Potential impacts of climatic change on southern African birds of fynbos and grassland biodiversity hotspots

Aim To examine potential impacts of climatic change on bird species richness of the fynbos and grassland biomes, especially on species of conservation concern, and to consider implications for biodiversity conservation strategy. Location Southern Africa, defined for this study as South Africa, Lesotho and Swaziland. Methods Climate response surfaces were fitted to model relationships between recorded distributions and reporting rates of 94 species and current bioclimatic variables. These models were used to project species potential ranges and reporting rates for future climatic scenarios derived from three general circulation models for 30-year periods centred on 2025, 2055 and 2085. Results were summarized for species associated with each biome and examined in detail for 12 species of conservation concern. Results Species richness of fynbos and grassland bird assemblages will potentially decrease by an average of 3040% by 2085 as a result of projected climatic changes. The areas of greatest richness are projected to decrease in extent and to shift in both cases. Attainment of projected shifts is likely to be limited by extent of untransformed habitat. Most species of conservation concern are projected to decrease in range extent, some by > 60%, and to decrease in reporting rate even where they persist, impacts upon their populations thus being greater than might be inferred from decreases in range extent alone. Two species may no longer have any areas of suitable climatic space by 2055; both already appear to be declining rapidly. Main conclusions Species losses are likely to be widespread with most species projected to decrease in range extent. Loss of key species, such as pollinators, may have far-reaching implications for ecosystem function and composition. Conservation strategies, and identification of species of conservation concern, need to be informed by such results, notwithstanding the many uncertainties, because the certainties of climatic change make it essential that likely impacts not to be ignored.