The Influence of Sheep on Pattern and Process in Atriplex vesicaria Populations From the Riverine Plain of New South Wales

Abstract

The application of multiple pattern analysis (multiscale ordination) to a phase-differentiated sample of perennial saltbush (Atriplex vesicaria) rangeland, along with assessments of the vegetative and reproductive states of individual plants, served to indicate the importance of sheep in determining some scales of distributional pattern in the shrub population. By comparison with conventional pattern analysis, it is shown that multiple pattern analysis can be used to provide an economic description of 'total' pattern in temporally related phases of a monospecific plant population. It is demonstrated that the pattern-determining interaction between sheep and saltbush individuals is dependent on plant size, sex and location with respect of other shrub individuals, in particular due to the trampling of seedling and pioneer phases and the selective grazing of sexually mature shrubs by sheep.