Data from: 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 impacted by forest cover and fragmentation than migratory
species; and generalists and urban species would show weak responses.
Measures of total diversity did not peak at intermediate levels of forest
cover or fragmentation. Rarefaction-standardized species richness
decreased marginally and linearly with increasing forest cover and
increased non-linearly with productivity, whereas all measures increased
linearly with increasing fragmentation and landscape diversity. Forest and
open-habitat specialists responded approximately linearly to forest cover
and also weakly to habitat diversity, fragmentation and productivity.
Generalists and urban species responded weakly to the landscape variables,
but some groups responded non-linearly to productivity and marginally to
habitat diversity. Resident species were not consistently more sensitive
than migratory species to any of the landscape variables. These findings
are relevant to landscapes with relatively long histories of human
land-use, and they highlight that habitat loss, fragmentation and
habitat-type diversity must all be considered in land-use planning and
landscape modeling of avian communities.