Landscape evolution during the Middle and Late Pleistocene in the Madrid Basin (Spain): Vegetation dynamics and human activity in the Jarama-Manzanares rivers (Madrid) during the Pleistocene

The evolution of the landscape surrounding the rivers of the Madrid basin during the Middle Pleistocene is summarised in the present paper. Patterns of adaptation of human populations who settled on the riverbanks have been established in this area through geoarchaeological data recovered from associated deposits, mainly in the Manzanares and Jarama rivers. An exceptional paleoenvironmental record has been documented for the last 379,000 years in the sequences studied in the centre of the Iberian Peninsula. Pollen and non-pollen samples were studied in eight sequences obtained from different sedimentary environments of two terraces, one located in the Manzanares river (Complex Terrace of Butarque) and the other in the Jarama river (Complex Terrace of Arganda), both in Madrid (Spain). The findings show the constant presence of Pinus, sometimes as the prevailing species, and Juniperus as an element of the regional vegetation. The local vegetation is characterised by open Mediterranean forest and riverside woodlands, which together with the aquatic taxa demonstrates the presence of water. The occasional presence of deciduous forest taxa, probably related to riverside woodlands, suggest warmer conditions. Ubiquitous taxa prevail among the herbaceous strata. These types of plants do not require specific ecological conditions, but could suggest a certain degree of humidity and explain the low values of xeric taxa and sub-continental steppe grasslands. The development of nitrophilous taxa, associated with the presence of fauna, is consistent with the faunal remains recorded from the sites. However, the pollen record shows changes in the structure of the vegetation in all sequences (progressive increase in the tree component), as well as in the composition of the plant landscape (decrease of the Mediterranean taxa and increase of xeric and steppe grasslands), due to temperature and humidity rate related changes. Climatic oscillations are observed across the stratigraphic sequence, and discussed in light of the archaeological evidence for the human occupation of inland Iberia