The influence of grazing by sheep on the structure of a saltbush (Atriplex vesicaria Hew. ex Benth.) population.

Abstract

The population structure of a stand of saltbush (Atriplex vesicaria Hew. ex Benth.) was studied within one paddock by sampling the shruLq3opulationon a grid radiating from the only watering point. The pattern of both contemporary and cumulative grazing influence was found to be focussed on the watering point but it was not a simple symmetrical one. The existence and distribution of preferred grazing areas could not be explained by the data collected. There was a preferential grazing pressure of the female shrubs. The cumulative effects of this were reflected in a five-fold change in the sex ratio (males/females) of the shrub population.