ABSTRACT
Although the exact defi nition of biodiversity (or biological biodiversity) is the subject of considerable discussion, it is commonly defi ned in terms of genes, species and ecosystems, corresponding to three fundamental levels of biological organization. Some authorities also include a separate human element in their defi nitions: cultural diversity. e Convention on Biological Diversity defi nes biodiversity as ‘the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species and of ecosystems’. Genetic diversity includes the variation between individuals and between populations within a species. Species diversity refers to the diff erent types of animals, plants and other life-forms within a region. Ecosystem diversity means the variety of habitats found in an area. Much of this chapter is focused at the species level because this is where most research is concentrated. Some aspects of genetic and ecosystem diversity are dealt with in more detail elsewhere (see Chapters 4 and 13).
