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  • Print publication year: 2005
  • Online publication date: September 2010

3 - Biodiversity evaluation methods



In general terms, biodiversity evaluation is the process of measuring the value (ideally quantitatively) of biodiversity components, such as the number of species present, the population of a species, a habitat (usually meaning a vegetation community) or the sum of all such components within a given area or site. Such evaluations may be carried out for a variety of reasons, e.g. for conservation priority setting, as part of Biodiversity Action Plan (BAP) development, for the selection of Protected Areas, for the identification of a site's features of conservation interest, as part of conservation objective setting, management planning and monitoring processes, and as part of an EIA or other statement to comply with planning procedures for a proposed development.

Evaluations may be carried out on various components of biodiversity (i.e. from genetic variation within species, to individual species, species assemblages, biotopes and biomes) and at a variety of scales, from specific sites, to counties, regions, countries, biogeographical areas (although these may be smaller than countries) and global. A wide range of potential biodiversity values may be considered, including intrinsic and socio-cultural values (Daily, 1997; Posey, 2000), and more direct socio-economic benefits (Daily, 1997), such as food, building resources, medicines and waste decomposition, etc. (Spellerberg & Hardes, 1992).

As this Handbook concentrates on site surveys and monitoring, rather than on regional- or national-scale studies, this chapter focuses on site evaluations.