Biodiversity is exposed to increasing pressure by climate and land use changes. But how are species responding to these pressures and which pressure is more dominant remain controversial questions. A recent collaborative study including 28 European countries assesses, for the first time, how 170 bird species have responded to major human induced pressures at a continental scale. This is the most comprehensive dataset ever assembled measuring the relative contribution of several metrics of climate and land use changes on bird populations, consisting of 170 species monitored across Europe at 20,000 sites over 37 years.

The detrimental effect of agriculture intensification on avian biodiversity at the European scale is one of the major findings of the study. The increase in pesticides and fertilizer have led to the decline of many bird populations, and even more to birds eating insects. The other strength of the findings lies in the methodology used. The results do not simply quantify correlations. The analytical design reveals causal responses of birds to global change drivers. Pressures and bird abundances have been monitored simultaneously in space and time as in an experimental setting.

According to the authors, this study calls for urgent decisions and accelerations of strict control and regulations of farmland practices. The results leave no doubts on the detrimental effect of pesticides and fertilizers on many bird species. This is not a local problem, the detrimental effects scales up to the whole Europe.