I'm afraid I have far more radical ideas about humans and ecosystems.
In my opinion, humans are animals, not unlike any other animal on the
planet. Any possible dichotomy between humans and other animals would be
arbitrary from an ecological point of view, that is, anthropocentric. I
believe that the big "difference" perceived between Homo sapiens and
other organisms (not only animals) is merely the effect of the
extraordinarily disproportionate interest we express for H. sapiens.
For instance, let's think at the Gaia hypothesis: does anyone think that
the impact of H. sapiens on the biosphere is quantitatively and
qualitatively more important than any species of denitrifying bacteria,
or than cyanobacteria? How rapidly the biosphere biogeochemical cycles,
which are at the base of any biological process on Earth, would change
if a crucial procariote strain or lineage suddenly disappears? My
educated guess is that such changes would be much more drastic than any
"global change" induced by greenhouse gases released by H. sapiens in
the atmosphere. Fortunately (also for us, I would say), such pivotal
organisms cannot apparently be threatened by human activity on Earth.
Analogous examples can be made for several species of insects, with huge
biomasses and numbers of individuals.
I personally do not think that H. sapiens is the "dominant species" on
the planet. Its ecological impact on the biosphere is gradually
decreasing as we consider organisms that are less and less ecologically
(and up to a certain extent, phylogenetically) related to (e.g.
interacting with) H. sapiens.
This is probably the main reason why we are the only hominid species on
the planet, and why so few apes presently survive (most being at risk of
extinction). This is the reason why H. sapiens drove the majority of
mammal megafaunas to extinction much before industrialization, and one
of the reasons why there are so many environmentalist campaigns for
vertebrates than for arthropods, protists, or procariotes (apart from
anthropomorphic and demagogical issues).
It is clear that the ability of H. sapiens (or better of some its
populations) to modify its habitat for his own survival is driving the
colonised systems to their carrying capacity, rapidly inverting its
adaptive value. But "carrying capacity" is a concept based on "what must
be carried by the system"... making this essentially a problem for H.
sapiens and for "ecologically related" species.
Nonetheless, I think that the same permanence of this trait in our
r-selective culture is indeed based on this obsolete dichotomy: H.
sapiens and everything else.
I think that as ecologists, we should be very clear on this point, if we
propose to manage our habitats and co-evolve with other organisms by
means of one of our best adaptations: mind.
It is often advantageous to focus on a single organism (e.g. H. sapiens
or Aedes albopictus) or on a group of organisms, to address specific
ecological problems. Nonetheless, I think that ecologists should promote
and sustain a more holistic concept of ecology and ecosystems, with no
permanent focus on a single portion or process; we reached the limits of
our habitat: the biosphere must be managed as a whole, and all parts are
important.
These my two cents.
Cheers,
G
Gianluca Polgar, PhD
Senior lecturer in Ichthyology and Ecology
Institute of Biological Sciences
Faculty of Science, University of Malaya
50603 Kuala Lumpur, Malaysia
skype: gianluca.polgar
http://www.mudskipper.it
gianluca.pol...@gmail.com
Il 29/06/2010 2.51, Ajay Sharma ha scritto:
I would suggest reading O'Neill, Robert V. (2001). Is It Time to Bury the
Ecosystem Concept? (With Full Military Honors, of Course!). *Ecology*, 82:
3275-3284.
The eminent authors concludes in the article there is need to make revisions
in the concept of ecosystem. Especially, as far as the role and place of
humans is concerned. He points out that the humans are the ultimate invasive
species in the ecosystem that alters both the biotic and abiotic components.
A must read and very interesting article.
Ajay Sharma
PhD Student,
SFRC, UF, Gainesville, FL
On Sat, Jun 26, 2010 at 10:19 PM, Daniel A Fiscus<dafis...@frostburg.edu>wrote:
Fabrice,
An interesting and evocative question and dilemma! I should really think on
it over time and reply in depth...but some thoughts of the top instead...
I agree with other repliers that the definition really does not exclude
humans per se...unless we focus on the "special" aspect of your ID of humans
as "special animals". So I think the CBD definition is OK in the broadest
sense of all animals.
But I also agree that humans are special animals...so what could we change?
My core idea of ecosystem as I remember Tansley to have originally coined
it mentioned and emphasized "reciprocal" influence between the abiotic and
biotic realms. And I think it a reasonable extension to also suggest the
definition so far includes a sense of a balanced reciprocity...not
necessarily equilibrium, stasis, homeostasis or simple stability...but still
in general a kind of equal weighting, value, importance, dominance, or
causal driving by the biotic and abiotic realms.
If we tried to address what is special about humans as animals, in this
context of ecosystem as a functional biotic-abiotic unit...what to
emphasize?
One option would be to say that when humans enter the integrated functional
whole of an ecosystem, the relationship is no longer reciprocal or balanced
between biotic and abiotic realms. This does not necessarily have to mean
that this change is "bad", just that it is different from ecosystems without
humans. The change would be compatible with the idea of the anthropocene era
in which humans are the main driving force of change...even geologic,
atmospheric, biogeochemical, species extinctions, etc. changes...on the
planet. Another very general analogy would be to say that without humans the
organisms and communities within ecosystems (biotic) adapt themselves mainly
to survival needs as defined by abiotic changes, but humans (biotic) adapt
(alter) the abiotic (and biotic) environment to our own needs. This is
grossly general...and not even a clearly separable difference between humans
and other species, especially those studied as "ecosystem engineers", but it
is a rough start.
So...a revised approach would be to leave the definition of ecosystem as it
is (or one of the other classic or widely used versions by Odum and others),
but to add some modifier to another term or type of ecosystem and define
that one differently. This might be "coupled human-natural ecosystems" or
"human-dominated ecosystems" or "human ecosystems" or "ecosystems with
humans".
But I think you open a can of worms that has to remain fuzzy and
open-ended, because I think it an open question as to whether we humans can
continue this lopsided relationship and continue to alter the environment to
our needs and wishes. If the pendulum swings back as we reach the
environmental limits of the planet, then the old and original ecosystem
definition may be fine. If we find some way to transcend these planetary
limits or "boundaries"...then we humans really are special enough to require
an expanded definition of ecosystem.
Some thoughts...would be fun to discuss more...
Dan
--
Dan Fiscus
Assistant Professor
Biology Department
Frostburg State University
308 Compton Science Center
Frostburg, MD 21532 USA
301-687-4170
dafis...@frostburg.edu
-----Original Message-----
From: Ecological Society of America: grants, jobs, news on behalf of
Fabrice De Clerck
Sent: Fri 6/25/2010 11:20 AM
To: ECOLOG-L@LISTSERV.UMD.EDU
Subject: [ECOLOG-L] Humans in the definition of ecosystems
Dear Friends,
An environmental economist colleague of mine is disappointed with the CBD
definition of ecosystems which gives the impression that only pristine areas
are ecosystems. Can anyone point us to a more recent definition of
ecosystems that explicitly includes humans as an integral part of the
definition?
Here is the original question:
The CBD defines ecosystems as a dynamic complex of plant, animal and
micro-organism communities and their non-living environment interacting as a
functional unit.
I find this boring, as it leaves us humans, as special animals, out of the
picture. When you read it, it is easy to think of pristine environments. Has
there been any reaction or correction of this definition? I need an
authoritative quote that balances the CBD´s
All reactions welcome, and citations welcome!
Fabrice
********************************************************
Fabrice DeClerck PhD
Community and Landscape Ecologist
Division of Research and Development
CATIE 7170, Turrialba, Costa Rica 30501
(506) 2558-2596
fadecle...@catie.ac.cr
Adjunct Research Scholar
Tropical Agriculture Programs
The Earth Institute at Columbia University
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