Spiders of the Orsiera Rocciavrè Natural Park and Foresto Ravine Natural Reserve (NW Italy): a faunistic synthesis with data from the “Biodiversity Monitoring Project”

We present the inventory of the spiders (Arachnida, Araneae) inhabiting the Orsiera Rocciavrè Natural Park and the Foresto Ravine Natural Reserve (NW Italy). This work combines data from literature sources, unpublished material, and new samplings conducted between 2018 and 2019 as part of the “Biodiversity Monitoring Project”, supplemented by verified iNaturalist observations. In total, we report 212 species belonging to 128 genera and 32 families, including 12 new records for Piemonte. Linyphiidae Blackwall, 1859 and Gnaphosidae Banks, 1892 emerged as the most represented families, consistently with other similar Alpine parks. Most species exhibit Palearctic or European distributions, with a small proportion of endemics, including rare species such as Rhode testudinea Pesarini, 1984, for which new morphologic illustrations are provided. The new data presented here allowed us to study species richness and abundance along altitudinal gradients, revealing different patterns across the transects. Additionally, we conducted an indicator species analysis to identify key-species within elevational zonation. Beyond the faunistic contribution, we underline the importance of faunal inventories as a baseline for future studies on spider conservation ecology, especially within protected areas.