P1252122132UAVTs

1
Barry Commoner's Four Laws of Ecology, as written
in The Closing Circle in 1971.
1. Everything is Connected to Everything Else.
There is one ecosphere for all living organisms
and what affects one, affects all.
Wait! We already did that in the 1800-1900s!
2
Okay fine, now what did the gray wolf normally
eatin this ecosystem?
X
X
X
Ok, a few
Once in a while
Yah Baby!
3
Okay, so what do Elk eat?

When the wolves were removed would you expect the
number of Elk to increase or decrease?
Duh!
If the number of Elk increased, what would you
expect to happen to the Aspen and Willow
abundance?
4
Photo taken 7/17/1997
Decadent (dying) Aspen in the northern Greater
Yellowstone Ecosystem (northern range). All
trees are 100-130 years old. No new growth since
the root sprouts (ramets) have been completely
eaten by Elk. (Page 66 in Yellowstones
destabilized ecosystem by Frederic H. Wagner)
5
Over browsed Aspen stand being replaced by
sagebrush and related species (Photo from the
Northwest Habitat Institute.)
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Aspen stands provide food or cover for literally
hundreds (thousands) of other species, many of
which have declining populations. For example,
Additional information about bird declines due to
lack of wolf predation on large herbivores J.
Berger, et al, 2001. Ecological Applications
11(4)947-960
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Back to willow- For the sake of discussion, does
anything else eat willow plants?
So if the amount of available willow decreases,
what would you expect to happen to the beaver
population?
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Do Beaver have any effect on the environment?
Does anything depend on the Beaver?
So what was once a fast moving stream, is now a
pond containing an entirely new ecosystem and
supporting bank vegetation and creating flooded
valleys which effect the water table.
9
Barry Commoner's Four Laws of Ecology, as written
in The Closing Circle in 1971.
2. Everything Must Go Somewhere. There is no
"waste" in nature and there is no away to which
things can be thrown.
If willow and aspen communities are removed due
to over browsing by Elk or Moose etc, and the
beaver depart because of the lack of food/cover,
can you predict what might happen to the stream
banks and water table of the resulting ecosystem?
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Can you predict what kind of species would be
able to use this ecosystem?
What do you suppose would happen if land managers
tried to re-introduce beaver into this system?
11
Barry Commoner's Four Laws of Ecology, as written
in The Closing Circle in 1971.
3. Nature Knows Best. Humankind has fashioned
technology to improve upon nature, but such
change in a natural system is likely to be
detrimental to that system.
Hmmmmmm now theresan idea. Stay tuned.
12
Barry Commoner's Four Laws of Ecology, as written
in The Closing Circle in 1971.
4. There Is No Such Thing as a Free Lunch. In
nature, both sides of the equation must balance,
for every gainthere is a cost, and all debts are
eventually paid.
13
West Virginia mountain forest view, original
photograph by Jim Clark, Mountain Memories,
Vandalia Press 2003
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(No Transcript)
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David Raups Corollary to Commoners Law