Aboriginal man as an exterminator of Wallaby and Kangaroo populations on Islands Round Australia

The occurrence of kangaroos, wallabies and related species (Family Macropodidae) on islands of area 90 ha or more round Australia is non-random. Few islands adjacent to the northwestern, northern and eastern coasts have macropods present in contrast to a large number of islands near the mid-and southwestern coasts and most of the southern coastline. The latter group of islands was not visited by aborigines because they lacked watercraft, and most of the islands were apparently too small to support human populations. It is argued that Aboriginal man, through direct predation, his introduction of the Dingo, and his frequent use of fire, was chiefly responsible for the difference in representation of macropods on the two groups of islands.The median area of islands with at least one macropod species present and which are used by Aborigines is about six times larger than that of islands with at least one macropod species present and not visited or occupied by Aborigines. Several possible alternative hypotheses to account for the distribution pattern described above are discussed. For two of these hypotheses inadequate data are at hand to assess their significance.It is suggested that the median area of islands visited or occupied by Aborigines provides a guide to reserve sizes necessary for the conservation of macropods on mainland Australia. Areas of at least 5,000 ha are probably needed for the local long-term persistence of at least one species of macropod, and areas of 9,000 ha for the long-term survival in reserves of at least two macropod species.