Solving rabbit the rabbit biosecurity and biodiversity
Rabbits were introduced in Australia in 1859 and spread rapidly and widely to become one of Australia’s most destructive pests. Within 70 years they spread to 70 per cent of Australia’s land mass, the fastest known invasion by a mammal anywhere in the world. They compete with livestock and native animals for food, affect tree plantings, and reduce ground water absorption. Less than two rabbits per hectare are sufficient to prevent the regeneration of native vegetation. Competition and land degradation by rabbits is listed as a key threatening process under the Environmental Protection & Biodiversity Conservation Act, and a Threat Abatement Plan is in place. Economic impacts include loss of agricultural productivity, control costs, land values, and national park management costs. Losses caused by rabbits to agriculture and horticulture in Australia are estimated to be about $239 million per year, not including environmental and social impacts.
Releasing the myxoma virus for biological control of rabbits
CSIRO’s predecessor (CSIR), carried out initial trials that ultimately resulted in the successful release of the myxoma virus for the biological control of rabbits in 1950. This resulted in a dramatic reduction of Australia’s rabbit population. It was the world’s first successful biological control program of a mammalian pest. However, by the late 1950s, host-pathogen co-evolution led to development of genetic resistance in rabbits and the appearance of less virulent virus strains, and rabbit numbers increased again. In response to this challenge, CSIRO began a project to investigate the possibility of Rabbit Haemorrhagic Disease Virus (RHDV) as a potential biocontrol in 1989. The virus was brought to CSIRO at the Australian Animal Health Laboratory in 1991; and was assessed extensively for its suitability as Australia’s second rabbit biocontrol agent.
Improved profitability of agricultural industries
The release of this virus began in late 1996. RHDV reduced rabbit numbers to very low levels, with the greatest impacts observed in arid zones, and lesser impact seen in high rainfall areas. A review of the economic benefits of the biological control of rabbits in Australia from 1950–2011 conservatively estimated that biological control of rabbits produced a benefit of A$70 billion (2011 A$ terms) for agricultural industries over the last 60 years (Cooke et al. 2013).
Looking at a range of impacts, our conservative estimates suggest that the real research and development expenditure of $6.5 million per year will lead to (“CSIRO in context” not including extension and implementation costs):
- Total benefits (measured as avoided loss in agricultural production and savings in control costs, in real, present value terms) between $9.5 million and $230.6 million over the next 10 years, depending on the assumptions made;
- A benefit cost ratio between 2.5:1 and 36.3:1.