Temperate grasslands worldwide have been reduced to remnants as a result of urban, rural, and oil and gas activities. One of the largest remaining tracts of temperate grassland is located in central Alberta, Canada: a provincial protected natural area known as Rumsey Block. Although Rumsey Block has been protected from urban and rural development, oil and gas activities have been allowed. We analyzed the change in plant communities from several oil and gas disturbances over an eleven-year period. We developed a state and transition model displaying consequences of disturbances from grazing and oil and gas development on rough fescue grassland, considered the reference stable state. Transitions were no, light, or moderate grazing and minimum oil and gas disturbance, such as plow-in pipelines, small area well sites (<25 m²) and sites seeded with native species or left to natural recovery. Triggers, causing change from rough fescue grassland to altered states, were heavy grazing, and moderate to major oil and gas disturbances, such as topsoil stripping and seeding with introduced species. Within the reference state, three plant communities were identified, varying from rough fescue (Festuca hallii) grassland to grazing-induced variations where shortbristle needle and thread (Hesperostipa curtiseta) became dominant. Two altered states were identified: Introduced Grasses and Native Grasses. All altered states were deemed to have crossed a threshold requiring complete eradication of species and reseeding. Based on these results, we recommend minimum disturbance in grasslands, such as light grazing, plow-in pipelines, small areas well sites, and natural recovery.