Patterns in long-term changes of farmland bird populations in areas differing by agricultural management within an Eastern European country
Abstrakt
Capsule Differences in arable land-use intensity and land use changes in lowland and higher-altitude regions of the Czech Republic affected long-term population trends of farmland birds.Aims To describe changes in arable land-use intensity and land use in lowlands and at higher altitudes from 1982 to 2000 focusing on changes around 1990 when agricultural intensity declined and to test how these changes affected farmland bird populations.Methods Population trends for 24 species in lowlands (areas up to 300m a.s.l.) and at higher altitudes (300-600m a.s.l.) were calculated for time periods 1982-1990 and 1990-2000. Per hectare cereal yield represented a measure of arable land-use intensity and Corine Land Cover together with harvested area of cereals indicated land-use changes.
Annual population growth rate of particular bird species was related to agricultural indicators.Results In lowlands, arable land-use intensity declined after 1990, but this did not result in a lower decline of birds. At higher altitudes, arable land-use intensity did not change, but considerable areas of arable land were converted into pastures.
This change was related to population improvement for two species and deterioration for three species.Conclusion Trends in farmland bird populations in the Czech Republic were more likely driven by the arable land conversion to pastures rather than by changes in the arable land-use intensity.