Raptor distribution in relation to landscape composition in semi-arid Mediterranean habitats.
Abstract
Breeding sites of raptors were studied in relation to land-use and edge habitat using 2 different scales in semi-arid Mediterranean landscapes in south-eastern Spain during 1991. The main tree species was Pinus halepensis with Quercus rotundifolia, Pinus pinaster and P. nigra being less common. Habitat relationships were analysed using generalized linear models. Four tree nesting species were studied (Hieraaetus pennatus, Circaetus gallicus, Buteo buteo and Accipiter gentilis), each with different breeding ranges but of a similar size. The proportion of forest cover at a small scale was the best predictor for all species. At a larger scale, the proportion of forest cover was also a good predictor, and the amount of edge habitat between forest and extensive agriculture was a very good predictor of H. pennata and C. gallicus densities. Models for sedentary species of raptor were similar using both scales whereas trans-Saharan migrant raptors seemed to be more sensitive to larger landscape features that included longer edges between forest and extensive agriculture. Habitat mosaics created by forestry and traditional farming were especially important for these Mediterranean raptors. It is suggested that strengthening of the Agri-environmental Regulation (2078/92) may be necessary to compensate for agricultural intensification proposals promoted under the Common Agricultural Policy.