Jane and Forum:
While I might quibble about the difference between "dependent" and "adapted
to" fire, for example, I get the point if what Shevtsov means is that every
single bit of life is an "ecosystem" or a subset of one. There is, however,
a great difference between an assemblage of species that cannot shift for
themselves, but as soon as the "external" influence (landscaping or a farm,
for example) is removed, the maintained life-forms will "revert" to an
ecosystem that is not dependent upon maintenance. Even after a volcano or an
atomic explosion, for example, self-sufficient ecosystems eventually
colonize such sites, without any "help" from culture. Further, the changes
that occur in the absence of fire may well be due to its absence, but there
is no "requirement" that "their structure" be maintained.
WT
----- Original Message -----
From: "Jane Shevtsov" <[email protected]>
To: <[email protected]>
Sent: Monday, March 02, 2009 6:42 PM
Subject: Re: [ECOLOG-L] Ecosystems and agronomy Definition of agroecosystem
Re: [ECOLO G-L] The Role of Ecos
Wayne and forum,
Lots of ecosystems (prairies, chaparral, many pine forests, etc.) are
dependent on fire or other types of disturbance to maintain their
structure. How is this different from being dependent on humans?
Jane
On Sat, Feb 28, 2009 at 6:26 PM, Wayne Tyson <[email protected]> wrote:
Kristin and Ecolog:
I hope I have not been misunderstood. I do not object to the study of
species interactions and habitat conditions in agriculture; I am
concerned, however, that the distinction between "natural" ecosystems and
anthropogenic alterations of them. The distinction I believe useful, if
not critical, is that between a "system" that is DEPENDENT upon external
influence and displacement/destruction of indigenous ecosystems (e.g.,
plowing, planting and maintenance of monocultures and introduction of
other organisms that did not co-evolve with them as a TREND. I certainly
do recognize the value of the study of such phenomena, particularly when
its trend is in the direction of preservation of genetic diversity, not
its reduction. I do seriously question the habit of terming anthropogenic
assemblages of species "ecosystems," as they are quite distinguishable
from "natural" ecosystems. I think scientists in general, and ecologists
in particular, have a duty to do no harm, to pass knowledge along in a
clear and directly honest fashion to the population at large. I think the
distinction is CRUCIAL.
If I am wrong in this, I look forward to being corrected with persuasive
logic and evidence.
WT
----- Original Message -----
From: "Kristin Mercer" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 04, 2009 2:35 PM
Subject: Re: [ECOLOG-L] Ecosystems and agronomy Definition of
agroecosystem Re: [ECOLO G-L] The Role of Ecos
Dear Wayne,
The definition you received from another ecologger is a good
one. Given your concern about the term agroecosystems, I think the
best way to understand agroecosystems is to see that they are
connected to, but distinct from, the natural or urban or managed
ecosystems around them. Just as savana may be surrounded by forests,
agroecosystems can exist within a matrix of other kinds of
ecosystems. So although parts of agroecology does study the effects
of agriculture on natural ecosystems, it is certainly not limited to
that perspectives. Studies of weed community dynamics, insect pest
population genetics, nutrient cycling under various management
practices (i.e., studies within the agroecosystem) all fall within
agroecology.
I would think that few agroecologists see themselves as promoting the
"business as usual" agriculture or "destruction and degredation". In
fact, within the context of needing to grow food on our landscapes, I
think most ESA members would be cheering agroecologists along. In
that vein, the agroecology section of ESA is alive and well.
Cheers,
Kristin
At 06:03 PM 2/3/2009, Wayne Tyson wrote:
Ecolog:
I received the following off-list response to my enquiry about the
definition of agroecosystem:
"Agroecosystems are best understood as the unit of study of
agroecology, which looks at agricultural production systems in terms
of ecosystem prosperities: e.g. stability, resilience, disturbance
regime, stocks and flows of nutrients and energy, and niche
dynamics, etc. Look to Miguel Altieri for a thorough, scientifically
based discussion of agroecology. Additionally, the wikipedia article
on agroecology is more substantial and less vague than the one
agroecosystems."
I agree with the respondent that "the wikipedia article on
agroecology is more substantial and less vague than the one
agroecosystems." Agro-ecology seems somewhat less of an oxymoron
than agro-ecosystem. Certainly the study of ecosystems and the
effects of agriculture upon them is legitimate, but it seems to me
that the use of the term agro-ecosystem implies that the two are
somehow interdependent or that agriculture is just a part of the
ecosystem in which it stands. On the one hand, there seem to be two
opposite impulses at work within the field, one trying to minimize
the adverse effects of agriculture upon ecosystems and recognize the
positive effects of ecosystem preservation, conservation, and
restoration upon their integration with agricultural practice, and
on the other the various hyphenated "dash" ecosystem terms seem to
be, intentionally or unintentionally, a front for business as usual
and a cover for continued expediency as the primary driver of
ecosystem destruction and degradation.
Am I missing something here, or should ESA perhaps take a scientific
position on this issue? If so, "ecologgers" might be a good place to
begin drafting a more unified, or at least less vague definition?
Even if they just buy into one or more of the existing ones? Or
throw them all out?
I should imagine that the ecological economists would be "all over"
this. Are they?
WT
Kristin Mercer
Assistant Professor
The Ohio State University
Department of Horticulture and Crop Science
310F Kottman Hall
2021 Coffey Road
Columbus, OH 43210
Office: (614) 247-6394
Lab: (614) 247-8626 (341 Kottman)
Fax: (614) 292-7162
email: [email protected]
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-------------
Jane Shevtsov
Ecology Ph.D. student, University of Georgia
co-founder, <a href="http://www.worldbeyondborders.org";>World Beyond
Borders</a>
Check out my blog, <a
href="http://perceivingwholes.blogspot.com";>Perceiving Wholes</a>
"Political power comes out of the look in people's eyes." --Kim
Stanley Robinson, _Blue Mars_
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