1- Study species and area
The Alpine ibex is a mountain ungulate endemic to the European Alps, where it lives mostly in alpine meadows and rocky cliffs between 1,600 and 3,200 m asl (Brambilla et al. 2020b). The species recovered from near extinction during the last century (Biebach and Keller 2009) and thanks to reintroduction programs, is now present again on the entire Alpine arc with a population of around 55,000 individuals (Brambilla et al. 2020a). However, low genetic variability (Biebach and Keller 2010) and climate change (Brivio et al. 2019) may constitute a severe threat for the species in the future.
The Alpine ibex population in Gran Paradiso National Park ranged from ~2,600 to ~5,000 individuals over the last 65 years, with a fluctuating population dynamic, showing a recent strong decline after a population peak in the 1990’s (Jacobson et al. 2004, Mignatti et al. 2012). Ibex abundance in GPNP has been estimated with annual block counts performed by Park rangers every year since 1956 over the whole territory of the Park (with a total area of 720 km2). Block counts are performed by walking over established routes and from vantage points at the beginning of September, dividing the entire Park area into 38 sectors (or surveillance areas) that range from 5.24 to 37.21 km2each. Alpine ibex of both sexes show a rather high site fidelity (Parrini et al. 2003, Grignolio et al. 2004), and are assumed to remain in the same sector during the summer season.