Ecology of large ungulates in the northeastern Iberian Peninsula during the Upper Palaeolithic through stable isotopes and tooth wear analysis

The northeastern Iberian Peninsula acted as a refuge zone during the Late Pleistocene where the persistence of terrestrial ecosystems could provide hunter-gatherers with large prey, mainly horse (Equus ferus) and red deer (Cervus elaphus). Isotopic (δ¹³C, δ¹⁸O, δ¹⁵N) and dental wear (mesowear and microwear) analyses have been applied on the remains of both species from the archaeological sites of Arbreda and Bora Gran at Serinyà (Girona), where evidence of human occupation from the Mousterian to the Magdalenian has been attested. The incremental enamel analysis on horse teeth revealed seasonal variation in carbonate δ¹⁸O but no detectable change in carbonate δ¹³C values, reflecting a rather stable diet and habitat over the year. Nevertheless, higher inter-individual than intra-individual contrast in carbonate δ¹³C indicate different environmental conditions from one individual to another for each stratigraphic unit. In red deer teeth, seasonal signals in enamel carbonate δ¹³C and δ¹⁸O demonstrated mirrored trends. Further, red deer show higher δ¹³C values than those of horses, both in enamel carbonate and bone collagen, as well as higher variability in mesowear and microwear scores, reflecting a mixed-feeding habit. Despite a strong grazing signal in mesowear and microwear, the lower δ¹³C values for horses suggest a higher dependence on relatively more humid habitats than red deer, which likely foraged in dryer environments with xeric plants during winter. These differences in ecological partitioning are particularly well illustrated in distinct collagen δ¹³C and δ¹⁵N values during the harsh climatic conditions of the Final Gravettian coeval to the GS-3 or Last Glacial Maximum. The capacity of red deer to adapt to fluctuating environmental conditions contrasts with the niche persistence of horse allowed by the availability of mosaic habitat.