Overabundant kangaroos: concerns, causes and cures Graeme Coulson School of BioSciences Macropus Consulting Types of overabundance Abundance — Impact 1. Threaten human life or livelihood 2. Depress other favoured species 3. Too numerous for their own good 4. Above equilibrium density (Caughley 1981) Threats to humans Threats to humans Threats to humans Depress other species 4000 3000 2000 Hooked Aabundance 1000 Needlewood 0 Hattah-Kulkyne National Park 1982 1984 1986 1988 1990 Depress other species 1200 120 Kangaroos 1000 Bandicoots 100 800 80 600 60 400 40 Bandicoot captures Bandicoot Kangaroo abundance Kangaroo 200 20 0 0 1990 1992 1994 1996 1998 Year Eastern Woodlands Historic Park Barred Bandicoot Poor welfare Body condition Reproduction 14 50 12 40 10 8 30 6 Fat (%) Index Fat 20 4 % females breeding % females 10 Kidney 2 0 0 2007 2009 5.0 2007 2009 4.0 /ha) 3.0 roos ( 2.0 1.0 Density 0.0 Serendip Sanctuary 1996 1998 2000 2002 2004 2006 2008 2010 Year Poor welfare Lumpy jaw 54% prevalence Serendip Sanctuary Above equilibrium Stabilisation Decline Post-decline Increase ‘irruption’ Population density Population Time Above equilibrium Puckapunyal Military Area Regulation bottom up Serendip, May 2006 RegulationPopulation irruptions Serendip, May 2006 Solutions? Population density bottom up Exclusion Direct effect Small scale Maintenance? Defence Establishment Orchard Hills Deterrence Different senses Relevant stimuli? Desirable response? Habituation? Fertility control Indirect effect Long-acting? Delivery? Marking? Predators Large scale Direct effect Indirect effect Unintended effects? Wilsons Promontory National Park Culling Direct effect Last resort Humane? Managing overabundance • Overabundance has multiple effects • Irruptions seem to be inevitable • Early actions are essential Population density Thank you Australasian Wildlife Management Society Dept. of Environment, Land, Water & Planning Dept. of Zoology, University of Melbourne Independent Panel of Experts Kangaroo Advisory Group, ANGAIR Kangaroo Technical Advisory Committee Koala and Kangaroo Contraception Program Parks Victoria Territory and Municipal Services Zoos Victoria .