Ecologist Ray Mjadwesch has sent the following letter to the Canberra Times (unpublished to date) in response to Hugh Tyndale-Biscoe’s article concerning the Open Letter:
Writers for kangaroo shooting are far removed from science. Hugh Tyndale-Biscoe’s opinion piece to the Canberra Times is not based on science, or reality.
He has shown ignorance of facts with regard to translocation. In the 1970s and 1980s over 2000 Eastern Grey Kangaroos were translocated to save the species in the island state, after habitat loss and shooting had reduced the population to only 10% of their numbers at settlement (Tanner & Hocking 2000). Talking about unsuccessful possum translocation is simply not relevant and is even misleading, when he could have talked about successful kangaroo translocation instead.
His “20 joeys per doe” assumes that they can have their first joey while still in the pouch, when in fact they generally don’t have a joey until they are 3 years old. Equally nonsensical is suggesting that kangaroos continue breeding until their death, if they survive to 20 years of age. Books on the topic (eg Dawson 2012) tell us they stop breeding from about 12 years of age (and none breed beyond 15 years of age), and about 8 joeys in a life time is a good effort (if they survive that long).
Mr Tyndale-Biscoe suggestion of 0% juvenile mortality reveals a lack of reading of the literature on joey (or any other juvenile wildlife) mortality. Research under “normal” (non-drought) conditions has found 73% mortality in their first year (Arnold 1991), and studies in the ACT found 50% of joeys are killed by foxes at the emergent stage (Banks 2000). This is an incredible position for someone purporting to be a marsupial biologist to take.
Mr Tyndale-Biscoe’s reflection on how peaceful it must be to be shot to death is an absurdity far beyond insensitive or the realms of decency, given recent events. It also shows a lack of knowledge about the realities of death by shooting, and a complete lack of experience of mis-shot kangaroos with noses blown off, shattered faces or major body trauma.
The fact remains that the ACT kangaroo shooting program does not have any scientific basis or justification.
There were no baselines established prior to commencement of the shooting program (no baselines = non science); kangaroo survey methodologies and timing changes from year to year (methods not replicated = non science); assumptions of high population growth rates for the species are not correct (populations grow slowly, while the architect of the program thinks populations can grow at rates “much more than 73% per annum” (analysis based on incorrect assumptions = non science); and positive interactions between kangaroos and their environment are ignored by ACT researchers, while supposed negative interactions are over-stated (bias = non science). The list goes on.
There is no causal link between kangaroo density / grazing and biodiversity – much less is there any scientific evidence of negative impacts of kangaroos on other organisms in the environment, and Dr Fletcher admitted such statements by Mr Inglesias and Mr Rattenbury were “PR” in his evidence to the ACAT hearing in 2013. Yet since then he seems to be doing everything in his power to prove such a link.
In his evidence to the 2014 hearing Dr Fletcher described kangaroos, a native species coevolved as part of Australian ecosystems, as a “major threat to biodiversity”. This bizarre statement infers that thousands of threatened species researchers and managers across Australia who do not consider kangaroos a “major threat” must be incompetent.
The major threats to threatened species in the ACT remains habitat loss, and includes additional well-recognised factors such as fox and cat predation and weed invasion, for example. ACT’s kangaroo exclusion fencing has killed over 100 reptiles; the CSIRO have collected (killed) literally dozens of “specimens” of Grassland Earless Dragon and Striped Legless Lizards; slashing kills Perunga Grasshoppers, Grassland Earless Dragons and Golden Sun-moths (which need kangaroo grazing to ensure open patched soil); kangaroos are shot without evidence they impact on any of these species but because they reduce biomass, yet hard-hooved stock and fire are brought in to reduce biomass to well below any levels caused by kangaroo grazing.
Mr Tyndale-Biscoe’s opinion piece is not science; it is nonsense that seems to have been trotted out by the Canberra Times in what looks like an embarrassing attempt to brainwash the public that the program has merit. As a scientist and a threatened species management specialist, I assure you it does not.
Ray Mjadwesch Responds