It may not come as a surprise to find that large carnivores around the world are declining in numbers, but what may be startling is just how far-reaching the consequences are likely to be. Large carnivores often have extensive territories, which they roam to catch their relatively large prey. This behavior can put these carnivores in unwanted contact with people and their livestock, which people have frequently responded to by limiting the size of the carnivores’ territories and/or outright killing these animals. And, over the past two centuries, this repeated response has led to clear declines in carnivore numbers around the world.
Specifically, in a study published earlier this month, researchers looked at the world’s 31 largest carnivore species and reported that an astounding 77% of them are declining in numbers, and most – 61% of them – are considered threatened (varying from being vulnerable to being critically endangered). The causes are almost certainly due to our actions. Looking at several of these species, it was found that their territories have decreased so much that, on average, they now occupy only 47% of the area they historically used to. And there are many reasons why we should be concerned about these vanishing predators.
Because large carnivores are at the top of the food web, their presence and numbers affect many other critters – herbivores and plants directly down the web, and broader branches of the web that include smaller carnivores (and partial meat eaters, called mesocarnivores) that compete with the larger ones. For example, take the African lion (Panthera leo). It now roams a shocking 17% of the area it once did, losing territory and numbers due to people defending their livestock. These declines correlate with an increase in numbers of the omnivorous olive baboons (Papio Anubis) in West Africa, where they’re posing such major threats to people’s livestock and crops that some families are keeping their children home from school to protect the farmlands. A separate publication came out earlier this month that focused on the devastating declines of the West African lion specifically – there are thought to now only be 250 adult lions in the West African area, living in fewer protected areas than previously thought, comprising about 1% of their historical range.
Overall, the authors of the global large carnivore study show that the presence of these animals is important not only for maintaining species diversity, but also for human success – declining carnivore numbers is negatively impacting people, as shown by the African lion example. The authors propose the creation of a Global Large Carnivore Initiative to coordinate protection efforts around the world.
So next time you encounter what seems to be a pesky predator – such as a spider, or a chicken-eating fox – you may want to consider its important role in its food web before disposing it. After all, they help to keep your house free of flies and your food containers free of mice, respectively.
For further reading:
- William J. Ripple et al.’s article “Status and Ecological Effects of the World’s Largest Carnivores” in Science
- Philipp Henschel et al.’s article “The Lion in West Africa is Critically Endangered” in PLOS ONE
- ScienceDaily’s article “Loss of Large Carnivores Poses Global Conservation Problem“
- Bob Grant’s article “Large Carnivores Under Siege” in The Scientist
- ScienceDaily’s article “Lions Are Critically Endangered in West Africa”
- Teisha J. Rowland’s book Biology Bytes: Digestible Essays on Animals Both Commonplace and Bizarre