(is in continuation of what was discussed
in class:
planetary boundary hypothesis, & adaptive cycle theory)
Life on the Earth is subtended by
the whole gamut of processes, which we generalize as ecological.
Let us visualize life on the Earth
to be suspended as shown below.
|
Assuming the
spring indicates the above said processes
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In mechanics, students study
something called law of elasticity.
It states that the extension of a spring is in direct proportion with the load applied to it. Materials obey this law as long as
the load does not exceed their respective elastic limit. Stress at which materials start
to deform irreversibly is called yield point. Number of yield points acting, creates
what is called yield surface. Yield surface is usually considered as five
dimensional.
Applying this concept to the
Earth; it is only logical to presume that as long as anthropogenic pressure is
within the yield point of a given ecosystem, it stands the possibility to
revert back to original state.
The 5D structure to study the
yield surface of an ecosystem can be considered to be comprised of:
1. A plane comprising location (x,y,z) - A 3d location can be
visualized as a proxel (process
element), something akin to pixel, which is more familiar. This includes all primary bio-physical parameters
sensed there in and their dynamics.
2. Time (of observation)
3. Socio-ecological factors. (Social component comes
to picture only when man is a part of the system under study. Say, if we are
studying a pond ecosystem deep inside the Western Ghats/ African or Amazonian
forest, untouched by modern man,
this dimension reduces itself to ecological. These are scenarios, where man can
still be considered as a natural animal.
Whilst, if we are studying Ashtamudi/ Victoria/
Chad lakes, those which are extensively and destructively interfered by modern man the social arm dominates the
ecological arm.
The problems for the class are:
A. Attempt to arrive at the components that can define
the yield criterion for a given case. Let us take the more familiar Ashtamudi
lake.
B. Explain the behavior of basic metaphors (ball,
basin, key variable, threshold) vis-à-vis yield criterion of Ashtamudi lake.
Yield criterion concerns the
limit of elasticity under combination of stresses.
You
would find that although it is always not possible to ascribe a cause and
effect to all the components, it still does make sense to move forward from
established concepts of physics in reaching a holistic picture and more importantly a quantitative estimate
for ecological resilience.
We
shall discuss further in the class.
