PARENT SESSION
Poster Session #27: Salt Marshes.
Wednesday, August 8, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Composition and structure of a west Texas salt marsh.

Van Auken, Oscar¹, Brown, Steven¹, ¹

ABSTRACT- An inland salt marsh is found along Leon Creek in the Diamond Y Spring Preserve in Pecos County near Fort Stockton, Texas. The composition and structure of the marsh are previously unreported. Chihuahuan Desert communities dominated by creosote bush are found on shallow upland soils and other communities dominated by honey mesquite are on deep soils. Fourteen linear transects were established to cross the marsh from north to south. Transects were 50 m apart and 250 to 480 m long. Plant cover was estimated in 0.1 m quadrats at 5 m intervals along each transect. Mean plant cover was 80%. Mean species cover (±SD) of saltgrass was highest at 33±32%. It was followed by alkali sacaton at 22±31%, Pecos or puzzle sunflower at 12±26%, seepweed at 7±14%, and bulrush at 3±11%. Sea lavender, Texas sporobolus, and yellow flaveria cover was 1% each. Seven other species had cover values less than 1% (15 total species found). As one descends slightly in elevation into the marsh from the dry upland, three plant communities are encountered. From driest to wettest, the sequence is an alkali sacaton grassland, a saltgrass grassland, and in the drainage a bulrush marsh community. The communities are simple, composed of few species (6 to 11). Soil water content, salt levels, oxygen levels, and disturbance or herbivory are probably factors controlling the cover and composition of the communities.

KEY WORDS: inland salt marsh, threatened species, pecos sunflower, puzzle sunflower