Sydney's bubonic plague outbreak 1900-1910: a disaster for foreshore wildlife?

The foreshore of Sydney Harbour includes extensive areas of protected native bushland that are an iconic and world-renowned feature of the Sydney landscape. Despite this vegetative cover, however,native small mammals are uncommon and the bushland is dominated by introduced Black Rats Rattus rattus. In particular, the Bush Rat Rattus fuscipes is absent yet remains abundant in comparable habitats to the north and south of Sydney; the last record of the Bush Rat near Sydney Harbour is from 1901. In this paper we explore the idea that the arrival and spread of bubonic plague in the port City of Sydney between 1900 and 1910 was a primary cause of the extirpation of Bush Rats around the harbour foreshore. The plague killed 181 people in Sydney during three major outbreaks,and also killed hundreds of thousands of rats and 52 native Australian mammals in the Moore Park Zoo. The ensuing hysteria and fear of plague resulted in a determined campaign to rid Sydney of rats, including the introduction of a rat bounty. This campaign led to the culling of a further 100,000 rats, both native and introduced, including "bush rats". We suggest that Bush Rats were wiped out from the harbour foreshore by the direct effects of the plague and the indirect effects arising from rat persecution to prevent plague, making the arrival of bubonic plague in the 1900s a disaster for Sydney's foreshore wildlife. If this hypothesis is correct, then future attempts to restore Bush Rats to the harbour foreshore will not be hampered by the cause of their absence, as Australia is currently free from plague.