Potential Range Shifts Predict Long-Term Population Trends in Common Breeding Birds of the Czech Republic

Abstract

Breeding ranges of European bird species will probably shift as a result of the climate change in forthcoming decades. Although it is unclear whether these shifts will come true, one perceives the magnitude of these shifts as a measure of the intensity of the pressure of climate change on particular species. From this perspective, it is interesting to ask how these shifts relate to current species' population trends. For this purpose, we related the data on potential northward shifts of European breeding ranges based on projections of climate change to the long-term population trends for the period 1982-2011 of birds breeding in the Czech Republic. We predicted that the relationship between the magnitude of range shift and the population trend will vary according to the geographic position of species' distri- bution in relation to the position of the Czech Republic. The results indicated support for this prediction. After account- ing for the effects of various ecological traits like habitat association, migration and life history strategy, populations of the species with the largest shift declined, if the centre of their distribution was in the northern Europe, but increased if their distribution centre was on the south of the continent. These results suggest that the climate change is among the main factors causing recent changes in bird populations but its effects strongly depend not only on species sensitivity to these changes but also on geographic context.