Abstract
BACKGROUND: Climatic change is expected to lead to changes in species' geographical ranges. Adaptation strategies for biodiversity conservation require quantitative estimates of the magnitude, direction and rates of these potential changes. Such estimates are of greatest value when they are made for large ensembles of species and for extensive (sub-continental or continental) regions. METHODOLOGY/PRINCIPAL FINDINGS: For six climate scenarios for 2070-99 changes have been estimated for 431 European breeding bird species using models relating species' distributions in Europe to climate. Mean range centroid potentially shifted 258-882 km in a direction between 341 degrees (NNW) and 45 degrees (NE), depending upon the climate scenario considered. Potential future range extent averaged 72-89% of the present range, and overlapped the present range by an average of 31-53% of the extent of the present range. Even if potential range changes were realised, the average number of species breeding per 50x50 km grid square would decrease by 6.8-23.2%. Many species endemic or near-endemic to Europe have little or no overlap between their present and potential future ranges; such species face an enhanced extinction risk as a consequence of climatic change. CONCLUSIONS/SIGNIFICANCE: Although many human activities exert pressures upon wildlife, the magnitude of the potential impacts estimated for European breeding birds emphasises the importance of climatic change. The development of adaptation strategies for biodiversity conservation in the face of climatic change is an urgent need; such strategies must take into account quantitative evidence of potential climatic change impacts such as is presented here.