Spatial and temporal explorative analysis of sarcoptic mange in Alpine chamois (Rupicapra r. rupicapra)

The sarcoptic mange epizootic affecting chamois in the Dolomites Alps since 1995 has risen considerable concern in a management and conservation perspective, due to its strong impact on chamois and ibex populations. A remarkable amount of data has been collected by different wildlife research and management institutions, in order to analyze mange patterns and develop possible strategies to control the disease. The present study is aimed at providing a population-related figure of the spatial and temporal dynamics of clinical sarcoptic mange in alpine chamois, proposing an approach in which relevant basic concepts and parameters, as the definition of the epidemic front and its spreading speed, can be estimated and framed. The epidemic front was referred to the different mountain massifs, corresponding to well established management units of the chamois in the study area; moreover, the mange-related mortality peak at the massif level was used (in substitution of the index case/s) for temporal analysis of the disease spreading. Two speeds of the front have been estimated: a first raw average speed of about 3.38 km/year, and a second refined speed of 4.64 +/- 3.12 Km/year, more consistent to the variability in the field. The time series analysis showed that the impact of mange increases over the late winter months, reaching a peak in early spring. Our results strengthen the conclusions of previous studies, proposing a new frame to include other studies in progress on the Alpine chamois-Sarcoptes interactions