Farmland practices are driving bird population decline across Europe

Stanislas Rigal, Vasilis Dakos, Hany Alonso, Ainārs Auniņš, Zoltán Benkő, Lluís Brotons, Tomasz Chodkiewicz, Przemysław Chylarecki, Elisabetta de Carli, Juan Carlos del Moral, Cristian Domşa, Virginia Escandell, Benoît Fontaine, Ruud Foppen, Richard Gregory, Sarah Harris, Sergi Herrando, Magne Husby, Christina Ieronymidou, Frédéric Jiguet, John Kennedy, Alena Klvaňová, Primož Kmecl, Lechosław Kuczyński, Petras Kurlavičius, John Atle Kålås, Aleksi Lehikoinen, Åke Lindström, Romain Lorrillière, Charlotte Moshøj, Renno Nellis, David Noble, Daniel Palm Eskildsen, Jean-Yves Paquet, Mathieu Pélissié, Clara Pladevall, Danae Portolou, Jiří Reif, Hans Schmid, Benjamin Seaman, Zoltán D. Szabo, Tibor Szép, Guido Tellini Florenzano, Norbert Teufelbauer, Sven Trautmann, Chris van Turnhout, Zdeněk Vermouzek, Thomas Vikstrøm, Petr Voříšek, Anne Weiserbs, Vincent Devictor

Declines in European bird populations are reported for decades but the direct effect of major anthropogenic pressures on such declines remains unquantified. Causal relationships between pressures and bird population responses are difficult to identify as pressures interact at different spatial scales and responses vary among species. Here, we uncover direct relationships between population time-series of 170 common bird species, monitored at more than 20,000 sites in 28 European countries, over 37 y, and four widespread anthropogenic pressures: agricultural intensification, change in forest cover, urbanisation and temperature change over the last decades. We quantify the influence of each pressure on population time-series and its importance relative to other pressures, and we identify traits of most affected species. We find that agricultural intensification, in particular pesticides and fertiliser use, is the main pressure for most bird population declines, especially for invertebrate feeders. Responses to changes in forest cover, urbanisation and temperature are more species-specific. Specifically, forest cover is associated with a positive effect and growing urbanisation with a negative effect on population dynamics, while temperature change has an effect on the dynamics of a large number of bird populations, the magnitude and direction of which depend on species' thermal preferences. Our results not only confirm the pervasive and strong effects of anthropogenic pressures on common breeding birds, but quantify the relative strength of these effects stressing the urgent need for transformative changes in the way of inhabiting the world in European countries, if bird populations shall have a chance of recovering.