A study of the global decline of large predators such as lions, dingoes, wolves and bears, has found that they play important roles in ecosystems.
Scientists in the United States, Australia, Italy and Sweden examined the ecological roles and conservation status of the largest members of the order Carnivora.
“These are some of the world’s iconic predators,” said co-author Dr Arian Wallach, from James Cook University’s School of Marine and Tropical Biology. “Because of their position at the top of the food web, they frequently come into conflict with humans.”
The study, just published in Science, focussed on 31 species (animals weighing more than 15 kilos) and found that more than three-quarters of them are declining, with 17 species now occupying less than half of their former ranges.
“Globally, we are losing our large carnivores,” said lead author Professor William Ripple, from the Department of Forest Ecosystems and Society at Oregon State University.
“Many of these animals are at risk of extinction, either globally or locally. And ironically, they are vanishing just as we are learning about their important ecological effects.”
Professor Ripple and co-author Robert Beschta have documented impacts of cougars and wolves on forest and streamside vegetation in Yellowstone National Park and other reserves.
Fewer predators, they found, led to an increase in browsing animals such as deer and elk, which in turn disrupted vegetation, shifted birds and small mammals, and triggered a series of changes.
“Where large carnivores have been restored, such as wolves in Yellowstone or the Eurasian lynx in Finland, ecosystems have responded quickly,” Professor Ripple said.
The authors call for a deeper understanding of the impact of large carnivores on ecosystems and the complex roles they play.
Dr Wallach said Australia’s largest terrestrial predator helped to sustain biodiversity and control invasive species.
“Where dingo populations are healthy and stable we see fewer impacts from wild herbivores and smaller predators such as the red fox. That allows vegetation and small native animals to recover,” she said.
“Overall, the suppression of dingoes has probably contributed to the endangerment and extinction of small marsupials and rodents over much of the continent.
“Protecting dingoes must become a conservation priority in Australia if we are to stem the tide of extinctions and recover degraded landscapes,” Dr Wallach said.
Because members of Carnivora need large ranges, the researchers say that protected areas alone will not be enough to save them – we need to find ways to co-exist with predators, in both natural and working landscapes.
The authors call for the formation of a Global Large Carnivore Initiative to coordinate international strategies to protect and restore large carnivore populations.
“We know this is not a simple endeavour,” Dr Wallach said. “People can lose their livelihoods and even their lives to large carnivores. But the more we find out about them, the better we understand how valuable they are to us.
“Coexisting with large carnivores requires a maturation of our society as nothing else quite does.”
Issued September 18, 2013
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