Faunal dynamics during the Mid-Pleistocene revolution: What implications, if any, does this have for the appearance of the Acheulean in southwestern Europe?

New data from Europe, putting back the appearance of tools showing affinities or belonging to the Acheulean technocomplex to the late Early Pleistocene, open new questions about the onset of handaxe-making behaviour in the North Mediterranean region. This research aims to provide some clues to the debate by analysing at regional and local scale the main characteristics of the large mammalian fauna before and around the time of the first appearance of Large Cutting Tools in SW Europe. The database consists of 110 large mammal taxa from 58 local faunal assemblages (LFAs), ranging in age from about 1.6 to 0.5 Ma. Results obtained indicate that at the time of the Mid-Pleistocene Revolution the dynamics of large mammal fauna was mainly regulated by discrete dispersal events triggered by major climate changes. The environmental changes, removing keystone species and merging previously independently evolved taxa into new palaeo-communities, altered their internal equilibrium, giving rise to new inter-guild and intra-guild dynamics. The Lower local Stratigraphical Occurrence (LlSO) of various large mammals in key European Early and early Middle Pleistocene sites indicates that the change in taxonomical composition and structure of the fauna was a gradual process, caused by neither “turnover pulse” nor “migratory wave” events. Nonetheless, the evidence of multiple, discrete dispersals of large mammals may support the hypothesis that a few, poorly recorded dispersal events involving small human groups carrying a new technology led culturally different populations to coexist for a while in Europe during the late Early Pleistocene. The similarity degree among the ecological structure of LFAs, bearing or not evidence of human presence, shows on one hand that LFAs sharing a similar functional diversity were sparsely distributed over time, sometimes irrespectively of the age of sites and poorly affected by their geographic position. On the other, results obtained suggest that the relative amount of ecological groups related to the habitat preference and trophic behaviour of species, and the prey/predator relationships were among the factors that mainly controlled the human presence/absence at any site. Conversely, the presence of large predators does not seem to have had any particular relevance in controlling human dispersal and settlement. Based on available data, the hypothesis that the appearance of large cutting tools in Spain may more likely represent either the result of a local technological evolution or a different activity facies than a technological behaviour brought by newcomer populations seems to be the most parsimonious.