Abstract: A large number of studies have now explicitly examined the relationship between species loss and ecosystem function. Analyzed by two independent groups, the results from such experiments show that reductions in species diversity generally result in reduced ecosystem functioning, across a wide range of ecosystems, diversity manipulations, and functions. This chapter analyzes both data sets in parallel to explain variation in the observed functional effects of biodiversity. This chapter concludes: 1) the functional effects of biodiversity differ among ecosystem types (but not between terrestrial and aquatic systems), 2) increases in species richness enhance community responses but negatively affect population responses, 3) stocks are more responsive than rates, 4) diversity reductions often reduce function at an adjacent trophic level, 5) increased biodiversity results in increased invasion resistance. This chapter also analyzes the shape of the relationship between biodiversity and function, and discuss consequences of different relationships.

Keywords: biodiversity, ecosystem function, meta-analysis, trophic levels, aquatic, terrestrial,