Rock Partridge Alectoris graeca saxatilis occurence in pastoral habitats. The Val Troncea Natural Park case of study.

In this paper we present the preliminary results of a long term project concerning sustainable strategies for the conservation of alpine grazing-land biodiversity and multifunctional use in the Val Troncea Regional Park (Piedmont, Italy). In the study area the occurrence of Rock Partridge Alectoris graeca saxatilis, monitored since the late '80, was used to study the habitat selection and how traditional agro-pastoral practices and vegetation dynamics affect it. In the project, cost-effective pastoral practices such as night camping and the placement of salt blocks to attract the livestock in the more marginal areas are proposed to improve habitat heterogeneity and diversity where they are decreasing due to under-exploitation of grasslands. During summer 2010 we sampled 342 cells of a 150x150 m grid extended all over Val Troncea Park. Inside each cell we gathered data about woody and herbaceous vegetation composition, synecology, forage quality, species richness, canopy structureof herbaceous and shrub layers, grazing management, and topography (exposure, slope, altitude,solar radiation, extracted from DTM). We found the signs of Rock Partridge presence in 174/342 cells. The species presence was positively affected by thermic condition areas, where mainly Festuca gr. ovinaand other xerophilous vegetation types occurred. Partridge presence was also significantly associated to intermediate mesotrophic condition vegetation (Festuca gr. rubra). Canonical correlation analysis showed that high-altitude vegetations types and tall eutrophic swards were generally avoided. Conversely, partridge presence was not significantly correlated to oligotrophic (e.g. Carex sempervirens) and woody vegetation. Nevertheless Juniperus nana shrublands tended to be selected, as dynamically related to thermic vegetations types.