From: russ@wpg.com (Russell Lawrence)
Subject: Re: Self Regulating Populations
Organization: WP Group
Date: Fri, 21 Aug 1992 15:45:07 GMT


Russell Lawrence writes:
rl> Thank you for admitting that these deer are not truly dependent on 
rl> what nature provides.  

From article <BtC0LF.6r7@newcastle.ac.uk>, by J.M.Spencer@newcastle.ac.uk (Jonathan Spencer):
js> I'll be generous and assume that you have simply misunderstood 
js> what I said.  *The* deer (meaning the main herds) live on the 
js> moor.  They *are* dependent on what the moor provides, and that 
js> isn't much.  They were not culled for some years.  The population 
js> increased.  

You say that the moor didn't provide much in the way of food.  Would
you be willing to provide a guesstimate of the caloric intake per
capita?

You also say that the population increased because the deer weren't
culled.  Were the deer starving and yet increasing in population at
the same time? 

js> The moor cannot support an infinite population.  In 
js> the quest for food brought about by competition, *some* 
js> individual specimens of the deer move down onto the low 
js> agricultural land.  Note *some* small number of deer, not *the* 
js> deer, *the* deer remain on the moor.  In order to control 
js> numbers, the LACS has adopted a policy of culling.  So your 
js> statement 

=================================================================
rl> You've described a group of animals that 
rl> are supposedly free from human interference and free from 
rl> handouts, yet they have human crops available for eating...  
=================================================================

js> is *wholly* incorrect.  *The* deer reside on the moorland owned 
js> by LACS.  

You're contradicting yourself.  You've already stated that 
the deer were eating adjacent croplands.  Why did you make
such a statement if it wasn't true? 

js> They do not have crops available, they have heather, 
js> lichens, maybe some rough grasses at the moor's edge, and very 
js> little else.  The few marauders, who have been pushed by pressure 
js> of numbers to seek food by going outside the LACS land, down onto 
js> the low land, will find better food.  *The* deer live on the hill 
js> where there is no human provided food, and no competition with 
js> sheep, either.  But we are digressing.  

No, we're not digressing.  Why did you say the deer were consuming
crops previously if they weren't consuming crops?

js> The point is that the deer on the LACS land are not
js> self-regulating, they just continue to breed, and expand if there is
js> room for expansion, which there is. If your argument is correct, LACS
js> should fence in the deer at which point they will lower their rate of
js> reproduction and settle at some convenient population level. And I ask
js> myself, if that is so, why haven't they done just that?

Good question.  If you'll send me their address, I'll write and ask
them.  Without any data, I'd suspect that the major problem is expense.
It's also possible that they're unaware of the relationship between
fat and fertility.

=================================================================
rl> You've described a group of animals that 
rl> are supposedly free from human interference and free from 
rl> handouts, yet they have human crops available for eating...  
rl> crops that are typically higher in fat and protein than the brush 
rl> material that deer would typically eat.  
=================================================================

js> ha, ha, ha, ha! "brush material"? Russell, do you have any idea
js> what I mean by a moor?

I think so.  If you think I've misunderstood you in some way, why don't
you explain?

js> Consequently, they have recognised that, in the absence of natural
js> predation (eg the European wolf) they are going to have to cull the
js> deer themselves, or get someone to do it for them (but not as a sport).
js> Only they don't consider that a pack of deerhounds (eg the Quorn hunt
js> who own neighbouring land) is an acceptable substitute for a pack of
js> wolves. The LACS advocate that the deer should be controlled by
js> "marksmen using high powered rifles". THis is a very different position
js> from that when they bought the land which argued that the deer would
js> stabalise their numbers to that which the ground could support. They
js> don't, they just expand their range (of course).

rl> Animal populations are, indeed, self-regulating.  And 
rl> animal populations will, indeed, expand their range if given the 
rl> opportunity to do so.  Your example demonstrates that the 
rl> creation and protection of stable, natural ecosystems isn't an 
rl> easy task when the areas in question are surrounding by man-made 
rl> environments like farms.  

js> It demonstrated that in the absence of natural predation, man must
js> either prey on these species, or disease and starvation will do the
js> job...

How much fatty tissue must a female deer have in order to ovulate?
How can a deer be fat and starving at the same time?

js> That is the experience in Scotland where the red deer have
js> expanded to their full range, they have no natural predators (well,
js> golden eagles take the odd calf) they have doubled their population in
js> twenty years and show no sign of stopping, they are causing permanent
js> erosion to the land, they are causing de-forestation...

Are we still talking about the same deer that live on the moors you
described previously?  ... the same deer that had heather, lichens, 
and rough grasses to eat and very little else?    

js> they die in their
js> hundreds every winter from starvation. They are at saturation level,
js> yet we see *no* sign of their numbers levelling off which, is what you
js> say they will do. When?
js> 
js> Before you answer, I should tell you that the (independent, 
js> scientific body) the Red Deer Commission blame the current 
js> problem on a lack of culling of the hinds and are recommending an 
js> immediate cull of not less than 60,000 hinds.  Obviously, the RDC 
js> don't subscribe to your hypothesis.  

As I've pointed out, natural regulatory mechanisms aren't going to 
work in cases where the eco-system is unbalanced for some reason.  
Not knowing all the data, I'm not in a position to dispute their 
decision.  However, the evidence that you've already provided makes
it clear why the population of deer continued to increase in the
aforementioned case, namely this:  They had plenty of food.

-- 
Russell Lawrence, WP Group, New Orleans (504) 443-5000
russ@wpg.com   uunet!wpg!russ
Newsgroups: talk.politics.animals