Bronze Age “pristinity”, Iron Age anthropization and Medieval intensification of human impact around Lake Montcortès (southern-central Pyrenees): a possible mid-elevation pattern and its significance for the definition of the Anthropocene

Abstract

The varved sediments of Lake Montcortès (central Pyrenees) have provided a continuous and well-dated high-resolution record of the last ca. 3000 years. Previous chronological and sedimentological studies of this record have furnished detailed paleoenvironmental reconstructions. However, palynological studies are only available for the last millennium, and the vegetation and the landscape around the lake had already been transformed by humans by this time. Therefore, the primeval vegetation of Montcortès and the history of its anthropogenic transformations remains unknown. This paper presents a palynological analysis of the interval between the Late Bronze Age (ca. 1100 BCE) and the Early Medieval period (820 CE), aimed at recording the preanthropic conditions, the anthropization onset and the further landscape transformations. During the Late Bronze Age (ca. 1100 BCE to 770 BCE), the vegetation did not show any evidence of human impact. The decisive anthropogenic transformation of the Montcortès catchment vegetation and landscape started at the beginning of the Iron Age (770 BCE) and continued during Roman and Medieval times in the form of recurrent burning, grazing, cultivation, silviculture, hemp retting and other human activities. Some intervals of lower human pressure were recorded, but the original vegetation never returned. The anthropization that took place during the Iron Age did not cause relevant changes in the sediment yield to the lake, but a significant limnological shift occurred, as manifested in the initiation of varve formation, a process that has been continuous until today. Climatic shifts seem to have played a secondary role in influencing catchment vegetation and landscape changes from the Iron Age onwards. These results contrast with previous inferences of low anthropogenic impact until the Medieval Period, at a regional level (central Pyrenees). The intensification of human pressure in Early Medieval times (580 CE onwards) has also been observed in Lake Montcortès, but the overall anthropization of its watershed had already commenced a couple of millennia before, at the beginning of the Iron Age. It could be interesting to verify whether the same pattern – i.e., Late Bronze “pristinity”, Iron Age anthropization and Early Medieval intensification of human pressure – may be a recurrent pattern for mid-elevation Pyrenean landscapes below the tree line. This pattern complicates the definition of the “Anthropocene”, as it adds a new dimension, i.e., elevational diachronism, to the anthropization of mountain ranges, in general.