Grazing Management on Seeded and Unseeded Post-Fire Public Rangelands1

Public land management agency standard policy has been to delay grazing on burned areas for a minimum of 2 yr on both seeded and unseeded areas. This 2-yr grazing moratorium has not been specifically validated by research. Study objectives were to investigate seeding and not seeding as well as grazing and not grazing immediately after a fire. The study area was located on a fire-impacted Bureau of Land Management allotment in central Nevada that was divided into 4 large blocks. Treatments were imposed in a 2 × 2 × 2 factorial arrangement. Factors were seeded or unseeded, grazed or ungrazed, and 2 growing seasons. Grazing treatments were implemented in 2000, without pastures being rested. Post-treatment data was collected in 2001 and 2002. Baseline data indicated no difference between the 4 treatment areas. Fifty-three species of plants occurred in the area after the burn and 40 species in 2002. For the 2001 and 2002 analyses, total grass and shrub cover and density were not different. Forb cover was not different. Forb density was lower in grazed areas (P = 0.04). Forb density tended to be lower in 2001 than 2002 (P = 0.09) and lower in unseeded treatments, although no forbs were included in the rehabilitation seed mix. Cheatgrass density was lower in 2001 than 2002 (P = 0.03). Mean species richness decreased from 2001 to 2002 and was greater in the unseeded treatment (P = 0.04). There were no differences in diversity index values or percentage of similarity. For this study, grazing and aerial seeding had no effect on plant community response after fire.