The rapid loss of top predators such as dingoes, leopards and lions is causing an environmental threat comparable to climate change, an international group of scientists has warned.

 

A study by researchers from Australia, the US and Europe found that removing large carnivores, which has happened worldwide in the past 200 years, causes a raft of harmful reactions to cascade through food chains and landscapes.

 

Small animals are picked off by feral pests, land is denuded of vegetation as herbivore numbers increase and streams and rivers are even diverted as a result of this loss of carnivores, the ecologists found.

 

The research looked at the ecological impact of the world’s 31 largest mammalian carnivores, with the largest body of information gathered on seven key species – the dingo, grey wolf, lion, leopard, sea otter, lynx and puma.

 

In Australia the downfall of the dingo, which has been largely pushed out of the country’s eastern and southern states, has had a number of detrimental effects. Dingoes have been culled to prevent them preying on sheep, while inter-breeding with dogs has also had an impact.

 

Further afield, researchers found that the reintroduction of wolves to Yellowstone national park in the US caused a reduction in deer numbers, in turn benefiting the park’s trees and plants.

 

The spread of Lyme disease in the US was partially attributed to booming deer numbers, which host the ticks that carry the disease, while an increase in the number of herbivores grazing is thought to change the flow of local rivers, making them straighter and threatening creatures that dwell in slow-moving waters. Loss of vegetation also removes key carbon storage from the environment.