No wolves have trod the Scottish Highlands for more than 250 years. Meanwhile, the local red deer, with no natural predators, have been grazing the hillsides bare, and there's been talk in Scotland about the possibility of bringing wolves back. Now a U.S.-Australian research team is arguing that wolves would be a good way to restore the ecology--not just by reducing the numbers of deer but also because they would significantly change deer behavior by creating a "landscape of fear."
Scientists headed by Adrian Manning of the Australian National University in Canberra have been studying the effects of the reintroduction of wolves into Yellowstone National Park in the northwestern United States, which occurred in the 1990s. The purpose was "mostly to get the wolves back as native species," says William Ripple, a professor of forest ecosystems and society at Oregon State University in Corvallis. But there was an unforeseen bonus: Not only did the elk population go down, but there have been "major ecological effects," Ripple says. The elk now steer clear of areas where they perceive risk from wolves, leading to the regrowth of aspens, willows, cottonwood trees, and berry-producing shrubs. That in turn has supported the resurgence of beaver and bird populations.
In Scotland, says Ripple, "we want to broaden the discussion not just to the intrinsic value of the wolves but to the ecological effects." The red deer have been nipping Scots pines in the bud, so now the pine population has some trees as old as 300 years but no young trees. The deer have also laid waste to the birch population. In a paper in press in Biological Conservation, the same team that studied Yellowstone recommends that a large-scale experiment be carried out, perhaps on an island, to see if the highlands could support a population of Canis lupus. Ripple says the Scottish red deer are the same species that in Yellowstone Park are called elk, and the wolf in question is the same gray wolf.
Such an experiment is a "sensible idea" in the opinion of Timothy Coulson, a population biologist at Imperial College London. It would require a lot of land--at least 1300 square kilometers, he says. The average wolf needs about 260 square kilometers to roam in. And "to draw solid conclusions, ideally you need two or three packs of wolves"--a couple of dozen individuals--as well as many hundreds of deer. Nonetheless, says Coulson, "My guess is, were wolves to be introduced in Scotland, we would see similar effects" to those in Yellowstone.