From: steinly@topaz.ucsc.edu (Steinn Sigurdsson)
Newsgroups: sci.environment
Subject: Re: Ecosystem "Services" or Functions?
Date: 8 Nov 92 15:09:51
Organization: Lick Observatory/UCO
NNTP-Posting-Host: topaz.ucsc.edu
In-reply-to: alanm@hpindda.cup.hp.com's message of Sat, 7 Nov 1992 01:28:34 GMT

In article <149180048@hpindda.cup.hp.com> alanm@hpindda.cup.hp.com (Alan McGowen) writes:


   Let's be crystal-clear about one point concerning biological usage of
   the term "degradation".  Degradation is loss of functions -- *period*. 
   Not just loss of the functions some or all humans like.

			   *	*	*

   Apparantly I've succeeded in getting across the concept that degradation 
   is loss of ecosystem function -- at least to some extent, and to some
   people. Dean prefers to speak of ecosystem "services" -- which has an
   anthropocentric, economic ring to it -- but then adds that he means services
   "to all inhabitants" of the ecosystem. That's a crucial caveat which 
   Steinn failed to notice, or perhaps he thought "inhabitants" meant 
   "humans":

   Dean:
   >>
   >>   It would seem to me to that a definition of degradation should
   >>   be based more on lost services than the cost of restoring the services.
   >>   If the goal is to shorten Alan's definition, then we would be speaking
   >>   of the loss of services to all inhabitants of the ecosystem that has
   >>   been degraded.  In that sense I would say that degradation is the
   >>   accumulated loss of natural services (or functionality) to all of
   >>   these inhabitants.  An important aspect to keep in mind is that the
   >>   loss does not occur at the same time as the action causing the 
   >>   degradation.  Many effects will take time to work their way through
   >>   the food chain and there are other types of delay effects, also.

   Steinn:
   >
   >Well, arguably net degradation should be measured, eg loss of
   >wetlands entails loss of some services, but the resulting drylands ;-)
   >will in general provide some different services. The problem of
   >comparing apples and oranges then arises, how is loss of one service
   >to be balanced by gain of another. The situation is even further
   >complicated in that in addition to loss of biotic services there is
   >anthropocentric gain, and there is often anthropocentric elimination
   >of harm, some motivation for wetland destruction was elimination of
   >malarial swamps.

   The crucial point is that Steinn tacitly orders the functions in 
   terms of some scale of "importance" -- anthropocentric utility --
   and compares two different ecosystems with different lists of
   functions on this scale of "importance". No ecologist would ever
   do that, for a few reasons: 1) the functions that are subjectively
   "important" are coevolved with functions that are subjectively 
   "unimportant", 2) we don't know all the interdependencies, so we don't
   in fact know all the functions which it objectively takes to support
   the ones that are subjectively important, and 3) biology doesn't 
   revolve around human values any more than the heavens do -- using
   what's subjectively important to humans as a yardstick for what's
   actually important for keeping an ecosystem running isn't likely to 
   lead to improved understanding. 

Alan, you miss the point, it is clear than in general changing the
nature of an environment will affect the inhabitants of that
environment, the problem here is that the objections are raised
because certain inhabitants will lose services without any
consideration of the fact that there is some gain for other
inhabitants. Drying out wetlands clearly affects some species
adversely, but in any accounting of the resulting loss of service
I think some estimate must be made of what (and who) the gains were.
A dried wetland does not become a sterile glass plain, it typically 
either becomes a grassland or occupied by humans. Currently
anthropocentric concerns dominate the decision making process in
anthropogenic changes, if you want other factors to be rationally
taken into consideration you must have some way of evaluating them and
ranking their importance, you _cannot_ simply say we must do
nothing because we know not what we do. If ecologists really want
some ecocentric basis for human actions they have to rank the
priorities, there will be changes in natural systems and they will
be influenced by humans. You must explain not only why the loss
of something is bad, but also why what replaces it is not good enough
to compensate for the loss  - if you don't loke the current metric,
come up with your own and show why it is better.

   [What would astronomers make of the idea that our subjective sense of 
   the stability of the Earth should be the first consideration in 
   cosmology? Just as we have found it necessary to reeducate our subjective

Actually, it is a primary consideration in cosmology, any cosmology
in which the Earth fail to be stable for at least 5*10**9 years
is autonatically rejected.

   Consequently, though biologists (I think beginning with Ehrlich)
   often speak of "ecosystem services" to convey to the public that many 
   of these functions are important to humans, there is the deadly danger 
   that the economic analogy will be pushed too far, as Steinn has done
   here: the idea that we can pick and choose economic services and
   intersubstitute them at will doesn't apply here, because *these* 
   "services" go to make up living systems. With ecosystems, if you like 
   *some* of what they do, you had better leave their species inventories
   pretty much alone. (What is the exact Aldo Leopold quote? "If evolution, 

To be quite brutal, this is not true in general, while Alan makes much
of the limited knowledge that ecologists have of ecosystem dynamics,
and in particular the danger that the wrong action can lead to a
catastrophic collapse of ecosystem function, the converse is usually 
the case, ecosystems are generally robust and can adapt to large
perturbations, further, ecosystems do substitute, if conditions become
hostile to a particular ecosystem, it is generally replaced by a
different ecosystem, often one with a different functionality but
then Alan argues that we cannot declare that any less important
than the one replaced - by Alan's own argument a desert ecology
is just as important as that of wetlands or grassland, so why
bother saving the wetlands? 

  ...

*  Steinn Sigurdsson   			Lick Observatory      	*
*  steinly@lick.ucsc.edu		"standard disclaimer"  	*
*  Just because there's a reason          			*
*  Doesn't mean it's understood              Specials, 1979	*