Global change pressures reduce reproductive performance and increase conservation reliance in a declining steppe raptor

Impacts attributed to global change, such as weather anomalies, land‐use changes and anthropogenic disturbances, often provoke demographic catastrophes mediated by the deterioration of reproductive output, especially in slow‐paced animals, that is top predators, often used as biological indicators of ecosystem networks.

In our study, we aimed to disentangle the bioclimatic variables affecting the breeding performance of a declining ground‐nesting raptor in southern Spain, the Montagu's harrier ( Circus pygargus ), a steppe‐specialist species highly affected by climate change and agricultural intensification. We also investigated how conservation measures implemented at nest scale modulated breeding outputs along with environmental variables. Furthermore, we assessed the long‐term viability of the population under different climatic and conservation scenarios.

Our analyses suggested that the breeding performance of the population is positively influenced by spring and autumn precipitation, habitat heterogeneity and some conservation measures; on the other hand, it is negatively influenced by human disturbance.

Our population viability analysis suggested that nest‐focused conservation measures—for example fences, unharvested buffers—may partially buffer the detrimental effects of weather anomalies. However, local conservation actions may not completely offset population decline in the long term.

Policy implications . Our analyses suggest that the species will remain dependent on intensive, multi‐scale conservation actions in the long term, a pattern likely shared by many pseudo‐steppe and farmland birds affected by global change. Beyond nest‐focused conservation actions, integrative broad‐scale policies aiming to mitigate climate change, habitat homogenization and intensification of agronomic systems are essential to ensure the self‐sustainability of the population. In this sense, reforming the Common Agricultural Policy is essential to integrate the conservation of steppe birds into agricultural planning.