In Yellowstone National Park in the U.S., the reintroduction of wolves after decades of absence is now allowing willow, aspen and cottonwood trees to thrive once again in some places, instead of being eaten as young shoots by elk. This is helping to control stream erosion. The interactive webs of birds, insects, fish and beaver are returning to health. These processes, called "trophic cascades," result when the loss of one key predator can have cascading effects on an ecosystem that go far beyond the obvious.
The new report is just being published in the journal Biological Conservation, co-authored by Ripple, Adrian Manning of the Australian National University in Canberra, and Iain Gordon of CSIRO Sustainable Ecosystems in Australia.
It outlines a situation in Scotland that may be especially challenging. The land has been so systemically changed, for such a long period, that even local residents may have no memory of what it once looked like.
"The long-term absence of any organism or ecosystem from a region can be a major barrier to restoration," the scientists wrote in their report. "Over generations, human memory of an ecosystem, or the presence of a particular organism diminishes, and expectations of good ecological conditions are gradually lowered. The idea of reintroductions and large-scale ecological restoration seems too intractable, complex, open-ended, confronting or radical to be feasible."
In light of that, the scientists are proposing a substantial test case on a Scottish island or a major fenced area that would allow the reintroduction of wolves on a more limited area, and a careful monitoring of their effects on red deer populations, behavior, and hopefully
|Contact: William Ripple|
Oregon State University