Detecting the effects of diversity on measures of ecosystem function: experimental design, null models and empirical observations

Here we present a novel experimental approach to examine the relationship between diversity and ecosystem function. We develop four null predictive models, with which to differentiate between the 'sampling effect'– the chance inclusion of a highly productive species, and 'species complementarity'– the complementary use of resources by species that differ in their niche or resource use. We investigate the effects of manipulating species and functional richness on ecosystem function in a marine benthic system and using empirical data from our own experiments we illustrate the application of these models.