Current population trends mirror forecasted changes in climatic suitability for Swedish breeding birds

Capsule Swedish breeding bird species that are predicted to experience a more suitable climate by 2050 are currently increasing in numbers. Aims To test, for a large set of breeding birds, if recent population trends mirror the changes in predicted climatic suitability across the Swedish distribution range, and to test if considering natal dispersal improves the fit of the predictive models. Methods Recent decadal population trends of 131 species of birds breeding in Sweden were compared to forecasted change in their future national distribution range by 2050, as simulated by suitability distribution models using climate and natal dispersal scenarios. Two other potential predictors of recent demographic trends are controlled for - namely habitat specialization and generation time. Results The 1998-2009 population trends were positively correlated with predicted changes in distribution range. Thus, forecasted changes in climatic suitability predict recent population trends. Accounting for the species-specific natal dispersal provided only a slightly better fit. Conclusion Recent climate change has affected the population size of Swedish breeding birds. Climatic suitability models can be an efficient tool for predicting the impacts of climate change on the abundance of birds.