Cattle grazing in a hummock grassland regenerating after fire: the short-term effects of cattle exclusion on vegetation in south-western Queensland

Abstract

In the Simpson Desert of western Queensland fire is being used increasingly by pastoralists to manipulate hard spinifex (Triodia basedowii) pastures. In this study I investigated the short-term (20 month) effects of cattle grazing on hummock grasslands regenerating after fire in the Simpson Desert. Dung counts were used to determine if cattle grazed preferentially in areas regenerating after fire. Cattle exclosures and vegetation surveys were used to determine if grazing by cattle affected the structure and species composition of vegetation regenerating after fire.Cattle grazed preferentially in areas regenerating after fire. Cattle grazing reduced the cover, height, vertical density and species richness of regrowth vegetation. Grazing reduced the cover of Ptilotus polystachyus and reduced the proportion of Eragrostis eriopodia individuals bearing flowers and seed. Grazing visibly disrupted microbiotic soil crusts. It is recommended, as a precaution until additional data is available, that areas regenerating after fire be rested from grazing during the first post-fire wet season. Resting during this period will assist the establishment of vegetation cover and provide opportunities for grasses to set seed.