Habitat associations of a raptor community in a mosaic landscape of Central Spain under urban development.

摘要

The effects of urban sprawl and the associated road network on patterns of land use by diurnal raptors were assessed in a extent mosaic landscape of Sierra de Guadarrama subjected to exurban development (Madrid province; Central Spain), within the buffer area of a planned national park. During three consecutive years, the sightings of raptors per 0.25 km2 were analyzed to identify their habitat preferences according to several vegetation types, urban cover and length of paved roads. Species richness increased with the amount of deciduous forests of Pyrenean oak Quercus pyrenaica and parklands of Narrow-leaved Ash Fraxinus angustifolia in lowland areas, while it decreased with cover of urban/suburban areas. Analyzing the three most abundant species separately, urban development had a negative influence on the Common Buzzard Buteo buteo and the Black Kite Milvus migrans, although positively affected the Booted Eagle Hieraaetus pennatus, probably through an increase in the availability of its potential prey within urban areas. This study did not find a negative influence of the road network, either considering total species richness or the three most abundant species separately. The current levels of urban development diminished the suitability of the study area for the raptor community overall (though particular species can be favoured), notably when residential sprawls are established over ash parklands traditionally devoted to cattle grazing.