Grazing Modifies Woody and Herbaceous Components of North Queensland Woodlands.

Abstract

Grazed and exclosed areas within north Queensland woodlands were studied over a six-year period which included a drought followed by an above average rainfall period. Despite drought conditions, woody plant density increased, with exclosed areas showing a greater increase than grazed areas. During the drought period, a pattern of herbaceous vegetation strips interspersed with bare areas developed. Standing dry matter and ground cover increased rapidly in response to above average rainfall following the drought. Also, the pattern of strips became less apparent during the more favourable growth conditions. The percentage contribution of native tussock grasses (principally Heteropogon contortus) to total pasture dry matter varied to a greater extent over the six-year period than the naturalised stoloniferous Bothriochloa pertusa.