The role of grazing management in the functioning of pasture ecosystems

Abstract

This thesis reports what is thought to be the first scientific analysis of the comparative effects of cell grazing and continuous grazing on botanical composition and soil physical properties undertaken in Australia. Vegetation change in grasslands is a dynamic process and involves both the recruitment of individuals from the seed bank and the loss of individuals and species from the community through mortality. Recruitment from the seed bank at two of the sites studied far exceeded most previous reports. At both sites small-seeded species dominated the seed bank, and there was a poor relationship between the composition of the seed bank and the existing vegetation. The findings indicated that there was a high potential for regression of the botanical composition to rushes and annual dicots if inappropriate management practices were imposed or extended periods of stress were experienced. Perennial grasses comprised only 26% and 16% of the seedling recruitment from soil cores collected from the two sites respectively.