Biogeographia – The Journal of Integrative Biogeography

This study investigates the north-eastern distributional limits of four short-winged endemic Orthoptera from the north-western Alps: Anonconotus ghilianii, A. pusillus, Epipodisma pedemontana, and Stenobothrus ursulae. Their spatial and altitudinal distributions were addressed within the Special Protection Area (SPA) IT1202020 “Mont Avic and Mont Emilius”, including the Mont Avic Natural Park, representing the north-eastern biogeographical margin for A. pusillus, E. pedemontana, and S. ursulae. In contrast, A. ghilianii occurs in the area as a small and isolated population of particular biogeographical interest. For comparison, two additional short-winged species with broader European ranges, Bohemanella frigida and Podisma pedestris, were also examined. A total of 258 records collected during 2020–2021 allowed the reconstruction of fine-scale distribution patterns within the study area. Most records (91.5%) were obtained above 1,950 m, highlighting the strong altitudinal affinity of these taxa. Higher upper altitudinal limits were documented for E. pedemontana (2,842 m a.s.l.) and S. ursulae (3,074 m), while the other two endemic species were confirmed at their upper elevational thresholds, with occurrences recorded in this study at 2,482 m for A. ghilianii and 2,827 m for A. pusillus. The spatial and altitudinal patterns observed are discussed in a broader Alpine context, and the distribution ranges of the four endemic species are interpreted in relation to adjacent mountainous sectors. The discussion of the genus Anonconotus also includes two additional species distributed adjacent to the study area, A. alpinus and A. occidentalis. These findings contribute to a better understanding of peripheral range dynamics, high-altitude biogeographical structuring, and the biogeographical history of endemic short-winged Orthoptera of the north-western Alps.