David Tilman found that plots with more species showed less year-to-year variation in total biomass. He also showed that in his experiments, increased diversity contributed to higher productivity. Hence, we know that rich biodiversity is essential for ecosystem health as well as imperative for the very survival of the human race on earth. Besides from direct benefits like food, fibre, firewood etc. there are many indirect benefits we receive through rich biodiversity such as pollination, pest control, climate moderation and flood control. Hence, loss of any species that play a major role in ecosystem functioning of a particular area can lead to the its entire ecosystem destruction.