although the majority of these flats were bare, vegetated areas included shoregrass (Monanthochloe littoralis), quelite (Atriplex arenaria), and glassword (Salicornia virginica). The laguna matrix zone consisted of ex- tensive tidal flats composed of mud and sand that were found along the western edge of the island adjacent to the Laguna Madre. Within the north- ern portions of paiS, these seemed to be limited to four ponds, which were located at Bird island Basin (pond a), 0.8 km south of the headquarters building (pond B), and 1.0 km east south-east of the Malaquite Beach Visitor Center (pond C and the waste water treatment pond Fig. permanent sources of freshwater within paiS were scarce. The salinity of these wet- lands varied, which resulted in floral communities that contained species tolerant of both fresh and salt water (national park Service 2008b). Within the flats, storm water collected in depressions to form wetlands dominated by plants such as bulrush (Scirpus pungens and Sciprus americanus), southern cattail (Typha domingensis), and the exotic giant reed (Arundo donax). The interior zone was the single largest terrestrial zone within paiS ( Ramsey et al. The coastal prairie is the southernmost unit of the tallgrass prairie biome in north America ( Diamond and Smeins 1984), and climatically it ranges from humid and sub-humid in the north to sub- humid and semi-arid in the south (Thornthwaite 1948 Diamond and Smeins 1984). The interior zone consisted of vegetated flats of coastal prairie dominated by bushy bluestem (Andropogon glomeratus), seacoast bluestem, plains wild indigo, and gulfdune paspalum (Paspalum monostachyum). Behind the dune system was a relatively low lying zone composed of various habitats. These dunes are fairly well stabilized by vegetation, except where vegetation had been removed by wind, water, or human activity (Drawe and Kattner 1978 Judd et al. although dunes can be found throughout pa- dre island, they are concentrated adjacent to the beach.

The interdune was a low lying area located between the foredune and primary dune, and shared similar vegetation with both dune habitats.

When present, the interior dunes had vegetation similar to the primary dune, but they were generally smaller. The larger primary dune was located more inland and was typically dominated by grasses including seacoast bluestem (Schizachyrium scoparium) and sea oats, in addition to plains wild in- digo (Baptisia leucophaea). The foredune was immediately adjacent to the beach and was dominated by morning glory (Ipomoea imperati and Ipomoea pes-caprae), in addition to sea oats (Uniola paniculata) and beach tea (Croton punctatus).

This dune system was subdivided into four zones including foredune, interdune, primary dune, and interior dune. of the beach was a ridge of vegetated coastal sand dunes.

National seashore texas