A biodiversity intactness index

London

2005

45-90

Sonderdruck

40003299

The nations of the world have set themselves a target of reducing the rate of biodiversity loss by 2010. Here, we propose a
biodiversity intactness index (BII) for assessing progress towards this target that is simple and practical—but sensitive to
important factors that influence biodiversity status—and which satisfies the criteria for policy relevance set by the Convention on Biological Diversity. Application of the BII is demonstrated on a large region (4 3 106 km2) of southern Africa. The BII score in the year 2000 is about 84%: in other words, averaged across all plant and vertebrate species in the region, populations have declined to 84% of their presumed pre-modern levels. The taxonomic group with the greatest loss is mammals, at 71% of pre-modern levels, and the ecosystem type with the greatest loss is grassland, with 74% of its former populations remaining. During the 1990s, a population decline of 0.8% is estimated to have occurred.