Human adaptations to the reforestation of the South coast of the Bay of Biscay : 13,000-9000 radiocarbon years ago

The period from Bölling through Preboreal saw the oceanic Vasco‑Cantabrian region of northern Spain and extreme southwestern France pass from the rigorously cold conditions of Oldest Dryas with mainly open vegetation to more temperate conditions with increasingly wooded landscapes culminating in the dense, mixed deciduous, climax forests of the Atlantic period. As glaciers retreated and ultimately disappeared from the Picos de Europa, Cantabrian Cordillera and western Pyrenees, the sea level rose, eventually creating the estuaries and bays that would become so important to human survival during the Mesolithic in this region. Considering that this period only covered some four millennia, the environmental changes were dramatic and relatively abrupt. In contrast to general similarities in the vegetation records of Gascony, the Basque Country and Cantabria‑Asturias, there are significant differences in archaeofaunas across the Pleistocene‑Holocene transition between the two sides of the western Pyrenees: reindeer‑domination followed by red deer colonization in the north versus continuity of red deer domination in the south, always with ibex in steep, rocky habitats and an increase through time in woodland‑specialized species in both areas, as bison was extirpated and horse at least became much rarer. Against this backdrop, humans struggled to survive, as attested by the transformation of the Upper Magdalenian into the Azilian, with simplification of a continuity technological tradition but an apparently radical break in the symbol system that had supported the longstanding ideology of Tardiglacial hunting societies. The final rupture of the Magdalenian world came – not coincidentally – at the end of the Preboreal as the forests closed in on what now would become Mesolithic foragers, mainly concentrated along the Boreal shore.