Patterns of relative abundance among large Carnivora in western Eurasia during the Plio-Pleistocene

Background: The present-day Carnivora metacommunity in western Eurasia is functionally impoverished of large hypercarnivores (animals that only eat vertebrate tissues). The interplay of climate change and interspecific competition in the decline of large hypercarnivores during the Plio-Pleistocene is not well understood. I estimated relative abundance trajectories for PlioPleistocene Canidae, Felidae, and Hyaenidae to infer competitive relationships within the families. I further examined how the family-level patterns influenced the proportion of hypercarnivores in the fossil metacommunity over time. Data: Presence/absence data of Carnivora (>7 kg) belonging to the families Canidae, Felidae, Hyaenidac, and Ursidae from 124 fossil localities. The fossil localities were sampled within six temporal intervals, spanning the Pliocene up to the beginning of the Late Pleistocene. The intervals track long-term changes in global and regional climate. The study area included Europe, Anatolia, Caucasus, and the Levant. Methods: Relative locality coverage (occupancy) within a sample was used as a proxy for relative abundance for individual taxa. For the community metrics, taxa were classified as hypercarnivores based on the morphology of the lower first molar. Conclusions: The results indicate differences in coexistence potential within the different families. Large felids, including both sabre-toothed and conical-toothed forms, tend to have broadly overlapping occupancy trajectories. The occupancy trajectories of large bone-cracking hyaenids overlap less extensively, being generally restricted to only one common taxon at a time. The occupancy trajectories in the Canidae seem to be almost independent of each other. At the community level, both the number of common taxa and the proportion of hypercarnivores among them increased from the Pliocene to the Early Pleistocene. This trend reversed again during the Middle Pleistocene. The most common Middle Pleistocene taxa mainly belonged to different families, emphasizing their ecological differences in seasonally cold environments.