I was recently faxed through a summary of research findings on the impact of aerial baiting on spotted quoll populations. The report is now available at the NSW National Parks website here.
There seems to have been a collective sigh of relief that baiting with 1080 for wild dogs will now occur in some National Parks and that baiting will now be considered for other parks on a case-by-case basis.
Report findings included that:
Although some analyses are still outstanding, the available results from each of the three separate aerial baiting trials conducted by the DEC during the 2004-05 period, and from the work undertaken in Queensland during 2002-05, have demonstrated that mortality among known quoll populations is much lower than that predicted by previous non-toxic trials. However, quoll mortalities due to 1080 poisoning do occur, albeit rarely.
It appears that quolls eat toxic bait at highly variable rates. More importantly, most quolls consuming 1080 dog baits survive. The consistency of these results across sites indicates little difference in the response to aerial baiting between distant quoll populations. Moreover, the observed low mortality rates due to 1080 poisoning are apparently not caused by an adaptation of quoll populations to repeated exposure to aerial baiting, but also applies to quoll populations in areas that have not had a recent history of aerial baiting.
Reasons for the lower than expected mortality of quolls in the wild are uncertain. It may be that, of the animals that consume baits, most have a higher tolerance of 1080 than would otherwise be predicted on the basis of laboratory-based trials (ie. they have a higher resistance). It is also possible that quolls regurgitate baits.
During any aerial baiting program, individual animals of a range of native species may be killed by 1080 baits including spotted-tailed quolls, brush-tailed phascogales and several species of dunnart and antechinus, native rodents, potoroos, brushtail possums and many species of birds. The recent research has shown that population level impacts on the species of greatest concern, the spotted-tailed quoll, is unlikely. However, it is possible that mortality due to aerial baiting may have significant impacts on small populations of quolls already suppressed due to drought, habitat fragmentation, disease etc. In addition, there is no information on the sub-lethal effects of 1080 on native species e.g. fertility and birth defects. On the other hand, aerial baiting which suppresses local fox and dog populations may benefit quolls in the area. Hence, the potential impact of aerial baiting on non-target species has to be assessed on a case by case basis.
After discussing the results and other published information, the Steering Committee agreed that aerial baiting can now be considered as an additional control technique where appropriate. However, in order to maximise effectiveness and minimise selection for bait-shy dogs, the Committee encourages the use of an integrated approach that employs a range of techniques e.g. ground and aerial baiting, trapping, shooting, exclusion fencing.
I read on Friday that a penguin colony off the coast of south-western Victoria is struggling to survive because of wild dog and fox predation. The breeding colony on Middle Island has been reduced from nearly 300 penguins to 60 according to the ABC Online report. A team from Deakin University are apparenlty monitoring population numbers. While I am all for more monitoring, it would be perhaps useful if the scientist also did some baiting, perhaps with 1080, when they return to the island in October?