DYNAMICS OF PERENNIAL GRASSES WITH SHEEP GRAZING IN ACACIA-ANEURA WOODLANDS IN SOUTH-WEST QUEENSLAND

The effects of grazing on the dynamics of perennial grasses in Acacia aneura woodland were monitored between 1978-1984. Sheep numbers were a djusted annually to utilise between 20-80% of the total forage availab le at the end of summer.Increasing pasture utilisation reduced the tot al basal area of perennial grasses and resulted in major shifts in the occurrence of individual grass species. Aristida spp. were the main s pecies under very heavy grazing. Variation in rainfall between years r esulted in large changes in total basal area and in the occurrence of individual grass species. It is concluded that long-term wool producti on (data not presented) commensurate with maintenance of the vegetatio n may be maximised by 20% rather than higher levels of utilisation.