Population Fluctuations and Range Community Preference of Red Kangaroos in Central Australia

Abstract

(1) The distribution of red kangaroos, Megaleia rufa, was determined from aerial surveys at approximately 3-weekly intervals over a 41 year period, during which climatic conditions varied from drought to the wettest on record. The study area in the arid rangelands of central Australia was approximately 158 km2 and contained a complex diversity of grassland, Mulga shrubland and woodland communities. (2) Numbers of kangaroos on the paddock ranged up to 564, seven times the long-term mean of 81, during the drought period, and fluctuated between 9 and 204 at other times. These smaller changes in numbers occurred frequently between surveys as kangaroos moved into and out of the paddock in response to changes in forage conditions due to sporadic rains or fire. (3) The Mulga-annual grass community received the greatest average use by kangaroos, followed by Mulga-perennial grass and Open woodland. Less use was made of Flood plains, Gilgaied plains, Foothill fans, and several minor communities. The Treeless Plains communities and Open woodland were used by kangaroos as a refuge during drought and were little used during good forage conditions, while Mulga-perennial grass community showed an opposite trend in relative use. The Mulga-annual grass community, however, did not show any consistent trend with changes in forage conditions. (4) Results indicate that kangaroos are nomadic in response to changing forage conditions and their home range greatly exceeds the area of the study site.