The influence of climate, soil, and management on the composition of native grass pastures on the central, southern, and Monaro tablelands of New South Wales

Abstract

Pastures on 126 properties on the central, southern, and Monaro tablelands were surveyed to determine their botanical composition. Data on climate, soils, pasture sowing, fertiliser history, and stock management were collected to relate current composition to environmental factors and previous management. Native grass-based pastures were found to be widespread, and in many cases, pastures were dominated by native grasses, despite many decades of pasture improvement. Seventeen genera of native perennial grasses comprising over 35 species were identified. The most common species on the central tablelands were Austrodanthonia spp., Bothriochloa macra , and Microlaena stipoides ; on the southern tablelands, Austrodanthonia spp. and M. stipoides ; and on the Monaro, Poa spp., Austrodanthonia spp., Themeda australis , and Austrostipa spp. Soil type was the most important factor affecting species distribution, and other soil attributes such as texture, pH, P, and N were also important. Environmental (rainfall) and management (superphosphate application, stock type, stocking rate) factors also influenced distribution. The significant areas of native grass pastures that were found suggest a decline in sown species and a recolonisation of sown pastures with native grasses. The potential for manipulation of botanical composition of these grasslands is discussed, together with their value for production and sustainability.