Implications of future climate- and land-change scenarios on grassland bird abundance and biodiversity in the Upper Missouri River Basin

Abstract

Over the past decades, numerous threats from climate- and land-use change to ecosystems have been identified. Grassland ecosystems are among the most endangered in the world and ongoing grassland declines in the Great Plains have been a major concern for avian biodiversity conservation. Threat mitigation may include biofuel cultivation, CO2 emissions reductions, and land conservation strategies. However, spatially explicit and species-specific population responses to future scenarios remain unknown. We show how future land-use and climate scenarios may affect abundance and biodiversity patterns for grassland birds in the Upper Missouri River Basin. We used georeferenced abundance records, 20 environmental predictors, and gradient boosting machines to create spatial abundance models for 24 grassland bird species. Models were scored to current conditions and seven future landcover/climate-change scenarios to spatially predict changes in bird abundance for 2050. Model accuracy varied by species (0.2% ≤ NRMSE ≤ 39.3%) but spatial predictions were highly accurate (.03 ≤ MAE ≤ 7.67). Mean abundances declined for eight species in at least one scenario, whereas abundances increased for 16 species. Multi-species change analyses identified areas of decreasing abundance, particularly in the southeast, whereas increasing were predicted at higher elevations to the west. Important predictors included temperature, forest distance, and elevation. Predicted abundances varied by species and geography. Abundances and distributions expanded for most species, but multi-species declines also occurred in many low-elevation areas. These models may improve understanding of species-specific responses to environmental change by identifying emerging areas of avian conservation concern.