Influence of scale on conservation priority setting - a test on African mammals

Broad-scale priority regions for conservation can be identified using databases on species distribution through the application of site-selection algorithms. However, the influence of scale on large-scale priority setting is still unclear. Using a data set of all 939 sub-Saharan mammal species, we wanted to know if continental conservation priorities derived at the scales of 1degrees, 2degrees, 4degrees and 8degrees latitude-longitude grid cells are consistent. We tested whether (1) geographical location of minimum sets were nested across scale, (2) the selection sequence (priority) of areas within a minimum set were scale dependent, and (3) these coarse-scale priorities can act as a cost-effective shortcut for the identification of fine-scale priorities. We found that minimum sets at smaller scales were largely represented within minimum sets at larger scales, especially when flexibility was considered. However, the geographical location of the grid cells with highest priority in the minimum sets was only scale independent if ranked by number of endangered species, total species richness or rare quartile species richness, but surprisingly not by complementary species richness. Minimum sets at a 1degrees scale were generally identified within the areas of the 2degrees, 4degrees and 8degrees minimum sets. Therefore, coarse-scale priorities may provide a pragmatic basis for immediate assessment of priorities for conservation.