Predators
Back40 at
Crumb Trail has an interesting view on predators and their role in the environment.
He starts off with a quote from Aldo Leopold from
Think Like a Mountain:
"I have lived to see state after state extirpate its wolves. I have seen every edible bush and seedling browsed, first to anemic desuetude, and then to death."
And then goes on to cite a recent Oregon State University paper:
Predators change the behavior of prey.
Research about wolves that began in Yellowstone National Park has been replicated in an adjacent area, and a growing body of evidence leads scientists to conclude that this historic predator may have an ecological impact far more important than realized in the American West.
The near extinction of the gray wolf across most of the West in the past century now appears to have removed the natural element of "fear" from these ecosystems. It has triggered a cascade of ecological effects on everything from elk populations to beaver, birds, fish, and even stream systems - and helped lead directly to the collapsing health of aspen and some other tree species and vegetation...
There is a bit more of the paper quoted and then Back40 comments:
bq. Though the researchers note that humans alter prey behaviors too I think that they understate the historic role of humans. Like wolves humans took prey of all sizes in all seasons and knew the habits of prey animals. They were patient and lethal even at a distance so they were difficult to detect and avoid. Sport hunters are blundering, smelly avoidable threats compared to those who hunted to live.
bq. I also think that they understate the effects of fear. The damage to streamside Aspens isn't due to selective browsing so much as loafing near water. Elk and deer are ruminants and
must spend time loafing. They regurgitate forage that has been partially digested and chew it again to expose more surfaces to digestive bacteria. Cud chewing is an integral part of their digestion process, an evolved ability that allows them to get much more nutritional benefit from forage than non-ruminant ungulates such as horses. They need to relax to do this and they like to be near water. When they loaf near water they also trample and browse more in the area. They won't loaf there if it's dangerous, they'll find a place where they aren't so anxious about attack so that they can relax and digest.
There has been a lot of comment from the environmentalists that stream cover is important to the 'recovering' Salmon runs. Once again, the big picture is not mentioned, just the political fragments.
As for here, we have coyotes, big cats, deer and elk. We also have great cover near the two streams on our property and the apple trees are doing fine (so far). We have to keep our household pets in at night but having them curled up at our feet is a minor price to pay for having a comfortable ecological balance happening outside...
Posted by DaveH at December 8, 2004 9:10 PM