TRENDS IN NUMBERS AND CHANGES IN THE DISTRIBUTION OF FERAL GOATS (CAPRA-HIRCUS) IN THE SOUTH AUSTRALIAN PASTORAL ZONE

Trends in numbers and changes in the distribution of feral goats in th e South Australian pastoral zone (217300 km(2)) during 1978-94 were de termined by winter aerial surveys. Only the presence or absence of goa ts on sample units was scored between 1978 and 1988. On the assumption of a random distribution of goat groups, these indices were transform ed to densities of goat groups. Between 1989 and 1994 actual goat numb ers were recorded on each sample unit, allowing goat density to be est imated. Goats were consistently at their highest densities in the sout h-east of the pastoral zone, a region dominated by open mallee scrub a nd chenopod shrubland. Densities of goat groups fluctuated from a low in 1984, following a drought, to a peak in 1990, following above-avera ge rainfalls, when there were an estimated 193 700 +/- 29 600 goats in the pastoral zone. This estimate is conservative because it is uncorr ected for the visibility bias associated with sighting groups and unde rcounting their sizes. The estimate also excludes the Flinders Ranges for which a similar number of goats has been estimated.