Drought effects on a semidesert grassland range

TitleDrought effects on a semidesert grassland range
Publication TypeJournal Article
Year of Publication1972
AuthorsHerbel C.H., Ares F.N., Wright R.A.
Date Published1972
Keywordscover composition, drought effects, semidesert range, species composition
AbstractA vegetational survey on the Jornada Experimental Range in southern New Mexico, taken annually from 1941 through 1957, is the basis for a study of the effects of the great drought of 1951 through 1956. Both cover and yields were studied. Observations were stratified into seven classes based on a consideration of landform and soil characteristics. Seasonal and annual precipitation during the drought averaged 55% of the pre-drought average. The most severe drought years were 1951, 1953 and 1956. Both the cover and yield of Bouteloua eriopoda (Torr.) Torr., the dominant species on the upland sandy soils, were greatly reduced by drought. However, drought damage was much more severe on the deep than on shallow sands. When the impermeable caliche layer occurred at shallow depths, moisture relations during drought were apparently much better than when caliche occurred at greater depths. Another result of drought was the invasion of Prosopis juliflora (Sw.) DC. in areas where grass stands have been thinned by drought. Sporobolus spp. and Aristida spp., minor components of the climax, were more susceptible to drought damage than Bouteloua eriopoda. Yields of perennial grasses per unit cover were as great during the drought as prior to the drought. Both winterspring and summer precipitation are important in preventing death losses of black grama. In arid areas, it seems necessary to consider both cover and species composition in arriving at a potential for a site.