Preserving all forms of life holds for a more promising eco-future
THE new buzz word in environment
circles is biodiversity which is the
diversity of life in all its ramifications - the different communities
that make up an ecosystem, the different species that make up communities, the variable individual organisms that belong to each species, and
the genetic variation that we see
between and within individual
organisms.
The strongest arguments yet for
conservation are economic: benefits
like food and medicines, not to speak of
useful genes in the wild plants, animals
and microbes which may be useful and
even necessary some day. But if that is
all there is to it, why really worry about
biodiversity per se? As long as we have
some representative samples of various
species surviving somewhere in the
world, our needs - present and future
- should be satisfied. Is it really necessary to preserve biodiversity in its totality? While there was not much scientific
evidence to support this viewpoint earlier, research has now established the
importance of preserving biodiversity in
its entire whole. The complex network
of interrelationships between different
species in each ecosystem need to be
preserved for the well being of not only
our ecosystems and but also the health
of their life support systems.
A recent experiment conducted at
the Imperial College in England provides convincing evidence that biodiversity per se is indeed essential for the
well being of ecosystems (Nature,
No 368, 1994). The experiment used 14
models of terrestrial microcosms maintained in an ecotron. A microcosm, as
the name implies, is a miniature ecosystem maintained as naturally as possible
and an ecotron is a system of controlled
environmental chambers designed for
maintaining such microcosms. Each
microcosm in the experiment contained
producer species, primary consumers,
secondary consumers and decomposers.
Six of the microcosms had high biodiversity with 31 species each, four microcosms had intermediate levels of biodiversity with 15 species each and another
four microcosms had low levels of biodiversity with nine species each.
Self-pollinating herbaceous annual
plants represented the producers; mollusks and insects represented the prima-
ry consumers; insect parasitoids represented the secondary consumers and
collembola and earthworms played the
role of decomposers. There was clear
evidence that biodiversity levels
altered the functioning of the
ecosystems. Perhaps the most
important finding was that carbondioxide consumption as well as
plant productivity decreased with
decreasing biodiversity. Decomposition, nutrient retention and
er retention rates were also sigwat
nificantly affected by levels of biodiversity, although they did not vary
between high, intermediate and low
biodiversity microcosms in a consistent manner.
Taken together these results provide
the first clear dernonstration that loss of
biodiversity indeed alters the functioning of ecosystems. We can now argue
with greater justification that merely
saving individual species in different
locations is not enough. It is important
to preserve the natural levels of
biodiversity in different habitats and
retain the complex networks of species
relationships.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.