Habitat-specific diversity in Central European birds

ABSTRACT Capsule Bird species richness was highest in forest and urban habitat types, lower in grassland and wetland, and lowest in cropland. Aims To investigate bird species richness patterns across different habitat types in Czechia, Central Europe. Methods Data from a national breeding bird monitoring scheme in Czechia, based on mapping of positions of individual birds along transects, were used to express the number of species in habitat polygons. Each polygon was represented by one of the eight habitat types (coniferous, mixed and deciduous forest, cropland, grassland and other open habitat types, urban habitat, and wetland) obtained by detailed country-wide vegetation mapping. Species richness of individual polygons was related to polygon habitat type and area by linear mixed effects models, taking the surrounding land cover composition into account. Results Bird species richness was highest in forest, as predicted, and respective forest habitat types did not differ from each other. Urban habitat hosted a similar number of species as forest. Species richness varied greatly between different open habitat types: cropland was the most species-poor of all the habitat types considered, whereas grassland and other types of open habitats hosted significantly more species, albeit fewer than forests, and did not differ from wetland. Slopes of species-area relationships in respective habitat types largely followed the patterns in species richness. Conclusions The observed patterns are partly driven by natural habitat characteristics, such as high vertical stratification of forest vegetation facilitating coexistence of a higher number of species. However, biogeography may also play a role, for example, and the relatively short time periods for colonization from Eastern European source areas may underpin lower bird species richness in grasslands. In addition, human interventions may drive the steep slope of the species-area relationship in forest, presumably caused by mosaic harvesting, as well as the shallow slope of this relationship in cropland and wetland, as a result of their intensive exploitation.