Breeding bird species diversity across gradients of land use from forest to agriculture in Europe

Loss, fragmentation and decreasing quality of habitats have been proposed as major threats to biodiversity world-wide, but relatively little is known about biodiversity responses to multiple pressures, particularly at very large spatial scales. We evaluated the relative contributions of four landscape variables (habitat cover, diversity, fragmentation and productivity) in determining different components of avian diversity across Europe. We sampled breeding birds in multiple 1-km2 landscapes, from high forest cover to intensive agricultural land, in eight countries during 2001−02. We predicted that the total diversity would peak at intermediate levels of forest cover and fragmentation, and respond positively to increasing habitat diversity and productivity; forest and open-habitat specialists would show threshold conditions along gradients of forest cover and fragmentation, and respond positively to increasing habitat diversity and productivity; resident species would be more strongly i...