<P> The diversity of species and genes in ecological communities affects the functioning of these communities . These ecological effects of biodiversity in turn are affected by both climate change through enhanced greenhouse gases, aerosols and loss of land cover, and biological diversity, causing a rapid loss of ecosystems and extinctions of species and local populations . The current rate of extinction is sometimes considered a mass extinction, with current species extinction rates on the order of 100 to 1000 times as high as in the past . </P> <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>

Describe the effect of the loss of biodiversity on productivity and health