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RE: Predator/Prey

Paul, et al:

The ecosystem is in a constant state of flux - with or without predators.
If the climate changes,  or other things occur, i.e. earthquakes, volcanism,
fire, floods, invasion from other ecosystems by new competition (predator OR
prey) - then the equilibrium is destroyed, however temporarily that may be.
The best we can hope for is that the current state of equilibrium is mostly
maintained.  Take away the wolf (in the Yellowstone example below), and the
equilibrium is upset, probably for some time to come.  Eventually, a NEW
equilibrium is found, waiting for the next change to upset it.

The wolf does serve an important role in KEEPING THE CURRENT STATE OF
ECOSYSTEM EQUILIBRIUM.  It is PART of that ecosystem.  Note that there are
other places where a similar ecosystem exists, but without wolves.
(Usually, humans serve as the top predator/competitor).

The apparent harmony in the 'balance of nature' is only as WE see it AT THIS
TIME!  Some people believe that the American Indian (aka Native American,
aka Amerindian) lived in a balanced way with all of nature.  However, these
people managed to help some extremely large creatures to become extinct.
Mammoth, Giant Sloths, Dire Wolves, and the American Lion to name a few.
The level of technology that the ancient inhabitants had, was just enough to
kill off these animals, but not many others.  They functioned the same way
that the wolf does today - i.e. as part of a mostly balanced ecosystem.
(The arrival of the "White" man, with new technologies, as well as massive
numbers of people, upset the balance that the Amerindians lived in).

Today, we upset the equilibrium VERY frequently.  And we notice it!  (Which
means, I feel, that we should try to slow the changes down, or somehow
mitigate them).

Allan Edels

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Paul Cambridge
Sent: Saturday, March 09, 2002 5:39 PM
To: Dann Pigdon; dinosaur@usc.edu
Subject: Predator/Prey

> Paul Cambridge wrote:

"A wolf in Yellowstone serves a very important niche to keep down deer
populations. We know that
specifically because when we took the wolf out, the deer overpopulated. That
is what I mean by harmony. The wolf is "needed" to fill the niche."

>Dann Pigdon wrote:

"No it's not. Take away the predator, the prey species population explodes.
It may stress the local vegetation to the extent that famine causes the deer
population to crash again. Eventually the deer and the plants will reach a
new equilibrium (provided the deer don't kill off all of their food supply,
or the deer themselves don't all die first).

The wolves may appear to fill a "necessary" ecological role, but only in the
specific ecosystem they happen to exist in. That ecosystem has reached a
specific balance over time BECAUSE the wolves are there. Take them away, a
new balance will eventually be reached, and it would seem that there had
never been wolves there at all."

Ok, take a look at what you just said. It was what I JUST said. Granted the
universe is not going to crumple if the wolf is taken away. But the wolf
being where it is, serves a very important role to sustain somewhat of a
balance in the system. As you just stated, the deer population would
explode, perhaps causing stress to vegetation, nearby cattle ranchers, and
the like. I don't know what you call that, but what I call that is an
unbalanced ecosystem. When population are controlled to an order of balance,
i.e.= predator/prey ratio is healthy and neither one is overabundant, then
it appears to me a system is under less stress and therefore healthy.