Charles Sturt University research shows that feral animals, such as cattle and water buffalo, are damaging national parks and conservation areas in northern Australia.
It is from the remotest parts of the NT that a CSU PhD candidate has sought inspiration for research that could make an impact on the longevity of the land in the Top End.
Helenna Mihailou moved from Melbourne to Limmen National Park in the NT where she completed her PhD.
Her research is intended to inform policies to protect the native flora and fauna in national parks and conservation areas.
It was while living at Limmen National Park that she noticed the negative impacts of feral ungulates (also known as hooved mammals) on savanna waterholes.
Ungulates are not native to Australia, and therefore native ecosystems are sensitive to damage from grazing and trampling by these large animals.
In hot climates, ungulates can drink up to 10 per cent of their body weight in water per day, which concentrates their impacts around water points.
For her research, Ms Mihailou fenced 10 waterholes in Limmen National Park to exclude feral ungulates, mostly cattle and water buffalo.
Through surveys of the 10 fenced and another 10 unfenced control waterholes, as well as imagery collected using automated wildlife cameras, Ms Mihailou made several significant conclusions.
“I found that there was significantly more bare ground around the edge of waterholes accessible to ungulates,” she said.
“Bird diversity was significantly lower as the dry season progressed at waterholes accessible to ungulates, compared to fenced waterholes.
“This shows that the use of small-scale fences can provide important refuge areas for native bird species during periods of water scarcity.”
Ms Mihailou found that macropods, dingoes and feral ungulates visited waterholes more during the drought, but that cattle visitation increased the most dramatically, visiting about three times more often and spending six times longer at the waterholes.
This behaviour by cattle may increase competition with native species for access to important resources available at waterholes during drought years.
“Overall, this research indicates that even at low densities, feral ungulates have significant negative impacts on native flora and fauna communities around savanna waterholes in northern Australia,” Ms Mihailou said.
Associate Professor in Ecology/Ornithology Melanie Massaro supervised Ms Mihailou during her research. Prof Massaro intends to further research the impacts of feral ungulates in the NT.
Comparisons have been made to feral cattle being as big of a problem in the NT as brumbies are in NSW and Victoria.
But even with proof of the damage caused by ungulates, Ms Mihailou said the issue was more complicated due to the role of extensive pastoralism in northern Australia.
“Pastoralism is a big industry in northern Australia,” she said.
“Due to the sheer size of pastoral properties, domestic cattle often stray off pastoral properties into national parks, protected areas and conservation reserves.
“This is a real concern for the management of national parks and the protection of threatened native species in these parks.”
Ms Mihailou said land managers of national parks and other protected areas were largely powerless to cull feral cattle because those cattle, even those that have been feral for generations, are considered the property of whoever owned the branded animal from which their lineage began.
However, ownership of such feral, untagged animals cannot be determined without expensive DNA testing, creating a no-win situation for land managers.
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