Alexandre Poiraud

Prehistoric impact on landscape and vegetation at high altitudes: An integrated palaeoecological and archaeological approach in the eastern Pyrenees (Perafita valley, Andorra)

Abstract A multi-proxy palaeoenvironmental study (pollen, non-pollen palynomorphs-NPP, macrocharcoal particles) of a small fen located in the Perafita valley (2240 m a.s.l, eastern Pyrenees, Andorra) was undertaken to trace prehistoric human activities related to woodland clearance and past land-uses at high altitudes. The results of this study constrained by 9 AMS radiocarbon measurements are combined with archaeological data and compared with similar research carried out at the same altitude in the adjacent Madriu valley (Andorra). The overall objectives of this article are, first, to formulate different chronological patterns and spatial land-use distribution at a micro-regional scale during prehistory and, second, to discuss different drivers of prehistoric occupation models in the eastern Pyrenean highlands. The palaeoecological study of the Planells de Perafita fen was performed at high temporal resolution, allowing us to focus on detailed prehistoric (mainly Mesolithic and Neolithic) and Bronze Age human activity. It demonstrates that the shaping of this cultural landscape is the result of a long-term land-use history, which began at the late Mesolithic/early Neolithic transition onwards (ca 6400–6100 cal BC). The existence of three main phases of “inter-valley” land-use variability has also been highlighted, thus testifying a complex and heterogeneous upland land-use model during the Neolithic and Bronze Age. These land-use variabilities between the two adjacent Andorran valleys provide the basis for a discussion of the way in which environmental constraints influenced prehistoric land-use spatial organisation and of how the interaction between environmental (including climatic parameters), socio-economic and cultural conditions affected the temporal and spatial dynamics of landscape shaping in the eastern Pyrenean highlands.

Velay and Mézenc Massif: Harsh Volcanic Highlands Around the Loire River Source

The Velay and its Vivarais rim combine many historical aspects of the Massif Central, from its Hercynian basement to the Tertiary tectonic and volcanic reactivations following the Pyrenean and Alpine orogeneses, from the Mesozoic and Tertiary planations to the Plio-Quaternary excavation of the valleys. While some of the landforms are nearly intact, erosion has played a big part in their shaping at all scales, interacting with the entrenchment of the hydrographic network, volcanism and local tectonics. As a result, a great diversity of environments and landscapes emerged, which also comprises traces of human activity, man having settled early in these beautiful, harsh highlands, which are famous for their quality pasture lands.