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Citation. Tilman, D.; Reich, P.B.; Knops, J.M.H. 2006. Biodiversity and ecosystem stability in a decade-long grassland experiment. NATURE 441:629-632.
Abstract. Human-driven ecosystem simplification has highlighted questions about how the number
of species in an ecosystem influences its functioning. Although biodiversity is now
known to affect ecosystem productivity1, 2, 3, 4, 5, 6, its effects on stability are debated6, 7, 8, 9,
10, 11, 12, 13. Here we present a long-term experimental field test of the diversity–stability
hypothesis. During a decade of data collection in an experiment that directly controlled
the number of perennial prairie species4, growing-season climate varied considerably,
causing year-to-year variation in abundances of plant species and in ecosystem
productivity. We found that greater numbers of plant species led to greater temporal
stability of ecosystem annual aboveground plant production. In particular, the decadal
temporal stability of the ecosystem, whether measured with intervals of two, five or ten
years, was significantly greater at higher plant diversity and tended to increase as plots
matured. Ecosystem stability was also positively dependent on root mass, which is a
measure of perenniating biomass. Temporal stability of the ecosystem increased with
diversity, despite a lower temporal stability of individual species, because of both
portfolio (statistical averaging) and overyielding effects. However, we found no evidence
of a covariance effect. Our results indicate that the reliable, efficient and sustainable
supply of some foods (for example, livestock fodder), biofuels and ecosystem services
can be enhanced by the use of biodiversity.