Diversity: not a sure winner

Its generally assumed that species diversity helps a disturbed ecology to be nurtured back to health. But a recent study has shown otherwise. M Sankaran of Syracuse Universityusahas conducted a study on the disturbance of grasslands in southern Western Ghats. The responses of grasslands to fire and simulated grazing in Mundanthurai plateauTamil Naduwere analysed to gauge the changes caused in species diversity.

The study focussed on the ability of ecosystems to spring back to their original state after a bout of disruption. The disruptions can occur in the form of fire to floods. The recovery of vegetation after disturbance can determine the ability of an ecosystem to support a food chain for dependant organisms. The popular view is that diverse habitats tend to be more stable in face of disturbance. But when the area was subjected to controlled firesthe demarcated plots with high species density were found to respond no beter thatn the ones with lesser number of species. Plots dominated by lime-grass were found to become more stable than other plots. The rapid recovery of lime-grass is attributed to its fast rate of growth. Sankaran's study also demonstrates that the in-built resilience of certain species and habitat types is evidence of their long-term adaptation to human