Stress or disturbance caused much greater changes in catabolic evenness in the crop soil (low catabolic evenness) than the pasture soil (high catabolic evenness). Increasing Cu or salt stress caused increases in catabolic evenness at low intensities in both soils, but, in the crop soil, greater stress caused greater declines in catabolic evenness. Declines in pH also caused much greater decreases in catabolic evenness in the crop than the pasture soil. Catabolic evenness initially increased with increasing numbers of wet–dry or freeze–thaw cycles, but after four cycles, evenness declined in both soils. These changes in evenness could be attributed to significant changes ( P <) in most catabolic responses. In contrast, there were generally few changes in microbial biomass C as a result of stress or disturbance treatments. Except for EC stress, all treatments caused slight increases in biomass C at low levels (only significant in the pH and Cu treatments) that subsequently diminished at the highest stress or disturbance levels. Microbial catabolic diversity generally followed the classical ‘hump-back’ responses of diversity to increasing stress or disturbance. We concluded that reduction in catabolic diversity and changes in soil properties due to land use could reduce the resistance of microbial communities to stress or disturbance.