Aims: The Little Bustard often occurs in fragmented open landscapes in southwest Portugal, where agricultural fields are spaced with forest stands and shrublands. In these areas species abundances and distribution patterns are poorly known, and there is almost no information about the effects of human activities on the species. In this study we present the first results on the distribution and abundances, as well as macro-habitat modelling for Little Bustard displaying males.
Location: Site of Community Importance of Cabrela, an area included in the national list of sites ´Natura 2000`. Alto Alentejo, southwest Portugal.
Methods: Combining field data (displaying males distribution), GIS techniques and spatial analysis such as Ordinary Kriging, predictive models were computed for the occurrence of the Little Bustard during the breeding season.
Results: Results indicate a total of 72 displaying males and an average breeding density of 0.7 displaying males´ km-2. Logistic regressions suggest a slight tendency for the selection of the inner part of the larger patches of potential habitat. Variables related with soil constraints are likely to be important. The interpolated Ordinary Kriging models indicate a good agreement with the field data.
Conclusions: Ordinary Kriging models can be very helpful for modelling distributions in highly fragmented landscapes and as a tool for the management of the species habitat by potentially predicting the impacts derived from human actions at landscape level.
