The benefits of being stressed

Abstract

Nearly 30 years ago, J.P. Grime provided evidence that plant species richness showed a hump-backed or unimodal relationship with total plant biomass or productivity, and that plant diversity was maximized by stress or disturbance factors that promoted intermediate levels of standing biomass. Although the mechanistic basis behind this relationship has subsequently been hotly debated, unimodal relationships between plant diversity and stress or disturbance, particularly in grasslands, have been recurrent themes in the plant ecology literature. Evidence for comparable hump-backed relationships for consumer organisms has, however, remained rather more elusive. Furthermore, remarkably little is known about whether such a relationship might exist for belowground organisms, although the soil biota includes the majority of the Earth's terrestrial species of organisms and is responsible for major ecosystem functions, such as decomposition and nutrient mineralization.