In-crop measures and fallows are most effective agri-environmental measures for the Eurasian skylark (Alauda arvensis) in Germany

The intensification of agricultural practices in all its facets has led to strong decrease of farmland bird populations. The Eurasian Skylark ( Alauda arvensis ), while still the most common bird of agricultural fields, has undergone a strong population and distribution decline in Western and Central Europe. Many different agri-environmental measures have been proposed to support the Eurasian skylark. However, few comparative experimental tests of AEMs have been conducted on commercial farms under real management conditions. Using a dataset from nine intensively managed farms across Germany that have implemented a broad set of AEMs, we aimed to identify the most effective measures as well as what factors influence their effectiveness. We find strong differences in the usage of measures. Legume plots and low-input cereal strips in maize both lead to at least 5x higher sightings compared to controls, while both annual fallows and farmland bird plots lead to 3-4x higher sightings. Flower-based measures are less effective (< 2x higher sightings), while some measures show no positive effect at all. While placing AEMs with a minimum distance of 100 m from wooded areas is strongly recommended, no other factor had a clear effect on the effectiveness of multiple AEMs