Why We Need Carnivores

Carnivores get a bad rap. Just think about the last time you watched a nature documentary. It’s easy to marvel at the Zen-like beauty of a herd of reindeer as they munch peacefully on vegetation. It’s decidedly less pleasant to watch a wolf rip a bloody chunk out of the side of one of those ungulates moments later. But as an article in this week’s Science details, gory eating habits aside, these predators remain important members of their respective ecological communities, a fact we would do well to remember.

Arian Wallach of James Cook University in Australia and her colleagues set out to explore the ecological roles and conservation status of the 31 largest carnivorous species around the world. “The article draws on the accumulated research on trophic cascades published in scientific literature and in IUCN (International Union for Conservation of Nature) compilations,” Wallach told me via email.

What they found was that the ecological roles of predatory animals are far more complex than previously imagined. The historical view of carnivores, of course, has been that they are consumers of resources and little else, but this is far too simplistic. In fact, the ecological influences of these large carnivores are myriad. It may seem obvious, but we could do with a little reminder now and then, especially when human population size and consumption of resources are, according to the article, "one of the most insidious threats to carnivores."

A sampling of predator's roles: They prey on herbivores and act as competition for other predators, controlling both populations in the process. The former activity encourages the flourishing of carbon-storing plants, which act as a buffer to climate change. Through preying on sick ungulates, these carnivores can prevent disease that could otherwise spread to livestock. Some predators even provide economic benefits, acting as tourist attractions in places like Yellowstone, which brings in $22 million to $48 million annually on the proverbial back of the gray wolf alone.

Wallach and her colleagues further provide the aftermath of the flooding of a Venezuelan forest as evidence of the underestimated role of predators. Prior to the flood, the forest was a “productive tropical system… composed of a species-rich food web with multiple linkages among species.” But when the water arrived, many species of predator, including big cats, raptors, and snakes, perished.

This didn’t just affect those animals that the carnivores directly preyed upon. “This loss of predators had cascading effects on species of pollinators, seed dispersers, seed predators, folivores, and mesopredators,” the researchers write. It even affected the forest’s soil, changing the ratio of carbon and nitrogen within.

Another takeaway from the Science report is that, despite their individual ferocity, carnivorous species on the whole are a lot more fragile than they may seem. The researchers note that large carnivores in particular are characterized by “low population densities and reproductive rates with high food requirements and wide-ranging behavior.” These attributes cause friction between the predators and humanity, and are responsible for “[making] them vulnerable and poorly able to respond to persecution.”

Because of this fragility—as well as humanity’s tendency to fear and malign predators—conserving these animals will require motivation on a worldwide scale. Already, 61 percent of the 31 large carnivores studied are classified by the IUCN as vulnerable, endangered, or critically endangered.

“As a global society, we have to decide to protect large carnivores and their habitats wherever they remain, and where possible, reintroduce them back into areas where they have been extirpated,” Wallach told me. To this end, she and her team advocate for the creation of a conservation-focused Global Large Carnivore Initiative, modeled on the Large Carnivore Initiative for Europe whose vision is “to maintain and restore, in coexistence with people, viable populations of large carnivores as an integral part of ecosystems and landscapes across Europe.”

Coexistence is key. We must figure out a way to live alongside the gray wolves in the Rocky Mountains and the black bears in New Jersey, for example, preferably without excessive killing from either side. In fact, Wallach says, culling can often cause more severe issues by promulgating social problems and territory breakups amongst animals.

The solutions won’t necessarily be easy to come by, but coexistence is definitely possible, even if it may require some creativity. In a TED talk (above) that Wallach shared with me, a teenager from Kenya describes how he has successfully used blinking lights to keep carnivores from feeding on his father’s livestock for the past two years.

But if we fail at conserving carnivores, what will happen? The answer is cloudy. Studies like this do add more dimensionality to the subject, though Wallach suspects that even scientists like her don’t fully grasp the ecological importance of Carnivora.

“The impact of losing these carnivores globally is difficult to fathom, but would probably be of a magnitude not unlike a major shift in climate,” she explained. “Protecting large carnivores is equally difficult to imagine—how much greener would the world become?”

@heyiamlex