This summer — like almost every summer for the past decade or so — was rife with headlines about people being assaulted by wild animals. “Seven teens attacked by grizzly in Alaska’s Talkeetna Mountains,” read a headline in the Anchorage Daily News on July 25, 2011. And, “Two teenagers have life-threatening injuries after being mauled by a grizzly bear while on a survival skills course in the Alaskan wilderness,” the first line of a Guardian feature informed us.
The italics on the words “mountains” and “wilderness” above, however, are mine. I think it noteworthy where these events took place. Against our ever-increasing penchant for developing remote areas and fragmenting wildlife corridors, the world’s largest predators have been squeezed onto smaller and smaller pockets, with nowhere to go but the mountains and the wilderness. Today, grizzlies, wolves, tigers and lions are having trouble finding room to be grizzlies, wolves, tigers and lions. And, without them, our planet is in big trouble.
A recent report authored by twenty-four scientists at institutions around the globe and published by the National Science Foundation (NSF) has found that the decline of large predators and other, what they call, “apex consumers,” at the top of the food chain, has disrupted ecosystems worldwide. After perusing results from a wide range of terrestrial, freshwater and marine ecosystem studies, the scientists concluded “the loss of apex consumers is arguably humankind’s most pervasive influence on the natural world.”
But given our current relationship with top predators, is there any way we can make room for them in our lives?
When non-human animals and humans collide, it is almost invariably the non-human animals who suffer. Just look at the two news stories mentioned above, where words like “attacked” and “mauled” are used. The teenagers inadvertently surprised the grizzly, who had a cub, and its actions were most likely “protective” — at least from the animal’s point of view — rather than combative. That kind of verbiage echoes a similar, recent event in Yellowstone National Park, where a bison “gored” a woman who was purposely striding toward it, in what could have been interpreted by the animal as an aggressive act.
According to James Estes, a marine ecologist and evolutionary biologist at the University of California–Santa Cruz and the lead author of the NSF report, the decline of the world’s largest predators — largely due to hunting and habitat fragmentation — has far more devastating consequences than just a diminishing of a species’ population numbers. An ecosystem’s vegetation, wildfire frequency, infectious diseases, invasive plants and animals, water quality, and nutrient cycles are all impacted when a top predator is removed. When a change at the top of the food chain triggers a string of effects that moves down through the descending levels, the term trophic cascade is used.
For example, the extirpation of wolves in Yellowstone National Park led to overbrowsing of aspen and willows by elk; the reintroduction of wolves allowed the vegetation to recover. When sea otter populations plummeted, coastal ecosystems suffered dramatic changes. Sea otters maintain coastal kelp forests by controlling the number of kelp-grazing sea urchins. And the decimation of sharks caused an outbreak of cow-nosed rays and the collapse of shellfish populations in many estuarine habitats.
The predator next door
Unfortunately, large predators such as grizzly bears and wolves can’t survive on an acre of land. These types of animals need large territories, so making sure they have enough room to go about their livelihoods often conflicts with human needs and goals. Leaving wilderness areas in Alaska, Nebraska or Montana undeveloped might mean doing without another oil pipeline. Letting the mountains be “mountains” might mean forgoing another mine.
In my own state of Wisconsin, I have watched as more and more people move into the Northwoods. Many of the newcomers feel there are too many wolves here (about eight hundred), and that having them nearby is just too dangerous. The wolves have to go.
But if the goal of conservation is to restore functional ecosystems, then it would seem that protecting and keeping an area’s large predators is fundamental.
The question is: Would you mind living next door to a predator?
Feature photo: The planet’s largest predators are being squeezed onto smaller and smaller pockets. ©Eric Rock