Effects of recent changes in grazing and fertiliser management on the species richness of native ground-storey vegetation, Northern Tablelands, New South Wales

Abstract

Despite major land use changes, much of the ground-layer vegetation on the Northern Tablelands of New South Wales is still dominated by native grasses. The native grassy ecosystems of the region were studied to determine the impacts of grazing, fertilising and cultivation history on vascular plant species richness. Sampling was stratified on the basis of management. The incidence of all plant species in 30 m² quadrats was recorded at 373 sites within a 60 km radius of Armidale. Sites with a history of cultivation were found not to contribute any additional native species to the total number of native species found in uncultivated sites. In sites with no history of cultivation or fertiliser, the never grazed and infrequently grazed sites had significantly higher native species richness than grazed sites. The combined effects of increasing grazing intensity and fertiliser inputs significantly reduced native species richness and increased exotic species richness.