Wetland Plant Communities, Galveston Bay System

Wetlands and aquatic habitats are critical components of the biologically productive Galveston Bay estuarine system. This report is the culmination of a field investigation of wetland plant communities and is one phase of the project "Trends and Status of Wetland and Aquatic Habitats of the Galveston Bay System, Texas," sponsored by the Galveston Bay National Estuary Program (GBNEP). For purposes of this topical report, wetlands are defined and classified in terms of more classical definitions, for example, salt, brackish, and fresh marshes, in accordance with project requirements. The relationship of these wetland classes to the Cowardin and others (1979) classification system used to map wetlands is presented through various examples. Wetlands in this study were not defined in accordance with the "Federal Manual for Identifying and Delineating Jurisdictional Wetlands" (currently being revised) and thus should not be regarded as jurisdictional wetlands.

More than 150 sites were examined in the Galveston Bay system. Wetland plants were identified at selected field survey sites, principally along transects aligned perpendicular to the hydrologic gradient so that plant assemblages from the water's edge to upland areas were intercepted. Topography surveys were conducted along several transects. Measurements of elevation, distance, and plant community composition were made along the survey lines, which crossed salt marshes and brackish to fresh marshes. Elevations were measured to the nearest 0.5 cm and distances to the nearest meter. County soil surveys were used to define and characterize soils at the various field check sites. The locations of field survey sites were plotted on aerial photographs and later accurately transferred to USGS 7.5-minute quadrangle topographic maps. Universal Transverse Mercator (UTM) coordinates were determined for each site, and these data were entered into computer data management systems, including the geographic information system, ARCsINfO.