Hedgerows diminish the value of meadows for grassland birds: Potential conflicts for agri-environment schemes

Hay meadows and hedgerows have been declining for decades in Western Europe. Conservation policies promote their protection but agri-environmental measures for both can be implemented in the same area, possibly generating loss of efficiency. We recorded grassland passerine abundance in 99 sampling plots distributed in hay meadow habitat. Sampling plots were located across a gradient of hedgerow density in a floodplain system. As expected, abundance and species richness increased with grassland area. More importantly, hedgerow density was negatively related to both response variables when grassland area was controlled for. This result is important for habitat management. Subsidizing agri-environmental measures for hedgerows and grassland is of interest for biodiversity, but incompatibility between measures may occur at the parcel scale if one landscape component (hedges) splits another component (meadows) down to the suitability threshold for grassland species. To optimize the payoffs of subsidies, it can be effective and efficient to manage agri-environmental schemes at the landscape scale.