The relationship between biodiversity and ecosystem functioning cannot be revealed by ecological
studies of communities that focus on the structure and behaviour of species and populations at a
location. What is needed in addition are studies that address the flux of energy and matter through theecosystem. The measures used may be different: for example, community studies may employ indices measuring aspects of biodiversity, whereas ecosystem studies utilize measures of standing crop, or flux of nutrients. Both are important in the evaluation of ecosystem services. Services directly linked to primary plant productivity, e.g. provisioning of food, are measured in biomass per unit area, or nutrient content per unit biomass, whereas cultural services may require a measure of complexity of biodiversity at a suitable scale, e.g. species richness in spatial units within the landscape (Srivastava and Vellend 2005). However, this is not to say that such measures are mutually exclusive. For example, the service of biological pest control is best estimated both by measures of biodiversity in terms of insect predator guilds, and their temporal relative abundance.