Species Diversity of Woody Vegetation in the Trinity River Basin, Texas

Species diversity was determined for 53 woody plant communities within the Trinity River Basin, Texas, using the Shannon-Weiner Diversity Index. Trees with diameters of 1 cm or greater at about 1.4 m above ground were measured. Community species diversity was correlated with a precipitation gradient associated with the basin. The general hypothesis that community species diversity increases with lessening stress was substantiated. Less moist upper basin and the more moist lower basin and swamp communities had lower species diversity values than the moist mid-basin communities.