A wolf habitat suitability prediction study in Valais (Switzerland)

In recent years, the European wolf ( Canis lupus) population has expanded its southern range from the Italian Peninsula to the Maritime Alps (Italy and France) and to Piemonte (Italy); establishing small sub-populations. Hence re-colonisation of the Swiss Alps is now likely to occur. In 1995–1996 the wolf reached the southern part of Switzerland (Canton of Valais) from where he got extinct 150 years ago. Actual conflicts of interests between livestock breeders, local political authorities and nature conservation parties, as well as federal authorities defending the protected status of wolf, require serious management investigations. In order to check wolf habitat suitability of an alpine landscape, like the Valais, subjected to dynamic landscape–ecology processes since the extinction of wolf, we present herein an application of a predictive wolf habitat model, using a stochastic model involving logistic regression. As no data were available in the Canton of Valais, the regression coefficients for the retained variables such as urban area, population density, arable land, minimal altitude, northwest exposure and wild ungulate diversity index, were derived from data collected in the northern Apennine (Northern Italy), where habitat variables were related to data of wolf presence. The selection of the parameters for the Canton of Valais has been performed in respect of their predictive power, as well as their availability and geo-morphological importance for the alpine landscape under consideration. Using the geographic information system (GIS), the simulation pointed out that 19% (1142 km ²) of the total grid surface (5821 km ²) are suitable for wolf presence. Moreover, it reveals that especially areas at lower altitudes (minimum altitude<800–900 m a.s.l.), due to the high anthropic activity, and areas at high altitudes (minimum altitude>1800–2000 m a.s.l.), due to lack of prey and severe geo-morphological conditions, present a reduced habitat suitability. The geomorphological and demographic situation of the alpine area lead to a wolf habitat of a partially fragmented and linear aspect, affecting overall habitat suitability. The strengths of the application is not only the visualisation of the present habitat quality of an alpine landscape re-colonised by wolves, but also that it allows to make investigations in order to manage the different conflicts of interest.