Australia's European Rabbit Invasion

When you hear the term "invasive species" you might think of a plant like the Kudzu - the vine that covers the southern US, draping over trees to generate an eerie peaked landscape and blanketing entire forests.  Or the icky zebra mussel that clings to manmade structures so well that it clogs industrial water intakes.  The Asian long-horned beetle that has munched through the forests of North America does not have many friends, even among animal lovers.  

Can something this cute really be an invasive species?
source: http://lol-rofl.com/wild-rabbit-habitat/

But what about the adorable bunny?  There is no Australian equivalent to the European bunny.  Bunnies introduced to Australia by Europeans have been ravaging the Aussie countryside for over a century.

Australians call this a "plague of rabbits"
Source: http://www.pir.sa.gov.au/biosecuritysa/nrm_biosecurity/pest_animal/pest_animal_programs/european_rabbits

When Europeans established penal colonies in Australia in 1788, they brought European culture, including an affinity for rabbit farming and sport.  Starting in 1859, the Acclimatisation Society encouraged the release of rabbits into the wild so that settlers could enjoy rabbit hunting (Crisp 2009, Kerr 2008) unaware that they had started one of the fastest colonization of any invasive species.  By 1900, the rabbits had almost spread across the entire continent.  By 1950, their population had grown to 600 million. Despite reductions in population due to disease, rabbits still outnumber humans 13:1 and have significantly impacted ecosystems throughout Australia (Crisp 2009, Kerr 2008, DEC NSW 2005).  Recent efforts to halt or reduce rabbit population growth have failed as the rabbits continues to grow in number (Zuckerman 2009.

Negative Impacts of Rabbits Invading Australia

Despite their cuteness, rabbits have devastated the native ecosystems of Australia through:
• overgrazing

• reduced plant biodiversity

• promotion of non-native plants

• suppression of trees and shrubs with resulting cascading ecosystem impacts

• increased competition with native herbivores

• increased prey for introduced cats and foxes (Cooke 2012)

• food shortage in Australia

• financial crises for Australian farmers  (Zukerman 2009)

The Causes

The spread of rabbits across Australia can be traced to failures in science, policy and management.

Scientific research provided several biological control agents that directly reduced the population (Cooke 2012).  However, experiments have not been well controlled, resulting in the accidental early release of a lethal virus into rabbit populations before experiments had been completed.  This early release prevented coordination of the subsequent dip in population with corresponding management decisions as well as the release of the disease at a suboptimal time in terms of rabbit life cycle (Kerr 2008).  Biological control is one of the more cost-effective ways of reducing populations, but even very lethal viruses will leave some survivors who are resistant to future infection (Zukermon 2009).  The best tactic is to time biological agent release with other factors and efforts.

Public policy has improved since the deliberate release of 24 rabbits by the Victorian Acclimatisation Society in 1859 so that settlers would feel more 'at home' (DEC NSW 2005).  By 1901, a special Royal Commission meeting decided on an aggressive rabbit-proof fencing project.  But recently, these fences have fallen out of favor. The Queensland Government disbanded the Board responsible for the last serviced rabbit proof fence in the country, stretching 555 km to protect 28,000 km of farm land (Crisp 2009).  Inconsistent policies have allowed rabbits time to surge back and thwart long-term management capacity.

Management failures are more difficult to pinpoint.  The failure of the rabbit-proof fencing project in 1900-1907 is most likely a failure of management since the effort had sufficient political will from the Royal Commission .  The Commission stated with urgency, "to ensure rapidity of construction, the contractor [is to] be bound to simultaneously start operations with one party working north from the railway line … another party working south from the railway line, a third party working north from Fitzgerald Inlet, and other parties from any other convenient starting points" (Crawford 2001?).  Unfortunately, by the time the fences were completed, the "rabbits had already moved into the areas being fenced off." (Zukerman 2009).  This appears to be a time when an adaptive approach would have helped so that the managers could make decisions on the spot while watching the expansion of rabbit populations.

 

The Aftermath

Today, populations are surging again and the efforts of science, policy and management must coordinate to address the problem (Williams et al. 1995).

From the scientific realm, a new biological agent would jumpstart population reduction.  Also, gaps in knowledge hinder effective rabbit population control, in particular, questions of how predators, diseases, and resource availability interact (Robley et al. 2004). 

Gosling and Mintzberg's five mindsets of a manager help to frame the management approach (2003).  In the reflective mindset, it is important to take time to understand the system, evaluate past failings, and be sure to ask the right question.  The analytic mindset helps to understand the circumstances under which widespread rabbit eradication is possible. Read et al. says it takes proper timing, sustained effort over time "significant long-term planning, resources, commitment and dedication" (2011, 52). The worldly mindset can identify the context that best lends itself to eradication, such as the optimum scale and the amount of resources needed for long-term impact.  The collaborative mindset keeps track of public opinion and involvement as well as political will.  The action mindset ensures that the project avoids "paralysis by analysis" (Sunstein 2002) and stays nimble (Meadows and Marshall 2001).

There is no central information agency with standards for population data and tracking (Zukermon 2009).

Political support is needed to provide long-term funding for both management and scientific research (Robley et al. 2004).

Conclusion

What is most needed to address rabbit populations in Australia is higher coordination between scientific discovery, legislative support, and management techniques reduce populations and keep them low.  A central repository of scientific knowledge coordination, management that follows the five mindsets and consistent political support would go a long way in addressing this issue.

References

Anonymous. 1917. Rabbits in Australia. Journal of Geography 16, 31. Retrieved from http://search.proquest.com/docview/1290516993?accountid=10267

Cooke, B.D. 2012. Rabbits: manageable environmental pests or participants in new Australian ecosystems? Wildlife Research 39 (April): 279-289.

Crawford, J.S. 2001? History of the State Vermin Barrier Fences. The State Barrier Fence of Western Australia: Centenery 1901-2001. Accessed December 6. URL: http://pandora.nla.gov.au/pan/43156/20040709-0000/agspsrv34.agric.wa.gov.au/programs/app/barrier/history/Crawford_Rcommission.htm

Crisp, R. 2009. Run Rabbit, Run Rabbit, Run, Run, Run. AQ: Australian Quarterly 81, 5 (September-October): 36-37

Department of Environment and Conservation New South Wales (DEC NSW). 2005. Rabbits fact sheet. Pest Management in NSW national parks (December). URL: http://www.environment.nsw.gov.au/resources/pestsweeds/factsheetRabbits.pdf

Gosling, J. and Mintzberg, H. 2003. The Five Minds of a Manager. Harvard Business Review (November): 54-63.

Kerr, P. 2008. Biocontrol of rabbits in Australia. Outlooks on Pest Management (August): 184-188.

Meadows, D., and Marshall, P. 2001. Dancing with systems. Whole Earth (winter): 58-63.

Read, J.L., Moseby K.E., Briffa, J. Kilpatrick, A.D., and Freeman, A. 2011. Eradication of rabbits from landscape scale exclosures: pipedream or possibility? Ecological Society of Australia 12, 1 (April): 46-53.

Robley, A., Reddiex, B., Arthur, T., Pech, R., and Forsyth, D. 2004. Interactions between feral cats, foxes, native carnivores and rabbits in Australia. Final report to the Department of Environment and Heritage, Department for Sustainability and Environment, Melbourne, Vic.

Sunstein, C.R. 2002-2003. The Paralyzing Principle. Regulation (Winter): 32-37.

Williams, K., Parer, I., Coman, B., Burley, J., and Braysher, M. 1995. Managing vertebrate pests: rabbits. Australian Government Publishing Service: Canberra.

Zukerman, W. 2009. Australia's Battle with the Bunny. ABC Science (8 April). URL: http://www.abc.net.au/science/articles/2009/04/08/2538860.htm