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Beyond the Bale : Apr 07 - May 07
By Kellie Penfold The chairman of a newly formed rabbit management advisory group, Broken Hill woolgrower David Lord, believes the removal of rabbits from the local landscape has resulted in massive biodiversity gains and lifts in flock productivity. David manages the family woolgrowing business on 'Thackaringa', 40 kilometres west of Broken Hill, and he says that before an extensive rabbit control program in the early 2000s, there were 28,000 rabbit warrens on the property. "In November 1995, rabbit haemorrhagic disease (RHD) swept through 'Thackaringa', killing an estimated 750,000 rabbits, which is roughly equivalent to 75,000 DSE (dry sheep equivalent) of sheep," he says. "We took advantage of the rare opportunity offered to us by RHD, and the availability of some funding under the Natural Heritage Trust, and began a big effort in 2002 to rip the remaining 22,000 warrens, having started ripping in 1988." By March 2003, David had completed ripping all 28,000 warrens on the property. He says the problem is not unique to his property; anyone with a similar soil type will have similar warren densities. "I'd encourage anyone who feels they can manage it to rip their warrens -- it is probably a better business investment than buying land at inflated prices." David believes that removing the rabbits has provided the single biggest gain in feed base on his country. "Coupled with genetics, what goes into their mouths is one of the most important elements in improving flock productivity," he says. "Rabbits select the best food -- the fresh new shoots and plants -- and eat it before you even see it. Production gains don't necessarily come from increasing the number in the flock. Some of the greatest gains come from increases in wool cut, lambing percentages and body weight. Post-RHD and myxomatosis, rabbits at their very-much-reduced numbers are insidious -- unseen but still dangerous -- and it's difficult for some people to understand just what impact they have." The district has endured 15 continuous years of extreme rainfall deficit and David believes that if rabbits had remained at an elevated level, he might not have been able to retain a nucleus flock of breeding ewes. "We have not yet seen the true gains of RHD because we haven't had a good season since its release. But while it is very hard to claim production gains in such a short space of time, we are fairly confident they are there, judging by the condition of the sheep in what can only be described as horrendous seasons. "One of the amazing things that has been obser ved on 'Thackaringa' since RHD swept through, and the ripping was undertaken, is how little rain is needed to germinate and support native plants. My father John talks about 1949, just before the release of myxomatosis, when over three nights at one water point he caught 20,000 pairs of rabbits -- that's roughly the equivalent of 4000 DSE." David is one of two woolgrower representatives on the recently formed rabbit management advisory group, which will work with AWI, Meat and Livestock Australia (MLA) and the Invasive Animals Cooperative Research Centre (CRC) (see opposite). Jonathon Tischler from Skipton, Victoria is the other woolgrower. Ripping the warrens on 'Thackaringa' was a slow and exacting process. Every warren location was logged by GPS and stored on computer before the arrival of the bulldozer in the paddock. There was one warren for every 0.47 hectares of land in the major soil type on 'Thackaringa'. Work was only carried out in the hot, dry summer months when the rabbits were deep underground. David would lead Operation rabbit removal Ripping rabbit warrens on his property near Broken Hill has provided not only biodiversity gains but the single biggest boost to the feed base, says David Lord 12 INVASIVE ANIMALS BEYOND THE BALE David Lord, of 'Thackaringa', Broken Hill: once there was one rabbit warren to every 0.47 hectares of his property. PHOTOS: KELLIE PENFOLD
Jun 07 - Jul 07
Feb 07 - Mar 07 Supplement