Effects of landscape-scale factors on goshawk Accipiter gentilis arrigonii distribution in Sardinia

Abstract

The Northern goshawk is a widespread and well-studied species, but few data concern the ecology of the corso-sardinian goshawk Accipiter gentilis arrigonii, which is endemic of Corsica and Sardinia. We studied the breeding habitat selection of the goshawk at landscape scale using MaxEnt, a presence-only modelling method. Working with 37 goshawk localizations, we built three single models, at 10, 30 and 50 km2 scale, and a mixed model, combining variables at different scales. The latter results the best one (AUC=0.866). The woodland variables are the most important factors (about 2/3 of percent contribution in the model) and they seem to act at the minimum scale (10 km2): the woodland area (>200 m from the forest edge) is the most important variable and it has a positive effect, as well as the broadleaved forest and the coniferous forest, even if the latter only if present in small amount (<0.02 km2). At broader scales (30 and 50 km2) the goshawk seems to be sensitive to human disturbance avoiding plains (where there is the highest level of human activity) and urban areas, including small and sparse settlements. The surface of open land <200 m from forest edge, which is a goshawk hunting habitat, has a low weight but a positive effect at scale of 50 km2.