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This article originally provided by Science and Technology June 6, 2006 Biodiversity aids biological life The role of biodiversity in stabilising ecosystems is a reality to be believed, says S Ananthanarayanan. Prof David Tilman along with others at the University of Minnesota put current beliefs about the importance of biodiversity to the test, as reported recently in the journal Nature. Ecologists have long suspected that biodiversity affects various aspects of ecosystem functioning, but there has been a great debate among academic researchers because we lacked rigorous experimental tests, Prof Tilman said in a communication.Many species growing together help each other to maintain nutritional value of the soil as well as in combating parasites. If a plantation consists largely of a species that draws more of particular nutrients from the ground, those nutrients are likely to be depleted. But if there is a variety of species, then the mix of nutrients drawn would stabilise after some time. And the mechanisms that replace the nutrients, like nitrogen fixation and seepage, can keep the level of nutrients adequate for the different dependant species. If one species is higher in number, the particular nutrients it used most, would begin to reduce and the growth of the species would slow down. The mix of species in the forest would thus remain stable so long as conditions like rainfall, sunlight, soil quality remain unchanged. Nutrition apart, a specialised bio-system, like a plantation of only teak, is a sitting duck for parasites. A natural forest has the diversity of mutually supporting species, co-operating both against predators as well as in sustaining the nutritional viability of the land. A parasite that selectively attacks teak would find the presence
of other species as an impediment to undisturbed multiplication.
Similarly, the teak would protect other species against parasites
that threaten those species. If one species increased out of
proportion, these very parasites would get active and keep down the
population of the runaway species.
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