Species attributes are commonly used to infer impacts of environmental change on multiyear species trends, e.g. decadal changes in population size. However, by themselves attributes are of limited value in global change attribution since they do not measure the changing environment. A broader foundation for attributing species responses to global change may be achieved by complementing an attributes-based approach by one estimating the relationship between repeated measures of organismal and environmental changes over short time scales. To assess the benefit of this multiscale perspective, we investigate the recent impact of multiple environmental changes on European farmland birds, here focusing on climate change and land use change. We analyze more than 800 time series from 18 countries spanning the past two decades. Analysis of long-term population growth rates documents simultaneous responses that can be attributed to both climate change and land-use change, including long-term increases in populations of hot-dwelling species and declines in long-distance migrants and farmland specialists. In contrast, analysis of annual growth rates yield novel insights into the potential mechanisms driving long-term climate induced change. In particular, we find that birds are affected by winter, spring, and summer conditions depending on the distinct breeding phenology that corresponds to their migratory strategy. Birds in general benefit from higher temperatures or higher primary productivity early on or in the peak of the breeding season with the largest effect sizes observed in cooler parts of species' climatic ranges. Our results document the potential of combining time scales and integrating both species attributes and environmental variables for global change attribution. We suggest such an approach will be of general use when high-resolution time series are available in large-scale biodiversity surveys.

Biodiversity and Climate Research Centre Germany

BirdLife International Wellbrook Court Girton Road Cambridge CB3 0NA UK

British Trust for Ornithology The Nunnery Thetford Norfolk IP24 2PU UK

Center for Macroecology Evolution and Climate Department of Biology University of Copenhagen Universitetsparken 15 DK 2100 Copenhagen Denmark

Center for Macroecology Evolution and Climate Natural History Museum of Denmark University of Copenhagen Universitetsparken 15 DK 2100 Copenhagen Denmark

Department of Animal Ecology Institute for Wetland and Water Research Radboud University Nijmegen Toernooiveld 1 6500 GL Nijmegen The Netherlands

Department of Biological Sciences Goethe Universität Max von Laue Straße 9 60438 Frankfurt Germany

Department of Zoology and Laboratory of Ornithology Faculty of Science Palacký University Olomouc 17 listopadu 50 771 43 Olomouc Czech Republic

Dutch Centre for Field Ornithology P O Box 6521 6503 GA Nijmegen The Netherlands

European Bird Census Council P O Box 6521 6503 GA Nijmegen The Netherlands

Museum and Institute of Zoology Polish Academy of Sciences Wilcza 64 00 679 Warszawa Poland

Pan European Common Bird Monitoring Scheme Czech Society for Ornithology Na Bělidle 252 34 CZ 150 00 Prague 5 Czech Republic

Royal Society for the Protection of Birds The Lodge Sandy SG19 2DL UK

Sovon Dutch Centre for Field Ornithology P O Box 6521 6503 GA Nijmegen The Netherlands

Statistics Netherlands Post Office Box 24500 The Hague 2490 HA The Netherlands

Swiss Ornithological Institute Seerose 1 CH 6204 Sempach Switzerland

UMR7204 MNHN CNRS UPMC CRBPO CP51 55 Rue Buffon 75005 Paris France

Zoological Unit Finnish Museum of Natural History University of Helsinki P O Box 17 FI 00014 Helsinki Finland

References provided by Crossref.org

Farmland practices are driving bird population decline across Europe

Demographic variation in space and time: implications for conservation targeting

Long-term and large-scale multispecies dataset tracking population changes of common European breeding birds