USQ submission to NSW inquiry shows no detrimental impact of cluster fences

The chief executive of the Kangaroo Industry Association of Australia, Dennis King has said that scientific studies were needed to determine the animal welfare outcomes caused by exclusion fences.

His members believed the breeding systems of kangaroos had been changed by the erection of thousands of kilometres of fencing through Queensland's rangelands.

He said that as far as he was aware, no-one was looking into the outcomes of cluster fencing.

However, information sourced from long-term experimental research programs conducted in western Queensland, New South Wales and South Australia were presented in April by University of Southern Queensland senior research fellow Benjamin Allen to a NSW government inquiry into the health and wellbeing of kangaroos and other macropods in NSW.

His information comes from sites inside and outside the first modern exclusion fences, the Morven and Tambo clusters, completed in 2015.

Dr Allen told the inquiry they had been monitoring kangaroo and other wildlife populations inside and outside these two fences since 2013, "enabling an experimental assessment of fauna populations before, during and after fence construction".

"Kangaroo population abundance is, on average, three to four times higher inside these fences than outside," his submission read.

"Population trends have naturally fluctuated over time and have declined marginally both inside and outside the fences due to the recent widespread drought.

"However, population trends at each site have not diverged and these fluctuations were similar inside and outside the fences, demonstrating that exclusion fencing has not caused any observable declines of kangaroos over this period."

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He went on to say that claims that exclusion fences were detrimental to kangaroo health and wellbeing were not borne out by the research, for several reasons.

As well as higher populations inside fences in general being the best measure of their health and wellbeing, Dr Allen said the reduction of wild dog predation had been widely shown to result in kangaroo population increases.

In addition, the removal of wild dogs meant hydatid tapeworms, which can cause a variety of serious sub-lethal and lethal clinical effects, were less likely to be transmitted by wild dogs to kangaroos.

The hydatids are maintained within kangaroo populations by the presence of wild dogs, so removing them breaks the life cycle, Dr Allen said.

"Cluster fences thereby indirectly benefit kangaroo health and wellbeing through multiple pathways, which ultimately enable kangaroo populations to increase and thrive at levels three to four times higher than background levels."

His submission also touched on the effects of exclusion fencing on kangaroo habitats.

Remotely-sensed and ground-truthed vegetation monitoring inside and outside the Morven and Tambo cluster fences showed that food and habitat resources inside the fences were not being depleted by livestock, kangaroos and other grazing animals.

That suggested that since fencing, average total grazing pressure from sheep, cattle, goats, and kangaroos both inside and outside fences is likely to have been similar, and that rainfall variability dominates the ground cover signal.

"Put simply, available kangaroo habitat and food resources are the same inside and outside agricultural exclusion fences," he said, adding that similar data from additional cluster fences was available on request.

He acknowledged the potential for some negative effects to individuals or to populations at smaller spatial scales, and said there were anecdotal reports of unauthorised large-scale culls of kangaroos within fences, resulting in population declines of up to 95 per cent.

"Some of the means described to achieve these culls certainly sound very concerning," he said. "Some individual kangaroos will also undoubtedly become entangled in fences and die."

Although fences inhibit long distance dispersal through fenced regions such as western Queensland, Dr Allen said the available data doesn't suggest that it is so bad that it compromises the health or abundance of kangaroo populations at larger scales.

"Two things can be true at the same time: there may well be some negative effects of fences on kangaroos in some contexts and reports of such negative effects are not unexpected, but there is also no evidence that the health and abundance of kangaroos is compromised at the population or regional level.

"At the large scales relevant to kangaroo conservation and management, kangaroo populations are not harmed by fences, but are rather benefited by them in a variety of ways."

There are now over 100 cluster fences covering more than 65,000 square kilometres in Queensland alone.

Dr Allen said he was likely to continue to monitor the Morven and Tambo fences until at least 2025.

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