Estimation of the Density of Feral Goats in Part of Arid South Australia by means of the Peterson Estimate

Abstract

The density of feral goats in about 234 km2 of arid rangeland used for sheep grazing in South Australia was estimated by means of a mark-resight technique. Marking and subsequent resighting were done at watering points. The Petersen estimate was 4.4 goats per square kilometre; adjustment to allow for nonrandom behaviour raised this estimate to 5.0 km-1. Maximum allowable sheep density is 12 km-2. The goat density we observed imposes an added burden on the vegetation. The densities of red and western grey kangaroos, when added together, approximate that of the goats. Rabbits are virtually absent. The long-term effects of the total grazing pressure on the vegetation cannot be predicted in detail but will probably be deleterious.