Drought‐Associated Mortality of Range Grasses in South Texas

The effects of a 2—year drought on native grasses in South Texas were investigated on the Welder Wildlife Foundation Research Area during the summer of 1963. The percentage mortality on Victoria clay, Nueces fine sand, and Miguel find sandy loan was determined for seacoast bluestem (Andropogon scoparius Michx. var. littoralis (Nash) Hitch.), silver bluestem (Andropogon saccharoides Swartz var. longipaniculata Gould), filly panicum (Panicum filipes, Scribn.), buffalograss (Buchloe dactyloides (Nutt.) Engelm.), Pan American balsamscale (Elyonurus tripsacoides Humb. and Bonpl.), and brownseed paspalum (Paspalum plicatulum Michx.). Mortality ranged from an average low of 3407% for silver bluestem on Victoria clay to an average high of 76.8% for seacoast bluestem on Miguel fine sandy loam. Differences in percentage mortality between soils and between species on given soil types were highly significant. Mortality among individual clones ranged from 0% to 100%. In some instances a significant positive correlation existed between size of grass clones and percentage mortality. As diameter of clones increased, percentage mortality increased.