Koalas &
the Little River
Koala Fact Sheet #1: Koalas & the Little River, Victoria
A few koalas persist near the Little River north of Balliang Creek, but their future is perilous. Targeted planting beside waterways – including the Little River and tributaries – could ensure their survival, and possibly re-colonisation downstream of the Balliang Creek to about 5km north of Little River township. This fact sheet and map explains where koalas are and why, their decline, threats, and solutions to ensure they have a future in the region.
Where are the koalas?
Wild koalas live in the Brisbane Ranges, You Yangs, and in the upper reaches of the Werribee River. These koala populations are fairly small and declining (1), but sightings are still possible. Few koalas live near, or move along smaller waterways in the district, including the Little River, Balliang, Parwan, Hovells & Sandy Creeks. (See map below)
Koala primary food trees in the district include Manna Gum Eucalyptus viminalis and River Red Gum Eucalyptus camaldulensis (2). Koala presence is strongly associated with these primary forests (3,4). Other species of eucalyptus may be eaten, and are important as secondary forage and shelter, but in 2025 few koalas live long-term in secondary forests.
This fact sheet was produced by Koala Clancy Foundation as a Melbourne Water Liveable Communities, Liveable Waterways Project.
Some forests that contain Manna and/or River Red Gum are no longer habitable for koalas, particularly near built-up areas where the effects of roads, dogs and human noise combine. Since 2015, Koalas have not been seen within 15km of Werribee, within 4km of Little River, or within 3.5km of Bacchus Marsh, though suitable trees exist.
Koalas are reliant on forest along watercourses, especially in times of drought and extreme heat. (5,6) In the Little River region, the native trees lining rivers and creeks are mostly River Red Gums on the plains, and Manna Gums on rocky streambanks in the ranges, both of which are primary food species for koalas. Forested creeks and rivers provide koalas with cooler microclimates on days of extreme heat, moist foliage to provide their water needs, and a linked corridor of vegetation to move through.
Koalas need large blocks of forest, containing many hundreds or thousands of trees. Landscape configuration, soil fertility and proportion of primary tree species is also important. (7, 8)
Populations and status
CSIRO National Koala Monitoring Program estimates Victoria’s koalas are in decline (1). Locally, recent research in Moorabool Shire found very little evidence of koalas (9), monitoring in the You Yangs has shown steep declines (10), and local knowledge in the Brisbane Ranges supports this.
Under a hotter and drier climate, koala populations in this region are predicted to shrink and move south and east – towards the Otways, & the forests east of Melbourne (11).
Do koalas travel far?
Koalas move around their home ranges through the year. Most koalas change trees every day, and can use up to 9 trees each night. (20) Home ranges in the district vary from 5 to 45 hectares.
Koalas may leave their home area to travel to another location for many reasons. Dispersing koalas can travel many kilometres. Most dispersing koalas are young males, but koalas of all ages and sexes can disperse (21).
Threats and solutions
Habitat deterioration: Leaf nutrition is reducing due to increased carbon in the atmosphere (12, 13). Leaves are drying out, trees are dying & losing condition. Fragmentation of habitat lowers koala fitness and shortens their lives (14). Solution: Well-planned revegetation can reconnect forests.
Road network: High speed roads with heavy traffic loads kill koalas (15). Solution: Fencing, educational programs, and over- and under-passes may be needed.
Built-up town areas: Koalas avoid areas with high noise (16), traffic and domestic dogs. Solution: Planting on farmland is ideal and safe.
Treeless areas: Large treeless areas are risky for koalas. Dogs, cattle & horses can kill koalas on the ground (17). Solution: Fencing-off shelterbelts, waterways and paddock trees improve their chances of survival.
Fires: High intensity fires in koala habitat can kill 70% to 100% of koalas (18), but healthy populations can re-colonise if nearby.
Disease: Chlamydia is present in the area, though Victorian koalas usually have milder signs (19). Environmental stress may lead to more severe disease. Solution: Planting new, fertile forests reduces environmental stress on koalas.
This fact sheet was produced by Koala Clancy Foundation as a Melbourne Water Liveable Communities, Liveable Waterways Project.
REFERENCES:
(1) CSIRO National Koala Monitoring Program: https://www.nkmp.org.au/populations.php
(2) Mitchell, D., 2015. National koala tree planting list. p 219 VIC: Greater Geelong. https://www.savethekoala.com/wp-content/uploads/2017/02/20150212_AKF_National_Koala_Tree_Planting_List.pdf
(3) Smith, A.G., McAlpine, C.A., Rhodes, J.R., Lunney, D., Seabrook, L. and Baxter, G., 2013. Out on a limb: habitat use of a specialist folivore, the koala, at the edge of its range in a modified semi-arid landscape. Landscape Ecology, 28, pp.415-426. https://doi.org/10.1007/s10980-013-9846-4
(4) Hindell, M.A. and Lee, A.K., 1987. Habitat use and tree preferences of koalas in a mixed eucalypt forest. Wildlife Research, 14(4), pp.349-360. https://doi.org/10.1071/WR9870349
(5) Smith, A.G., Mcalpine, C., Rhodes, J.R., Seabrook, L., Baxter, G., Lunney, D. and Bradley, A., 2013. At what spatial scales does resource selection vary? A case study of koalas in a semi‐arid region. Austral Ecology, 38(2), pp.230-240. https://doi.org/10.1111/j.1442-9993.2012.02396.x
(6) Gordon, G., Brown, A.S. and Pulsford, T.J.A.J.E., 1988. A koala (Phascolarctos cinereus Goldfuss) population crash during drought and heatwave conditions in south‐western Queensland. Australian Journal of Ecology, 13(4), pp.451-461. https://doi.org/10.1111/j.1442-9993.1988.tb00993.x
(7) McAlpine, C.A., Rhodes, J.R., Callaghan, J.G., Bowen, M.E., Lunney, D., Mitchell, D.L., Pullar, D.V. and Possingham, H.P., 2006. The importance of forest area and configuration relative to local habitat factors for conserving forest mammals: a case study of koalas in Queensland, Australia. Biological Conservation, 132(2), pp.153-165. https://doi.org/10.1016/j.biocon.2006.03.021
(8) Januchowski, S.R., McAlpine, C.A., Callaghan, J.G., Griffin, C.B., Bowen, M., Mitchell, D. and Lunney, D., 2008. Identifying multiscale habitat factors influencing koala (Phascolarctos cinereus) occurrence and management in Ballarat, Victoria, Australia. Ecological Management & Restoration, 9(2), pp.134-142. https://doi.org/10.1111/j.1442-8903.2008.00405.x
(10) https://www.koalaclancyfoundation.org.au/learn-about-koalas/koala-research/
(11) Adams-Hosking, C., Grantham, H.S., Rhodes, J.R., McAlpine, C. and Moss, P.T., 2011. Modelling climate-change-induced shifts in the distribution of the koala. Wildlife Research, 38(2), pp.122-130. https://doi.org/10.1071/WR10156
(12) Hovenden, M.J. and Williams, A.L., 2010. The impacts of rising CO2 concentrations on Australian terrestrial species and ecosystems. Austral Ecology, 35(6), pp.665-684. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1442-9993.2009.02074.x
(13) Lawler, I.R., Foley, W.J., Woodrow, I.E. and Cork, S.J., 1996. The effects of elevated CO 2 atmospheres on the nutritional quality of Eucalyptus foliage and its interaction with soil nutrient and light availability. Oecologia, 109, pp.59-68. https://link.springer.com/article/10.1007/s004420050058
(14) Rus, A.I., McArthur, C., Mella, V.S. and Crowther, M.S., 2021. Habitat fragmentation affects movement and space use of a specialist folivore, the koala. Animal Conservation, 24(1), pp.26-37. https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/acv.12596
(15) Taylor-Brown, A., Booth, R., Gillett, A., Mealy, E., Ogbourne, S.M., Polkinghorne, A. and Conroy, G.C., 2019. The impact of human activities on Australian wildlife. PloS one, 14(1), p.e0206958. https://doi.org/10.1371/journal.pone.0206958
(16) Rivera, P., 2020. Factors driving the distribution of the koala in a modified landscape (Doctoral dissertation, Deakin University). https://dro.deakin.edu.au/articles/thesis/Factors_driving_the_distribution_of_the_koala_in_a_modified_landscape/21116566
(17) Jiang, A., Tribe, A., Phillips, C.J. and Murray, P.J., 2021. Do livestock injure and kill koalas? Insights from wildlife hospital and rescue group admissions and an online survey of livestock–koala conflicts. Animals, 11(9), p.2684. https://www.mdpi.com/2076-2615/11/9/2684
(18) Phillips, S., Wallis, K. and Lane, A., 2021. Quantifying the impacts of bushfire on populations of wild koalas (Phascolarctos cinereus): Insights from the 2019/20 fire season. Ecological Management & Restoration, 22(1), pp.80-88. https://onlinelibrary.wiley.com/doi/abs/10.1111/emr.12458
(19) Legione, A.R., Patterson, J.L., Whiteley, P.L., Amery-Gale, J., Lynch, M., Haynes, L., Gilkerson, J.R., Polkinghorne, A., Devlin13, J.M. and Sansom13, F.M., 2016. Identification of unusual Chlamydia pecorum genotypes in Victorian koalas (Phascolarctos cinereus) and clinical variables associated with infection. Journal of Medical Microbiology, 65, pp.420-428. https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.000241
(20) Marsh, K.J., Moore, B.D., Wallis, I.R. and Foley, W.J., 2014. Continuous monitoring of feeding by koalas highlights diurnal differences in tree preferences. Wildlife Research, 40(8), pp.639-646. https://www.publish.csiro.au/wr/WR13104
(21) Dique, D.S., Thompson, J., Preece, H.J., de Villiers, D.L. and Carrick, F.N., 2003. Dispersal patterns in a regional koala population in south-east Queensland. Wildlife Research, 30(3), pp.281-290. https://www.publish.csiro.au/wr/wr02043
