Bayesian modelling procedures for the evaluation of changes in wildlife habitat suitability: a case study of roe deer in the Italian Alps

# 1. Combining species protection with land management is a central concern for nature conservation but requires a collaborative, problem-solving approach. Existing procedures do not guarantee the participation of stakeholders in the decision-making process and, thus, do not necessarily support the development of acceptable management strategies. An analytical framework is required to assess the consequences of human land use for wildlife habitats, incorporating a quantitative structure for including stakeholder opinions. We provide such a framework. # 2. As an example, we used the procedure to evaluate the consequences of different building scenarios for the Turin 2006 Winter Olympic Games on potential roe deer Capreolus capreolus habitats. The analysis involved four steps: (i) three Bayesian models were developed to assess the suitability of six study areas for roe deer; (ii) the outcome of the models was converted into a habitat suitability index (HSI) for each study area; (iii) for each area, the building scenario chosen by the Olympic Games organizers was compared with alternative scenarios by means of HSI values; (iv) an HSI value was chosen as a benchmark to evaluate the ecological consequences of landscape changes. # 3. The building projects chosen by the Olympic Games organizers caused changes in HSI values in each study area, especially at one site. In three of the six study areas, the chosen projects minimized the loss of suitable roe deer habitat, while in the remaining areas the alternative building locations could have reduced the negative consequences of human activities. # 4. Synthesis and applications. A habitat suitablility index calculated with our procedure can be used to (i) compare different hypothetical land-use scenarios and make decisions about the location of human infrastructures to minimize habitat loss; and (ii) assess the consequences of human activities in relation to an ecological benchmark. The Bayesian approach provides a way to involve local stakeholders in the decision-making process, and thus is a useful tool for discussion of land-use policies. Our procedure could be applied to rare and common species and to assessing the consequences of all human activities involving reductions in natural habitat.