Climate related niche segregation and resource partitioning of the ungulate faunas from the Middle Pleistocene succession (OIS 14-12) at the Caune de l'Arago (France)
Hypotheses related to climatic changes through time and habitdt preterences for Middle Pleistocene ungulates were tested. Rather than studying d single species, we use a community-based approach to reflect the community structure of the biome, the interspecific competition, and the resource availability in the habitat. We selected the Caune de 1'Arago assemblage that documents three main stratigraphic units correspon- ding either to cold and dry climate or to temperate and humid environments. Large samples of various herbivorous species (horse, reindeer, red deer, fallow deer, bison, musk ox, argali, and tahr) are available in all three units. We employ dental wear analy- ses as approach to infer the dietary niche of those ungulates. In comparing the three stratigraphic units, the interspecific variability in dental wear variables should reflect a climatic signal. The dental meso- and microwear signatures reflect a climatic signal according the changes in the three stratigraphic units, but also the interspecific variabil- ity. The importance of combined meso- and microwear analyses for the organisation and dynamics of ungulate communities during the Pleistocene is shown. A correlation between dietary habits and climatic changes is observed for horse, red deer, and bison. For all other ungulates, interspecific competition and resource partitioning may explain the diversity observed. Surprisingly, the more diverse is the community in term of species richness, the less diverse are the dietary traits. In all units, the overlap of the dietary signatures is very low, even if some share habitats or resources. This is interpret- ed as a coexistence of various strategies such as resource partitioning, grazing succes- sions, or niche segregation.