Identifying multiscale habitat factors influencing koala (Phascolarctos cinereus) occurrence and management in Ballarat, Victoria, Australia
Stephanie R. Januchowski1, Clive A. McAlpine2, John G. Callaghan3, Carol B. Griffin4, Michiala Bowen2, Dave Mitchell5 and Daniel Lunney6
1Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University (Townsville, Qld 4811, Australia; Tel.+61 (0) 7 4781 6024; Email: stephanie.januchowski@jcu. edu.au).
2School of Geography, Planning and Architecture as well as The Ecology Centre, The University of Queensland (Brisbane, Qld 4072, Australia).
3Gold Coast City Council (PO Box 5042, Gold Coast Mail Centre, Qld 9729, Australia).
4Department of Biology, Grand Valley State University (1 Campus Drive, Allendale, MI 49401, USA).
5The Australian Koala Foundation (GPO Box 2659, Brisbane, Qld 4001, Australia)
6Department of Environment and Conservation NSW (PO Box 1967, Hurstville, NSW 2220, Australia) and the School of Biological Sciences and Biotechnology, Murdoch University (Murdoch, WA 6150, Australia).
Modelling for the conservation of koala (Phascolarctos cinereus) populations has primarily focused on natural habitat variables (e.g. tree species, soil types and soil moisture). Until recently, limited consideration has been given to modelling the effects of the landscape context (e.g. habitat area, habitat configuration and roads). Yet, the combined influence of natural habitats and anthropogenic impacts at multiple spatial scales are likely to be important determinants of where koala populations occur and remain viable in human-modified landscapes. The study tested the importance of multiscale habitat variables on koala occurrence in Ballarat, Victoria, Australia. The models focused at three spatial scales: site (< 1 ha), patch (1–100 ha), and landscape (100–1000 s ha). Logistic regression and hierarchical partitioning analyses were used to rank alternative models and key explanatory variables.
The results showed that an increased likelihood of koala presence in fragmented landscapes in the urban–forest interface (as opposed to larger blocks of forest habitat) can best be explained by the positive effects of soil fertility and the presence of preferred koala tree species in these fragmented areas. If koalas are to be effectively conserved in Ballarat, it is critical to (i) protect remaining core areas of high-quality habitat, including regenerating areas; (ii) protect scattered habitat patches which provide connectivity; and (iii) develop and implement habitat restoration programmes to improve habitat connectivity and enhance opportunities for safe koala movement between habitat patches intersected by main roads.