Mammal declines in the Mitchell Subregion of the North Kimberley Bioregion, Western Australia as demonstrated by the history of disappearances at Kalumburu

The establishment of the Drysdale River Mission, near Kalumburu, Western Australia, in 1908 facilitated the early collection and documentation of the local mammal fauna and the Indigenous Knowledge associated with it. This review examines evidence of chronological changes in the historic status and range of Critical Weight Range (CWR) mammals in the study area (defined by a 45 km radius around Kalumburu) in the northern limit of the Mitchell subregion of the North Kimberley Bioregion, by comparing historic data with more recent data. It concludes that at least 27 species of CWR mammals occurred there, consistent with the wider hotspot. Of these species, several have apparently suffered local extinction or declines matching trends reported elsewhere in the region and across northern Australia. Two arboreal species (Brush-tailed Rabbit-rat Conilurus penicillatus and Golden-backed Tree-rat Mesembriomys macrurus) and a medium-sized ground-dwelling species (likely Spectacled Hare-wallaby Lagorchestes conspicillatus) disappeared in the early 1900s. A further five species persisted to the 1980s but are now likely to be locally extinct including Golden Bandicoot Isoodon auratus, Brush-tailed Phascogale Phascogale tapoatafa, Brush-tailed Possum Trichosurus vulpecula, Black-footed Tree-rat Mesembriomys gouldi and Savanna Glider Petaurus ariel. Another four species have experienced local declines and have disappeared from parts of the study area (Northern Quoll Dasyurus hallucatus, Nabarlek Petrogale concinna, Grassland Melomys Melomys burtoni and Northern Brown Bandicoot Isoodon macrourus). The study shows that the Biodiversity Hotspot is not immune to factors that have caused CWR mammals to decline in northern savannas and adds new knowledge to a poorly studied region of Australia.