PARENT SESSION
Oral Session #104: Plant Communities: Vegetation Analysis.
Presiding: S. Will-Wolf
Friday, August 9. 9:00 AM to 12:00 PM. Grand Ballroom West, Radisson.
Comparison of upland woody plant communities in a Chihuahuan desert salt marsh.
Hart, Dianne*,1, Van Auken, Oscar1, 1 University of Texas at San Antonio, San Antonio, Texas
ABSTRACT- The Diamond Y Spring Preserve, owned by the Nature Conservancy of Texas, is located in the Chihuahuan desert near Fort Stockton, Texas. The spring and drainage area support several federally endangered and threatened species, including Helianthus paradoxus, the puzzle sunflower. Vegetation in the Preserve appears to exist in discrete bands with little intergradation from the lower areas to the areas of higher elevation. The upland woody communities comprised primarily of Prosopis glandulosa on deeper alluvial soils at lower elevations and Larrea tridentata on shallow rocky soils at higher elevations were compared in terms of phytosociological characteristics of density, canopy area and frequency and for soil characteristics of depth, salinity, anions and cations. Ten transects were located in each community. Herbaceous vegetation and rock cover was measured in each quadrat along each transect. An elevation study was also conducted in order to measure change in cover type along elevation gradients. Significant differences were found in all soil parameters with the exception of Ca. While woody plant density was greater in the Larrea communities, canopy area was greater in the Prosopis communities. The number of woody species present was greater in the Larrea areas (23) than in the Prosopis communities (15).
KEY WORDS: chihuhuan desert, prosopis glandulosa,