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| Foxes in Tasmania - A Grave Threat to Our WildlifeNews and information on fox sightings.
A fox takes an eastern barred bandicoot |
The European red fox (Vulpes vulpes) has a natural distribution across the continents of Europe, Asia and North America. In the southern hemisphere, the European red fox occurs only in Australia, where it was introduced by English settlers in Victoria in the 1850s for hunting. The fox was reported in NSW by 1893, in South Australia by 1901, in Queensland by 1907 and in Western Australia by 1912. Within 30 years of its release in southern Victoria, it was given the status of "agricultural pest" and has since inflicted enormous impacts on the native wildlife of Australia, being implicated in the extinction of many native animals. Indeed, Australia's appalling record of mammal extinctions in the last 200 years - the worst in the world - is in no small part due to the fox.
Unfortunately, such evidence as carcasses and scats confirmed by independent DNA testing indicates that there is probably a small population of foxes in Tasmania.
The fox represents the single most devastating threat to Tasmania's native mammals and birds. This island State is recognised as a national and international fauna haven due to the lack of foxes, but should the species become established here nearly all of Tasmania's native land animals would be at risk.
Indeed, 78 native vertebrate species would be at risk if the fox became established. Of these, 34 species have locally restricted ranges, 16 are suspected to be already declining in distribution and 12 species are threatened according to Commonwealth or State threatened species legislation. This list does not include invertebrate species, many of which would also be at risk of fox predation.
Threatened and high conservation significance species at risk would include: The Tasmanian pademelon and Tasmanian bettong, both of which thrive in Tasmania, are now extinct on the mainland because of the fox. The mainland eastern barred bandicoot has been reduced to a mere 200 surviving individuals because of the fox. The young of unique species such as the Tasmanian devil, spotted tail quoll that are left unattended in dens are highly vulnerable to fox predation.
More widespread species like ducks, shorebirds, ground nesting birds, blue tongue lizards, mountain dragons, skinks and frogs are all highly at risk. Even animals such as the little penguin and platypus are at risk. Additionally, foxes are carriers of disease and spread environmental weeds.
A lamb attacked by a fox |
Domestic poultry, sheep and lambs are targeted by foxes. Foxes can also carry diseases which impact upon both native wildlife and domestic stock. They are known carriers of distemper, parvovirus, canine hepatitis, heart worm, hydatids and sarcoptic mange. Indeed, it is believed that the individual fox which escaped from a container ship in Burnie in May 1998 had a 12% chance of carrying heart worm.
The economic losses of livestock from fox attacks could equate to as much as $34.5 million per annum in Tasmania’s sheep industry alone (wool and slaughter).
In Europe, the fox is the main carrier of rabies. Should rabies ever be introduced into Australia, foxes would likely be the main agent of its spread.
The European Red Fox is recognised nationally as the single most devastating introduced pest and threat to Australia's native land animals. It has been listed as a National Threat on the Commonwealth Endangered Species Protection Act 1992.
A national research and management effort is underway to investigate and trial biological and other forms of eradication. To date, there is no evidence that control measures have met with success in limiting the distribution or abundance of the fox. Introduced to mainland Australia in the 1850s, it is now widespread across every State except the tropical far north and Tasmania.
Australia's wildlife has not evolved in the presence of foxes, and therefore lacks adequate adaptations to cope with the predatory prowess of the fox. In Victoria, for example, the fox has established itself in all terrestrial environments from inner urban areas to alpine heaths, rainforests to coastal heaths and mallee. It is known to have caused the extinction of six mammals and is currently causing the near extinction of the: - Eastern barred bandicoot
- Long footed potoroo
- Broad toothed rat
- New Holland mouse
- Mountain pygmy possum
- Brushtailed rock wallaby
- Broad-shelled tortoise
- Malleefowl
- Hooded plover
- Little tern.
Foxes are reproductively receptive once per year (seasonally mono-estrous) and are stimulated to breed by changing day-length and resource availability. Gestation is 51 to 53 days with most cubs being born between August and September. Mean litter size is 4 with up to 10 being possible. Cubs are weaned by about one month and are sexually mature by 10 months. They usually have well defined home ranges with spatially stable borders. Ranges vary in size depending on habitat and have been recorded at around 30 ha in urban areas and up to 1,600 ha in arctic environments. In general, foxes are active from dusk to dawn and rarely travel more than 10 km per day within their home range. Dispersal is common in sub-adult males.
In Victoria, foxes generally pair up in early winter and mate in mid to late winter. They usually hide in shelters during the day and evening. Foxes around the Port of Melbourne (Victoria dock area) shelter in thick weeds such as blackberries and remain totally quiet until after midnight. Their activity increases gradually after midnight to reach a peak in activity from 1 am to 3 am. Data on these urban foxes suggest that first and second year animals do not generally disperse further than 1 to 2 km from their natal area.
The population estimate of the fox in Victoria is 1 to 2 million (widespread) and in NSW is 3 to 6 million (widespread), with a common density of 4 to 8 animals per square kilometre. A single fox is estimated to eat about 400 gm of food each night (equivalent to one bandicoot). One million foxes potentially eat 400 tonnes of food per night or 146,000 tonnes of food per year. In some cases this has been estimated to consist of one third native species, one third domestic stock, and one third feral pests such as rabbits, mice and rats.
The fox on mainland Australia has few natural predators except for humans, dingos and eagles. Tasmania, however, has a range of native carnivores (e.g. Tasmanian devil) which could potentially predate fox cubs. Mortality is thought to be due to seasonal factors such as drought, mange and distemper.
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