Developing Pressure Indicators for Europe
Edited by Anil Markandya and Nick Dale
A. Markandya and N. Dale 1. THE LOSS OF BIODIVERSITY POLICY FIELD Biological diversity is deﬁned by the Convention of Biological Diversity (UNEP, 1992) 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. The importance of maintaining this diversity can be summed up as follows: (i) it is the basis for the stability and sustainability of natural ecosystems, (ii) it has a great range of potential and unexplored uses for humans, and (iii) it has existence values such as the amenity values of protected areas. The available evidence on species numbers and stress on ecosystems within Europe points to a decline of biodiversity within ecosystems (loss of habitats), within habitats (loss of species) and among species (decline of species abundance) (EEA, 1995). The causes of these declines are wide-ranging and complex, and this was reﬂected in the variety and number of proposed pressure indicators received in the ﬁrst PIP expert questionnaire.1 This list of proposed indicators covered a range of 38 ‘sub themes’ such as habitat fragmentation, agricultural practices, loss of genetic resources, pollution and urban development. For the second-round questionnaire the list was reduced from an original total of 258 proposed Loss of Biodiversity indicators to the 28 that were considered to be the most relevant and compatible with established sources of data. 2. RESULTS OF THE SECOND-ROUND...