Marc Widmer successfully defends WA from European wasp. and the environment. Susan Campbell. Supporting your success

Transcription

1 Marc Widmer successfully defends WA Rabbits: from European wasp destructive attack. pests of agriculture and the environment. Supporting your success Susan Campbell

2 70 years A brief history 1859 successful introduction of 24 rabbits in Victoria ~1930 colonisation of 2/3 rd country by ~10 billion rabbits

3

4 70 years A brief history 1859 successful introduction of 24 rabbits in Victoria ~1930 colonisation of 2/3 rd country by ~10 billion rabbits 1950 release of myoxa virus = 99.8% reduction 1990 population recovery to ~600 million rabbits 1995/96 release of rabbit haemorrhagic disease virus (RHDV) Average 67% reduction in arid areas Average 27% reduction in higher rainfall areas (highly variable) ~2010 rabbit numbers nationally trending upwards

5 Inevitable recovery? Why do rabbits always bounce back? Some rabbits survive exposure to virus: Individual variation Genetic immunity in populations evolves over time RHDV specific immunity: Maternal antibodies up to ~6-8weeks (variable) Innate resistance in very young rabbits Benign virus

6 Breed like rabbits Why do rabbits always bounce back? 2 years 2 years , 000! Sexually mature at 3-4 months Gestation lasts ~31 days 2-12 kittens per litter 4-7 litters per year Female can mate within hours of giving birth One doe can produce offspring per season Rabbits success has been aided by the use of warrens which provide shelter in hot / dry habitats.

7 Rabbit impacts Rabbits are Australia s most destructive agriculture pest. Competition with, and land degradation from, rabbits threatens over 300 native plant and animal species. Environmental Even very low densities of rabbits (<1 rabbit per hectare) can prevent the regeneration of perennial plant species 304 listed native species threatened by rabbits Rabbits are food for feral predators Agricultural Rabbits are Australia s most costly agricultural pest, causing over $200 million in damage per year Social Rabbits threaten places, plants and animals that people value

8 70 years A brief history 1859 successful introduction of 24 rabbits in Victoria ~1930 colonisation of 2/3 rd country by ~10 billion rabbits 1950 release of myoxa virus = 99.8% reduction 1990 population recovery to ~600 million rabbits 1995/96 release of rabbit haemorrhagic disease virus (RHDV) Average 67% reduction in arid areas Average 27% reduction in higher rainfall areas (highly variable) ~2010 rabbit numbers nationally trending upwards 2017 RHDV Boost

9 Rabbit abundance index The need for new biocontrol 140 Rabbit numbers (solid blue line) continue to recover post biocontrol 120 Myxomatosis Benefit from myxomatosis RHD 20 Rabbit impact threshold Benefit from RHD RHD-Boost RHD-Accelerator Bioprospecting 0

10 Selecting a new strain of RHDV RHDV1-K5: a naturally occurring variant from Korea 37 naturally occurring strains imported and tested. RHDV1-K5 Overcomes antibodies to RCV-A1 (benign strain) The existing commercial vaccine is effective against RHDV1 Requires 30 times less virus compared to original strain to infect wild rabbits RHDV1-K5 infection results in increased (and faster, ~24-36hrs) mortality RHDV suspension is a Restricted Chemical Product Authorisation training required in WA. RHDV1 K5 is now available as a commercial product Contact DAFWA for details on training and access.

11 Directions for use RHDV1-K5: Directions of use May be administered to susceptible rabbits either by direct injection or by means of infected carrot or oat feed. RHDV1-K5 will not infect any other animal. Animals that may consume a rabbit that is sick or deceased from RHDV1-K5 will not be affected by the virus.

12 Spread RHDV1-K5: Infection pathways Bush and blow flies are known vectors for RHD virus and will spread virus over large distances, assisted by prevailing wind streams. Flies deposit virus as fly-spots on pasture, which is then consumed by rabbits. Flies can also spread the virus directly to rabbits by landing on individuals. Virus can be spread easily by direct contact between rabbits Biting insects such as mosquitoes and fleas can also spread infection.

13 Timing RHDV1-K5: When do outbreaks occur? Outbreaks are more likely when vector (fly / flea / mosquito) activity is high. Avoid applying when there is a high proportion of rabbits <12weeks old or pregnant does. Best practice time for deliberate release is late Spring / Autumn (adequate vector activity, lower proportion of kittens present and lower availability of alternate food sources) Supporting your success

14 The national release of RHDV1 K5 RHDV1 K5 released at close to 600 sites in March community managed release sites 104 (<20%) supplied pre-release count data 52 (<10%) supplied post-release count data Nationally 42% reduction in observed rabbit numbers Most states ~36% reduction in observed rabbit numbers

15 West Australian release sites Out of 163 initial expressions of interest, 106 community releases in WA

16 RHDV2 in Australia In May 2015, RHDV2 virus detected in wild rabbits in Canberra, and has since spread across the majority of the country. RHDV2 is present in Europe, it is not known how it arrived into Australia. RHDV2 causes the same mode of death as RHDV1, however they are two separate viruses. The currently available vaccine is not fully protective against RHDV2. RHDV rabbit carcass: Brian Lukin, NSW DPI

17 Control Maximising benefits INTEGRATED CONTROL Full benefits of biological control are only achieved where poisoning, warren ripping and fumigation are used to remove remnant rabbits and their harbour (warrens) Follow up with conventional control A significant opportunity to really supress rabbit numbers was missed after the release of the original RHDV1-czech strain due to a lack of follow up control. To promote long-term area freedom from rabbits, conventional control including baiting, harbour destruction (including warren ripping) and other methods are required immediately after a successful outbreak of RHDV to mop up survivors and remove the critical resource (warrens / harbour).

18 Conventional control options Baiting Warren ripping Fumigation Shooting Exclusion fencing

19 Baiting Baiting permit required (contact DAFWA) Two types of toxin available for rabbit control (Sodium fluroacetate) - Pindone WORK TOGETHER Can achieve high control rate Cover large areas Selective - Bait stations Non Targets-1080 Tolerance Choice of toxin to suit situation Secondary poisoning Pindone

20 Integrated Pest Management Protection of fauna Rabbits provide a food source for foxes, feral cats, dingoes / wild dogs and birds of prey. Decline of rabbit numbers from any cause may result in increased predation on critical populations of vulnerable or endangered fauna, at least in the short term. Be aware of populations of native animals before undertaking rabbit control and seek advice from DPaW. Complimentary predator control measures should be implemented if necessary. Evidence shows that in the long term, fewer rabbits present in an area tends to result in fewer predators.

21 Thank you Visit agric.wa.gov.au Important disclaimer The Chief Executive Officer of the Department of Agriculture and Food and the State of Western Australia accept no liability whatsoever by reason of negligence or otherwise arising from the use or release of this information or any part of it. Copyright Western Australian Agriculture Authority, 2016 Supporting your success