The new finding, published this week in the prestigious journal Proceedings of the Royal Society B, is the first confirmation of what has been a long-held hypothesis among scientists.
It also highlights the heavy continuing impact of these predators long after their introduction and that Australia's fauna has been among the hardest hit in the world.
Experts believe that introduced "alien" predators are more dangerous than native predators because their prey, such as numbats and bettongs, are naïve to the hunting tactics of alien predators.
In contrast, where predators and prey have coexisted for long periods, prey often respond by developing behaviours and bodily defences such as camouflage colouring that reduce detection or help them escape if they encounter a familiar predator.
"The finding brings new insight and urgency to the challenge of how best to target management programs aimed at protecting native species from predation," says Dr Peter Banks, UNSW biologist and report co-author.
"More than a century after the introduction to Australia of predators such as the fox their impact continues, and ongoing predation pressure means that remnant populations of prey animals like numbats and bettongs are more vulnerable to extinction from other pressures such as diseases and habitat loss."
The study assessed the impact on alien predators on populations of animals, birds and reptiles by evaluating 80 high-quality research studies from around the world. Predators ranging in size from wolves, lynx and coyotes down to rats were included.
The research reveals that alien predators have done the most damage in Australia, whose native fauna have long been protected by the continent's geographic isolation. According to the World Conservation Union, Australia has nine of the world's 14 worst invasive mammals (domestic cat, goat, grey squirrel, mouse, pig, rabbit, red deer, red fox, ship rat).
Scientists believe that more frequent contact between predator and prey populations in contiguous continents such as Eurasia, Africa and the Americas has made prey populations less naïve to alien predators by exposing them to similar predator "archetypes".
In contrast, Australia’s unique marsupial fauna have never had predatory species like feral foxes and cats until recently. Such alien predators were shown to have worse negative impacts than some classic predators, including large carnivores such as wolves.
Case study: foxes and the brush-tailed bettong
In the early 1800s, Australia’s brush-tailed bettong - a medium-sized kangaroo-like marsupial - was commonplace in central New South Wales, South Australia and the southern regions of the Northern Territory and Western Australia.
However, the population and range of bettongs began shrinking during the 1900s following the release and spread of foxes and rabbits across the continent. Many other species – up to two dozen -- are thought to have become extinct during this initial wave of invading alien species.
By the 1970s, the bettong was considered as an endangered species with the only surviving mainland populations found in small pockets of forest in Western Australia. However, even these remnant populations were still being preyed upon by foxes and by the late ‘70s the species was threatened with extinction.
Following an intensive program of fox-control initiatives, bettong numbers eventually rebounded by more than 20-fold, demonstrating that fox predation had continued to have a devastating impact on bettongs after more than 150 yeas. No native predator anywhere on earth has had such a profound negative impact on their prey.
Dr Peter Banks | EurekAlert!
Obstructing the ‘inner eye’
07.07.2017 | Friedrich-Schiller-Universität Jena
Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
21.07.2017 | Earth Sciences
21.07.2017 | Power and Electrical Engineering
21.07.2017 | Physics and Astronomy