Conservation priorities for birds and biodiversity: do East African Important Bird Areas represent species diversity in other terrestrial vertebrate groups?

An urgent question in biodiversity conservation is the extent to which priority areas for one well-known indicator group, like birds, "capture" species within other groups. The first tests of this question have indicated that capture is high. BirdLife International's "Important Bird Areas" (IBAs) work on this assumption. We test this for East African IBAs using databases on the distribution of all Afrotropical birds, mammals, snakes and amphibians, compiled at the Zoological Museum of the University of Copenhagen and mapped on a I-degree grid in the software WORLDMAP, We assess how well the IBAs capture terrestrial vertebrate species in the region, and find that absolute capture is high. Moreover, capture of regionally endemic and threatened species is also very high. We indicate those few important species and areas not covered by IBAs. However, the IBAs do not generally capture other groups significantly better than do random sets of areas covering the same extent. Further, systematically selected near-minimum sets of areas can capture more species in considerably less area. Nevertheless, these near-minimum sets take into account neither ecological processes (in particular, avian migration) nor actual land-use patterns. As data become available to incorporate these factors and other taxa into quantitative priority-setting techniques, IBAs may be able to be planned with added area-efficiency. For now, though,we suggest that IBAs are not only very effective on-the-ground priorities for the conservation of birds but they also represent the majority of other terrestrial vertebrate diversity.