In Tasmania Feral Foxes Take Over
Tasmanian Devils Decline And Introduced Foxes Create Havoc
The loss of Tasmanian Devils to tumours is allowing non-native red foxes to fill a niche on the island, with potential loss of local wildlife.
Devil Facial Tumour Disease (DFTD) has reduced the population of Tasmanian Devils (Sarcophilus harrisii) by nearly 80%. And in the vacuum left by this native predator/scavenger species, non-native European red fox (Vulpes vulpes) populations are taking advantage. As fox numbers grow so will the losses of small mammals, ground nesting birds and reptiles, all victims of the foxes’ eclectic dietary tastes. The ecosystem of Tasmania may fall out of balance.
Red Fox Introduction
Starting in the late 1990s evidence began to mount that European red foxes were present on the island. Data produced by the DPIW (Department of Primary Industries and Water) shows hard evidence of foxes on the island from 2002 onward. The loss of 50,000 to 70,000 Tasmanian Devils to DFTD at about the same time means there is more food and less competition for the foxes. In fact, the first areas colonised by the foxes were the areas hardest hit by DFTD. As is often the case with a non-native species, there is a lack of natural controls on the fox in Australia.
The Tasmanian ecosystem has long been a stronghold for endemic species, in contrast to the mainland where 17 species have been lost and a number of others have become critically endangered within the last 200 years. On the island, only the Thylacine or Tasmanian tiger has gone extinct in that time period. Now fox predation threatens that record.
Endemic Species Threatened
Bandicoots, eastern quoll, long nosed potoroo and Tasmanian bettong.
Small rodents
Long tailed mice , velvet furred mice and New Holland mice,
Reptiles
Green and gold bell frog, tussock skink and glossy grass skink
Shorebirds and ground nesting birds
Hooded plover, little tern, fairy tern, ground parrot, ground thrush, painted button quail, great crested grebe and night parrot
It was originally thought that only small mammals would be taken by fox but medium sized species have been regularly predated as well. Nest predation, with loss of eggs and chicks, is the biggest threat to the shorebirds. However, adults are also lost to foxes. And if that weren't enough threat to the local native species, feral cat populations are also booming in the wake of the Tasmanian Devil losses.
Some local native species were predated on by Tasmanian devils, but the devils are also specialist scavengers utilizing every part of a carcass except the largest of bones. Large mammal carcasses and even dead fish on the beach are fair game for them, which means they take fewer live animals and keep the environment clean. Most importantly, the Tasmanian devil belongs in this environment. The European red fox doesn't.
Other Sources:
- Foxes on the Move, The Sunday Tasmanian, March 11, 2007
- National Geographic News, Eco-Terrorism blamed for Tasmania fox release
