throughout the region there is also still significant marshland and forested wetland behind the barrier islands. The region is also important in commercial fishing and shellfish production.

Along most of its length, this region is bordered inland by the Gulf Coast Flatwoods, except along major rivers where it is bordered inland by the Floodplains and Low Terraces. At its east end, along the coast, this region is replaced by Big Bend Coastal Marsh. At its western end, it is bordered by the Deltaic Coastal Marshes and Barrier Islands of the Mississippi River Delta.

Plant Lists & In-Region Search

We do not yet have data to generate plant lists for a region as fine-tuned as this one. However you can move up to the broader Southern Coastal Plain and generate lists for that region: native plants or all plants. Or search that region's plants here:


1. Griffith, G.E., Omernik, J.M., Comstock, J.A., Lawrence, S., Martin, G., Goddard, A., Hulcher, V.J., and Foster, T. "Ecoregions of Alabama and Georgia (color poster with map, descriptive text, summary tables, and photographs)", U.S. Geological Survey, Reston, VA (2001) Web.