What burned the forest? Wildfires, climate change and human activity in the Mesolithic – Neolithic transition in SE Iberian Peninsula

Climate variability such as higher or lower temperatures, changing precipitation patterns, shifts in plant communities and other climate-related changes have particularly affected areas with Mediterranean-type climates. A multi-proxy analysis including pollen, sedimentary charcoal, mineralogy and Summed Probability Distributions (SPD) of archaeological 14C dates, allowed the reconstruction of landscape change, geomorphological evolution and fire history at the Laguna de Villena, in the southeastern Iberian Peninsula, during the Mesolithic-Neolithic transition. The Villena paleolake was sensitive to Early Holocene and Middle Holocene regional climatic variability that included several arid phases (around 8.2 ka cal BP, 6.8 ka cal BP and 5.9 ka cal BP) according to geochemical and pollen data. During this period, landscape dynamics show the degradation of oak forests and expansion of pyrophytic pine forests and shrublands, as well as open spaces predominated by grasses. The charcoal record shows a decreasing trend of biomass burned from 8.5 ka cal BP onwards, although fire peaks occurred recurrently during the Early and Middle Holocene. The most intense phase of fire activity was experienced in the last millennia of the Early Holocene, with five fire episodes from 9.1 to 8.4 ka cal BP, coinciding with a phase of higher archaeological evidence in the area. A decrease in archaeological evidence coincides with a gap in fire episodes during the Early Holocene-Middle Holocene transition, suggesting an effect of the abrupt 8.2 ka cal BP event on human activity and on landscape dynamics. After 8.0 ka cal BP, lowerer biomass burned is explained by the configuration of a more open landscape due to the combination of climate (increasing aridity) and increasing human activities in the region. The mineralogical and palynological data highlighted the interaction between human activities, climate and fire dynamics. The sedimentary charcoal record evidenced how most of the fire peaks did not occur in the context of dry episodes, as often assumed, deriving on an anthropogenic explanation related to Early and Late Mesolithic burning practices during a phase of higher archaeological evidence in the Villena paleolake surroundings. Afterwards, combined agropastoral activities from the Early Neolithic onwards and increasing aridity during the Middle Holocene maintained the forest clearances, in the context of fire episodes characterised by decreased biomass burned. This study shows how Middle Holocene palaeoecological records reflect complex histories blending climate and anthropogenic processes that derived in major landscape changes explaining the origin of current landscapes.This research has received funding from the European Research Council (ERC) under the Horizon 2020 research and innovation programme (Grant agreement No. 683018) to JFLdP. Additional analyses on the pollen data sets have been produced in the context of the research project PID2020-113664RB-100 supported by the Spanish Ministry of Science and Innovation. JFLdP is additionally supported by the Plan Gen-T program (Ref. CIDEGENT-18/040) of the Generalitat Valenciana. CSG is currently supported by a Margarita Salas fellowship (ref. MARSALAS21-22) funded by the European Union-Next Generation EU, the Spanish Ministry of Universities and the University of Alicante. JR, IE and FB are members of the research group GAPS (2017 SGR 836). JR acknowledges postdoctoral fellowship support from the Spanish “Juan de la Cierva Incorporación (IJC2020)” program (MICINN, Spain). The Institut Català de Paleoecologia Humana I Evolució Social (IPHES-CERCA) has received financial support from the Spanish Ministry of Science and Innovation through the “María de Maeztu'' program for Units of Excellence (CEX2019-000945-M). LS is granted by the ICREA Academia Program

Impacts of Early Holocene environmental dynamics on open-air occupation patterns in the Western Mediterranean: insights from El Arenal de la Virgen (Alicante, Spain)

Open-air sites represent a fundamental proxy of the Early Holocene adaptive systems in the Iberian Peninsula. However, its research potential for the study of human–environmental interactions has been minimally explored. In this work, we present the results of an integrated research programme focused on open-area excavations at the Mesolithic site of Arenal de la Virgen (Alicante, Spain). Novel multi-scalar geoarchaeological and archaeo-stratigraphic studies, coupled with featured-based palaeobotanical analysis, were used to design an extensive radiocarbon dating programme and produce different Bayesian chronological models. Our results distinguish two different Mesolithic occupation phases, dating to 9.3–9.1 and 8.6–8.3k cal a bp respectively, consisting of combustion features and lithic scatters. The comparison of occupational dynamics with the nearby palaeoecological records of Salines and Villena indicated that both Mesolithic phases occurred under relatively stable environmental conditions. The second Mesolithic phase, however, ended during the onset of the 8.2k cal a bp climatic event, when sedimentation processes shifted from soil formation to accretion of aeolian sands. We demonstrate that the end of the Mesolithic occupations at Arenal de la Virgen coincides with the cessation of radiocarbon-dated activity in other open-air Postglacial sites in the central Mediterranean region of Iberia.This research is primarily part of a project that has received funding from the European Research Council (ERC) under the Horizon 2020 research and innovation programme (Grant agreement No. 683018) to JFLdP. Additional analyses on the pollen data sets have been produced in the context of the research project HAR2017-88503-P supported by the Spanish Ministry of Science and Innovation. JFLdP is additionally supported by the Plan Gen-T programme (Ref.CIDEGENT-18/040) from the Generalitat Valenciana. JRR is currently supported by a Margarita Salas fellowship (ref. MARSALAS21-22) at the University of Alicante, and AP-D is holder of a María Zambrano fellowship at the University of the Basque Country (UPV/EHU) both funded by the European Union-Next Gene and the Ministry of Universities (Government of Spain)

Palinología y restitución paleoecológica

A través de este escrito se pretende un acercamiento a las generalidades y aplicaciones de la ciencia palinológica. Así, partiendo de unas breves notas sobre las raíces de esta ciencia y su potencial aplicativo (sub-especialidades), se dan ejemplos de su utilidad para la reconstrucción del paleoambiente durante el Pleistoceno Superior (últimos 70.000 años), el actual Holoceno (últimos 10.000 años), así como de la evolución / extinción de especies vegetales durante este período de tiempo en el NE de la Península Ibérica.This paper is an approximation to the generalities and applications of the palynological science. Starting from some short notes of the roots of this science and its potential applications (sub-specialities), some examples of its utility to the reconstruction of the palaeoenvironment are shown. The Upper Pleistocene palaeoenvironment (last 70 kyrs), the Holocene (last 10 kyrs) and the evolution / extinction of vegetal species during these periods in the NE of the Iberian Peninsula are described in the paper