Tuesday, July 25, 2017


I've nearly finished this book.
I picked it up in Yellowstone last year and it just made the top of the pile!
Wolves were re-introduced to Yellowstone National Park in 1995 after being killed off 70 years before that.
It's very interesting the impact they have had and not at all what one would expect.
There has been a trophic cascade.
That's were the presence of a top predator in an area creates a richer environment.
In this case the wolves, who in Yellowstone eat primarily elk, have caused the elk to change their habits-you know so they won't get eaten by a wolf!
That has given aspen, willow and cottonwood trees the chance to grow as well as other plants and grasses.
Trees attract birds (from songbirds to bald eagles), and small mammals, like the red fox.
Most important to the landscape is that trees allowed the beaver to return which filters the streams and helps the fish, and otters.
The new plant growth has stopped the bank erosion the elk caused, and the beaver's dam's create ponds so the channel is more reliable and less likely to flood.
  It has become a richer environment for grizzly bears as well.
This doesn't even count the insects or the added fertility of the land itself from the carcasses of wolf kills.
Oh, by the way, wolves only kill an elk once in five attempts and are in great danger when they do so.
I found it interesting and now must return to Yellowstone and become a wolf watcher!

This trophic cascade thing is a new idea to me but is backed up by the current situation on Isle Royale National Park, Michigan.
They have been studying the wolves there for a VERY long time -apparently the wolves crossed ice bridges from Canada to settle there-anyway they eat Moose there.
There are currently only 2 wolves on Isle Royale and while they can still take down a moose they cannot make a large enough impact on the moose population to stop the herds from growing.  That has already caused damage to both water and land plants.
They are seriously considering relocating wolves here as well.  
Wolves that already know how to hunt moose!

Just a reminder that top predators, even when they have a very bad rap (like sharks) are very necessary to a healthy ecosystem.


a good yarn said...

I'm sure I watched a tv program about this and it was fascinating (yet it made perfect sense) that removing the wolves had a devastating effect on the ecosystem.

a good yarn said...

I just noticed that the post in my reading list below yours is titled Sheep.