Patchy resources and multiple threats: How do koalas navigate an urban landscape?

Urbanisation is increasing throughout the range of the koala (Phascolarctos cinereus) and has contributed to the decline of koala populations in many areas. In urban landscapes where koalas may need to travel considerable distances to access resources, they face increased risks of predation by domestic dogs and vehicular collision. Understanding how koalas navigate this risky landscape is key to developing effective conservation strategies. We used GPS data collected from 20 koalas to examine koala habitat use and movements in an urbanised area of the Mornington Peninsula, Victoria, Australia. Koala home ranges were large (males = 9.1 ha, females = 4.3 ha) and covered up to 153 properties. Analysis of GPS tracks showed that koalas moved frequently (median number of different locations per week: 14 [males], 8 [females]), usually over short distances (median distance: 69 m [males], 50 m [females]), and often crossed roads (average crossings per week: 9.4 [males], 2.7 [females]). Despite this movement behaviour placing koalas at risk of vehicular collision and predation by dogs, we recorded only three deaths during the one-year study period; two were due to old age and one of unknown cause. Our low mortality rate may be due to movements occurring at night when risks may be lower, and high awareness in the community about koalas that mitigates threats. Our results suggest that effective conservation of urban populations of koalas requires a landscape-scale approach with participation by the community and public land managers to maintain and establish koala habitat and connectivity, and to encourage koala-friendly driving behaviour.