<P> The two main areas where the effect of biodiversity on ecosystem function have been studied are the relationship between diversity and productivity, and the relationship between diversity and community stability . More biologically diverse communities appear to be more productive (in terms of biomass production) than are less diverse communities, and they appear to be more stable in the face of perturbations . </P> <P> Also animals that inhabit an area may alter the surviving conditions by factors assimilated by climate . </P> <P> In order to understand the effects that changes in biodiversity will have on ecosystem functioning, it is important to define some terms . Biodiversity is not easily defined, but may be thought of as the number and / or evenness of genes, species, and ecosystems in a region . This definition includes genetic diversity, or the diversity of genes within a species, species diversity, or the diversity of species within a habitat or region, and ecosystem diversity, or the diversity of habitats within a region . </P> <P> Two things commonly measured in relation to changes in diversity are productivity and stability . Productivity is a measure of ecosystem function . It is generally measured by taking the total aboveground biomass of all plants in an area . Many assume that it can be used as a general indicator of ecosystem function and that total resource use and other indicators of ecosystem function are correlated with productivity . </P>

An increase in biodiversity of an ecosystem leads to an increase in its productivity