Predicted climate-driven bird distribution changes and forecasted conservation conflicts in a neotropical savanna.

Climate-change scenarios project significant temperature changes for most of South America. We studied the potential impacts of predicted climate-driven change on the distribution and conservation of 26 broad-range birds from South America Cerrado biome (a savanna that also encompass tracts of grasslands and forests). We used 12 temperature or precipitation-related bioclimatic variables, nine niche modeling techniques, three general circulation models, and two climate scenarios (for 2030, 2065, 2099) for each species to model distribution ranges. To reach a consensus scenario, we used an ensemble-forecasting approach to obtain an average distribution for each species at each time interval. We estimated the range extent and shift of each species. Changes in range size varied across species and according to habitat dependency; future predicted range extent was negatively correlated with current predicted range extent in all scenarios. Evolution of range size under full or null dispersal scenarios varied among species from a 5% increase to an 80% decrease. The mean expected range shifts under null and full-dispersal scenarios were 175 and 200 km, respectively (range 15-399 km), and the shift was usually toward southeastern Brazil. We predicted larger range contractions and longer range shifts for forest- and grassland-dependent species than for savanna-dependent birds. A negative correlation between current range extent and predicted range loss revealed that geographically restricted species may face stronger threat and become even rarer. The predicted southeasterly direction of range changes is cause for concern because ranges are predicted to shift to the most developed and populated region of Brazil. Also, southeastern Brazil is the least likely region to contain significant dispersal corridors, to allow expansion of Cerrado vegetation types, or to accommodate creation of new reserves.