Ecological Observations on Plant Communities Grazed by Sheep in Australia

Abstract

Before European settlement plant communities in Australia were in equilibrium with the climates and soils and were adapted to the relatively light and intermittent grazing of indigenous marsupials as well as to recurrent burning. The introduction of domestic livestock and rabbits by British settlers; the felling of timber for the purpose of increasing grass growth; the consequent defoliation, trampling and manuring by confined animals profoundly altered the environments of these communities. Concurrently with the introduction of livestock, seeds of alien plants entered the country either by design — as agricultural and horticultural seeds — or accidentally as impurities in crop and pasture seeds or attached to the hides of animals. These two factors, the disturbance of the equilibrium of our native vegetation, and the introduction of alien plants pre-adapted to such disturbed areas with their modified environments, have effected marked changes in Australian plant communities. These changes occurred rapidly and over a wide area of southern Australia as a result of the sharp increase in sheep numbers following the settlement of the pastoral country. By 1880 the whole of New South Wales was settled and by 1890 sheep numbers in Australia had reached the 100 million mark.KeywordsAlien PlantSubterranean CloverHeavy GrazingSheep GrazingHigh Rainfall AreaThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.