This project is a case study designed to identify the dynamics of local subsistence adaptations to the climate-induced environmental transformation of the Pleistocene-Holocene transition. Set in the Mediterranean region of southeast Spain, it includes two systematic archaeological surveys and the geochemical analysis of stone tools collected during the past decade of archaeological research in the study area. The surveys sample the sources of raw material, from which stone tools were made, along three natural corridors connecting major ecological zones from the Mediterranean coast through the mountains to Spain's interior plain and establish the archaeological presence or absence of late Pleistocene human groups where the natural corridors intersect the interior plain. Each survey is the first of its kind in the region. Two previous pilot projects leading to the current dissertation project have helped pioneer the use of Proton Induced X-ray Emission (PIXE) analysis to produce quantifiable geochemical signatures from stone tools and the raw material used to make them. Geochemical signatures are used here to link archaeological sites on a chronological scale, to track the movement and land-use patterns of human groups, and to establish the economic territories of groups with access to specific raw material sources.
The Pleistocene-Holocene transition is the only previous global environmental transformation confronted by modern humans - making it the best available analog for understanding potential human reactions to future climate change. However, late Pleistocene archaeological records in most of Europe are dominated by the Last Glacial Maximum (LGM), which forced major shifts in demography. Human populations abandoned continental Europe west of the Ural Mountains at the LGM and packed into defined refugium areas. As the ice receded, and the Pleistocene began its transition to the Holocene climate regimes in which we now live, refugia populations dispersed outward and recolonized Europe. Mediterranean Spain was an exception, where the interval between late Pleistocene and early Holocene remained a relative continuum. For example, no territory in the study area was excluded from the subsistence base by glaciation. Changes in land-use can be considered responses to the ecological aspects of climate transformation and not simply a response to newly available land. As a result, Mediterranean Spain is a natural venue for studying the ecodynamics of human adaptation to the Pleistocene-Holocene transition.
Resilience in subsistence adaptations is a function of access to sufficient resources. Viewed from this perspective, late Pleistocene and early Holocene hunter-gatherer subsistence economies balanced a set of variables roughly analogous to those of local subsistence economies in climate-sensitive developing nations today. Exponential changes in population density between the Holocene and now redefine what is sufficient, as differences in technology modify the degree and pathways of access, but neither alters the fundamental relationships. An archaeological perspective allows a better understanding of ultimate, rather than proximate, causes of social and ecological system resilience - and that is the broader impact of this research. It recognizes global climate transformation as a challenge that local human groups have previously confronted, and it creates a conceptual framework within which to examine the decision-making processes and that allowed them to adapt in a world of unprecedented change.
