Poster presentation 12th International Mammalogical Congress

Periodic movement patterns by a specialist herbivore, the koala, in a patchy landscape (#758)

Adrian Rus 1 , Clare McArthur 1 , Mathew Crowther 1
  1. University of Sydney, Camperdown, New South Wales, Australia

As animals move across the landscape to satisfy their nutritional needs, movement patterns emerge, painting a picture of the areas they visit. In some species, these movement patterns may be repeated temporal scales. Specialised herbivores have been argued to be ritualistic, and from a foraging perspective this could be manifest in periodic movement patterns with animals moving regularly and predictably through their landscape to harvest food. We aimed to test this prediction for a specialist herbivore, the koala (Phascolarctos cinereus), across different temporal scales within a patchy landscape. Associated with efficient foraging, we also predicted koalas would revisit large and clustered foraging patches more frequently than small isolated patches. Our study sites were on highly fragmented eucalypt woodland in the Liverpool Plains, New South Wales, Australia. We tracked 20 koalas for five months with GPS collars from 2015-2016. We used biased random bridges to determine foraging patches frequently visited by koalas. Then we used Fourier transforms to determine the periodicities of revisits and wavelet analysis to determine whether those periods were consistent across the time series. The results of our analysis showed that koalas periodically revisited foraging patches every 14 days and that larger foraging patches were revisited between 5 to 6 days. These findings provide an insight into periodic space use by foragers, and support the hypothesis of ritualised feeding patterns by a specialist herbivore. The next step is to determine why animals revisit food patches at a particular periodicity.