Tammar Wallaby - Population Dynamics and Conservation

Population Dynamics and Conservation

The tammar wallaby is listed as of Least Concern by the IUCN, due to its abundance and presumably stable population. However, the fragmentation of its range has led to high amounts of inbreeding and morphological abnormalities in some populations.

Since European occupation, tammar wallaby populations on both mainland Australia and some of the islands have been greatly reduced or even eradicated. In the early 20th century, the mainland population of tammars in Western Australia was described as numerous in much of the south-west, but declining in the cultivated areas, particularly to the north. Clearings made for wheat and sheep caused the population to decline further. From the 19th century, tammars in the Eyre Peninsula and around Adelaide were decimated by mobs of hunters organised to protect crops and pastures. As a result, they were extinct in the areas around Adelaide by the 1920s, and in the Eyre Peninsula around the 1970s. Tammars from Flinders Island and St Peter Island were eradicated in a similar manner.

Tammars from these areas were introduced to Kawau Island in New Zealand by colonial administrator Sir George Grey in 1870. Since then, they have flourished to the point where their foraging has damaged indigenous plants. Pest control operators have used sodium fluoroacetate, a naturally occurring rodenticide, to control their populations, a practice which has been controversial due to its possible effect on organisms not targeted, including humans. Cyanide pellets have been used as an alternative. In 1985, tammars were introduced to the North Island of the Houtman Abrolhos and have made similar impacts on native vegetation. Their numbers grew to 450 individuals, but by 2008 culling efforts appeared to have reduced their numbers to 25 individuals. In 2003, the Monarto Zoo temporarily housed 85 tammars from New Zealand awaiting reintroduction to the Yorke Peninsula in Innes National Park. Four releases have been made, and a stable wild population of 100–120 animals now exists. Tammars have also been successfully translocated to other areas, such as Nambung National Park and Avon Valley National Park.