Emerald Messenger

“And he ran them single-handed till their sides were
white with foam.
He followed like a bloodhound on their track,
Till they halted cowed and beaten, then he turned their
heads for home,
And alone and unassisted brought them back.
But his hardy mountain pony he could scarcely raise a trot,
He was blood from hip to shoulder from the spur;
But his pluck was still undaunted, and his courage fiery hot,
For never yet was mountain horse a cur.”
– Extract: The Man from Snowy River,
source – Australian Poetry Library, Andrew Barton Paterson.

Introduced feral-horses (Equus caballus) have had a dramatic negative impact on fragile alpine environments in Australia. Trampling and grazing has reduced vegetation cover and increased soil compaction, erosion, siltation and stream bank damage resulting in reduced water quality and widespread water catchment damage. Endangered ecological communities such as wetlands, sphagnum bogs and fens are critical habitat for several endemic species such as the critically endangered Corroborree frog (Pseudophryne corroborree), as they provide critical breeding habitat.
Although the decline in Corroborree frog numbers is primarily caused by a disease, the indirect effects of feral-horse trampling on the vegetation (and directly onto the frogs) is severely hampering any conservation efforts to save the species. Many advocates for the ‘Brumby’ have an overly-romanticised view of feral horses believing that they are an Australian native animal (which they are not) and as such have a right to be there. There are over 10,000 feral-horses roaming all over the Victorian and New South Wales Alpine region with numbers increasing most dramatically in the past 15 years. With only 17% of Victoria set aside for National Parks surely these feral-horses do not belong in our most fragile natural environments.
Fossil records indicate that the history of cats goes back 33 million years when the European Cave Lion ranged extensively throughout Europe, Asia and into Alaska. From Canada to Mexico the North American Cave Lion roamed and across Eurasia and in the America’s sabre-toothed cats thrived.
Lions and cats have been heavily persecuted and hunted throughout history with most living species either endangered, critically endangered or functionally extinct. For example, the Balkan Lynx has such a small population that its demise is inevitable. In contrast to all other members of the family, the domestic cat now ranges across most of the global terrestrial landscape, expedited by humans.
The domestic cat is singlehandedly responsible for the global extinction of at least 63 species. In Australia, both feral cats and free-roaming pet cats kill over one million birds per day and are in part responsible for the loss of 20 mammal species including the lesser bilby and the desert bandicoot.
More than a dozen species of native reptiles are threatened with extinction in the near future caused by the global estimate of 600 million domestic cats. In Australia an urban cat kills up to 30-50 times more animals per square kilometre than feral cats in the bush. For example, an ordinary domestic cat can kill 186 animals a year, while feral cats in a natural environment on average kill 40 reptiles, 38 birds and 32 mammals annually.
Predator-prey relationships are heavily influenced by habitat structure and quality. After bushfires cats have been shown to quickly move into the homogenised landscape and exploit it for small mammals and other prey that have difficulty hiding and are forced to forage in the open.
The incidence of bushfires and increased grazing pressures have meant that small native species are now more vulnerable than ever to predation by roaming cats. Coupled with the persecution of the dingo (whose role as a trophic regulator could help keep feral cat numbers in check) and changed fire regimes have paved the way for the success of the feral cat in the wild.
What can we do to help biodiversity? Support the removal of feral horses in the alpine, support conservation efforts that are helping to restore alpine ecosystems, practice responsible pet ownership (with your cat) and support the conservation of our native dingo that helps to keep feral animal numbers in check.
Final year student Environmental Science – Charles Sturt University

Categories: July 2020