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Changes in Baccharis pteronioides and Haplopappus tenuisectus densities in a southeastern Arizona grassland were related to patterns of livestock grazing, fire, and precipitation. Results suggested that both species increased following two periods of relatively wet winters, and declined during an intervening dry period. Baccharis completely recovered through vegetative regrowth in one year after a 1987 wildfire, but Haplopappus suffered nearly total fire-caused mortality, and had not recovered by 1995 compared to its abundance on a nearby unburned site. In 1995, both species were most abundant in areas protected from grazing. Long-term (1982-1995) densities of Baccharis were stable, but Haplopappus density increased by more than two orders of magnitude over the same period, except in the burned area.