On the same day we learn that lions are all but extinct in West Africa, a new study points to the devastating ecological and environmental impacts of losing large carnivores across the globe.
The new report, which now appears in Science, considered the ecological and environmental role of over 30 large carnivore species, 17 of which now occupy less than half of their former ranges. More than 75% of all large carnivores are now in decline. Specific species include lions, dingoes, wolves, otters, and bears. The disturbing decline in predator populations can be attributed to habitat loss, hunting, and loss of prey — losses that are being felt from the tropical regions straight through to the Arctic.
"Globally, we are losing our large carnivores," noted lead author William Ripple in a statement. "Many of them are endangered," he said. "Their ranges are collapsing. Many of these animals are at risk of extinction, either locally or globally. And, ironically, they are vanishing just as we are learning about their important ecological effects."
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No doubt, these predators, often considered a headache, provide essential services to both ecologies and the environment. The loss of certain large carnivores, including African lions, leopards, Eurasian lynx, cougars, gray wolves, sea otters and dingoes, is resulting in widespread "trophic cascades."
Owing to a decline in cougars and wolves, for example, researchers have seen a dramatic increase in herbivores like deer and elk, causing disruptions to vegetation, birds, and small mammals, along with changes to other parts of the ecosystem. In environments experiencing vegetation loss, for example, researchers have observed increased soil erosion.
Likewise, the loss of lynx populations has been tied to an abundance of roe deer, red fox, and hare. Even the oceans are not immune; the decline in sea otters through orca whale predation has led to a rise in sea urchins and loss of kelp beds.
"Human tolerance of these species is a major issue for conservation," Ripple said. "We say these animals have an intrinsic right to exist, but they are also providing economic and ecological services that people value."
Read the entire study at Science: "Status and Ecological Effects of the World's Largest Carnivores."