Conflicts between lesser kestrel conservation and European agricultural policies as identified by habitat use analyses

European pseudo-steppes have suffered from extensive changes in agricultural practices during the past decades with the disappearance of field margins and fallow systems and the increase of biocide treatments. The negative effect on wildlife has led to the adoption by the European Union of policies more compatible with environmental conservation, but decisions about optimal land use are difficult to make because of lack of information. We studied habitat use by the Lesser Kestrel (Falco naumanni), a globally vulnerable species, in a Spanish pseudo-steppe (Los Monegros) where traditional agro-grazing systems are still being practiced,and we compared the results with those of another Spanish pseudo-steppe where modern and intensive agriculture has been implemented. We focused on the use by Lesser Kestrels of habitats subject to changes provoked by recent agricultural policies. Habitat availability was determined in a 3-km radius around 11 colonies, where 23 Lesser Kestrels were radio-tracked during the chick-rearing stage. Habitat selection was determined through compositional analysis. the rank of selected habitats was similar for all kestrels,considering both habitats surveyed and habitats where kestrels bunted. Kestrels selected field margins and cereal fields and rejected abandoned crops and scrubland. This selectivity seemed to be due to prey availability. In the intensively cultivated areas the kestrels selected similar habitats but used only small foraging patches and obtained smaller prey than in the traditional agro-grazing systems, probably because of the irregular distribution of prey resources as a result of the intensive biocide treatments. Consequently, in intensively cultivated habitats Lesser Kestrels had larger home ranges (63.65 km(2)) than in those with traditional systems (12.36 km(2)). These differences are reflected in the productivity and population trends of both populations. Thus, the best strategy for conserving the Lesser Kestrel seems to be the maintainance of traditional cereal cultures with low biocide treatments and numerous field margins. Both agricultural intensification and marginal land abandonment (with subsequent scrubland invasion) have detrimental consequences for this and probably for other pseudo-steppe species. Positive management steps can be encouraged by recent agro-environmental regulations such as the 2078/92 European Union Reglament, which favors the creation of programs in which agricultural practices accord with wildlife conservation.