Agricultural intensification at local and landscape scales impairs farmland birds, but not skylarks (Alauda arvensis)

Abstract

Agricultural intensification constrains the occurrences of birds from local through landscape to regional scales. Here, we tested effects of landscape configuration (comparing regions with small vs. large field size, thereby contrasting former West and East Germany), local farming practice (organic vs. conventional) and within-field position (edge vs. centre) on the abundance and species richness of farmland birds in winter wheat fields, with particular reference to skylarks (Alauda arvensis). We surveyed birds by point counts during breeding season within nine pairs of organic and conventional managed winter wheat fields along the Western (ca. 3 ha fields) and Eastern (ca. 20 ha fields) side of the former Iron Curtain in central Germany (n = 18 pairs). Bird abundance and species richness within arable field centres was highest in the small organic fields of the West, whereas skylarks showed a strong preference for open field conditions provided by field centres in the larger fields in East Germany. In conclusion, overall bird abundance and richness within arable fields would benefit from reducing local intensification of farming practices and field size, whereas open-land species such as skylarks benefit from large fields.