Large carnivores, dominant scavengers, and livestock management pressure shape carrion-associated vertebrates guilds in the Patagonian steppe

Carrion is a nutrient-rich yet unpredictable resource sustaining diverse vertebrate scavengers. We examined how environmental filters and species associations relate to scavenger guild structure under land-use change. In the Chilean Patagonian steppe, we deployed 70 ram carcasses across gradients of livestock management pressure, using a camera traps. At each carcass, we quantified species richness and a relative abundance index and applied Hill numbers ( q = 0, 1, 2) to assess diversity, relating patterns to environmental variables and to large carnivores (puma Puma concolor and culpeo fox Lycalopex culpaeus ) and dominant scavengers (Andean condor Vultur gryphus, grey fox L. griseus, kelp gull Larus dominicanus ). We recorded 41 vertebrate species using carrion (i.e., interacting directly with carcass tissue or fluids), representing the highest richness reported for steppe ecosystems. Guild composition varied spatially, with facultative scavengers (kelp gulls, grey foxes) numerically replacing condors at some sites. Presence of puma and culpeo fox was associated with more even and diverse assemblages, whereas Andean condor and grey fox were associated with increased unevenness. These patterns suggest that species identity and livestock management are important correlates of scavenger community structure. Our findings provide a regional baseline for understanding how livestock management and large carnivore occurrence relate to carrion-mediated ecosystem processes.