Rabbits, foxes & feral dogs, are a significant cause of lost productivity for Australian woolgrowers and affect biodiversity on farms. AWI continues to proactively develop new methods for controlling these pests. Recent research delivered assessments of the current populations and the best means of control into the future.

Rabbits

Rabbits remain the most costly agricultural and environmental pest in Australia. AWI has invested in projects to gain an understanding of the status of RHD and the impact of rabbits on biodiversity and lost productivity.

From the initial control methods of the 1950s through to the introduction of RHD in the mid-nineties, the control of rabbits has been a significant, industry-wide issue.

Rabbits remain the most costly agricultural and environmental pest in Australia.

Rabbit Haemorrhagic Disease (RHD) or Calici Virus, released in 1995 has provided significant economic and environmental gains through lower rabbit numbers and reduced grazing pressure in many areas. However, in areas where RHD has had little impact, rabbits still reduce wool and meat production.

Recent observations by landholders in some regions have reported increased rabbit populations although state agencies report no clear trends, up or down, in rabbit numbers. This might indicate rabbits have not yet developed resistance to RHD. Until now, there has been no attempt to determine if resistance to RHD is developing.

The AWI supported rabbits program, covered four projects :

1.Understand the effectiveness of RHD in reducing rabbit population since its release.
Modelling found that RHD effectiveness varies between temperate & semi arid environments. RHDv occurs mostly in summer at Bacchus Marsh (temperate), yet has a stronger impact, normally during the winter, in reducing rabbit abundance at Gum Creek (semi arid). The results suggest that there is unlikely to be a common model to describe the impact of RHD in all environments.

It was concluded established methods of control, poisoning, warren ripping and fumigation, provide the best option for value adding to RHDv.

2.Determine whether genetic resistance to RHD is emerging in the rabbit population.  
Limited experimental research has shown that rabbits have not developed such high resistance that they can withstand a high virus challenge but resistance to infection is demonstrable in some populations at a lower dose. Resistance appears to be developing most rapidly in areas where RHDv impact has been highest (sheep wheat zone).

3.Estimate the economic impact of rabbits at their current population levels.

This project developed an economic decision model which can be used as a research application or modified to regional needs, to recommend the most effective means of treating rabbits and which vegetation assets should have highest priority in terms of giving the best returns on investment.

4.Estimate the impact of rabbits on plant diversity in the pastoral and higher rainfall zones.
Results show that it takes only 1 rabbit/ha to significantly reduce the capacity for many native plant species to regenerate. It is hypothesised that losses to roadside biodiversity may well occur before rabbits reach levels where they cause noticeable economic damage to agricultural land.

A rapid survey available for download will assist producers & conservation managers determine whether rabbit control is required to protect native vegetation.

This work will guide future rabbit research and development towards advancing sustainable options for control and management of rabbits.

Foxes and feral dogs

The most significant and harmful predators of sheep, foxes and feral dogs, pose an ongoing threat to productivity.

Feral dogs and foxes maim and kill sheep and are responsible for a $33 million loss to woolgrowers every year.

In some areas of Queensland and Western Australia, and along the Great Dividing Range in NSW/Victoria, sheep production is being significantly impacted because of the ongoing damage inflicted by feral dogs.

Dogs and foxes are controlled primarily by baiting with sodium fluoroacetate (known as 1080). 1080 has come under pressure from groups concerned that it does not provide a humane death. AWI has argued strongly for the continued availability of 1080 for predator control because of the lack of suitable alternatives.

As a result, AWI initiated two major projects in feral dog and fox control:

Development of a new canid (dog and fox) toxin

This is a major investment with the Invasive Animals Cooperative Research Centre. The toxin under investigation causes a rapid and humane death and is highly specific to canids.

Development FeralMone, with Pestat Pty Ltd

FeralMone contains abbreviated synthetic fermented egg, a powerful attractant for dogs and foxes which has performed very well in field trials. FeralMone was launched in 2005.