Biodiversity and ecosystem functioning across gradients in spatial scale

Biodiversity is critical for sustaining ecosystem functioning. Our inference, however, is based mainly on studies that have kept spatial scale constant and environmental heterogeneity to a minimum. We thus still know little about how the role of biodiversity changes with spatial scale and environmental heterogeneity. In this study we performed computer simulations to explore how the relationship between species richness and ecosystem functioning could be expected to change when local patches are aggregated into landscapes of increasing size. The expectations were tested in an experiment with five strains of E. coli under five different environmental conditions (defined by different sub-inhibitory antibiotics). We included all 31 possible strain combinations for each environment, yielding 155 unique local patch configurations and a total of 13860 patches with replication.