The drought of 1989 had profound effects on the Nevada Test Site. In some areas, no rainfall was recorded for more than a year. Mortality in short-lived species, such as perennial grasses, was high. In the old main road, no Achnotherum hymenoides remain. Instead, Hymenoclea salsola (cheesebush) is common, and Ephedra are more numerous. The conversion from short-lived grasses to more drought-tolerant shrubs is caused by drought. This type of drought-driven conversion may be one of the primary mechanisms driving vegetation recovery in severely disturbed sites. (Robert H. Webb)