Modelling habitat selection of Common Cranes Grus grus wintering in Portugal using multiple logistic regression

Predictive models of habitat suitability for the Common Crane Grus grus in a wintering area of southern Portugal were derived using logistic multiple regression and Geographic Information Systems. The study area was character ized by landscape variables and surveyed uniformly for the presence of cran es. The most important variables were distance to roosts, to open Helm Oak woods and to villages, and the occurrence of unpaved roads, shrubby vegetat ion, slope and orchards. Two models were built, the second having one varia ble fewer than the first. The selection of the best model was based on stat istical and biological criteria. Crane distribution was negatively related to: distance to open Helm Oak Quercus rotundifolia woods and roosts. Additi onally, unsuitable vegetation and orchard areas are avoided. In these areas movement is difficult, food availability is reduced and the risk of predat ion increased. We also found that villages and roads were avoided; disturba nce is a significant factor for this species. Some management guidelines; a re proposed for the area: (1) maintenance of open Helm Oak woodlands, (2) i ncentives to avoid the abandonment of traditional agriculture and pastoral use of the area, which would lead to an increase of shrubby vegetation area s, (3) preservation of suitable roosting places and (4) management of new p atches of forest and orchards.