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The Black Death is the most reknown pandemic in human history, believed by many to have killed half of Europe's population. However, despite the advances in ancient DNA research that allowed for the successful identification of the pandemic's causative agent (bacterium Yersinia pestis), our knowledge of the Black Death is still limited, based primarily on medieval texts available for single areas of Western Europe. In our study we remedy this situation and we focus in particular on the scale of the Black Death mortality. We collected data on landscape change from 261 coring sites (lakes and wetlands) located in 19 European countries. We used two independent methods of analysis to evaluate whether the changes we see in the landscape at the time of the Black Death agree with the hypothesis that half of the population died within a single year in each of the 21 regions we studied. We discovered that while the Black Death had devastating impact in some regions, it had negligible or no impact in others. The inter-regional differences in the Black Death mortality across Europe demonstrate the significance of cultural, ecological, economic and climatic factors that mediate the dissemination and impact of the disease. The complex interplay of these factors, along with the identification of the pathogen that caused disease outbreaks, should be the focus of future research on historical pandemics. more...

Human impact on western Mediterranean mountains is gaining more attention, as they harbour a rich plant diversity threatened by global change. This paper presents an analysis of two pollen records from both sides of Sierra Nevada, the prime plant-diversity centre of the Mediterranean, spanning the last 5400 years. The analysis sought to answer the following key questions: When did natural systems transform to cultural landscapes? What was the intensity and extent of alterations driven by the diverse civilizations? A compilation of archaeological and paleaeoclimatic data supported this analysis, as well as a multi-proxy palaeoecological study using pollen, non-pollen palynomorphs and microcharcoal, searching for the imprint that diverse societies left on these mountains. Results suggest that human influences started earlier than expected, with a strong impact on forest cover, oriented more towards crops on the southern face and towards livestock on the northern one, whereas mining and metallurgy were initial key drivers of population dynamics. Irrigation has supported farming since at least the Islamic period. More recent anthropogenic control and land-use management have allowed a further spread of the tree cover. Proper conservation strategies need long-term perspectives, including palaeoecological studies. The preservation of traditional human activities like grazing, high-elevation cropping or irrigation systems become essential to maintain current biodiversity., Departamento de Botánica, Universidad de Granada, España, Instituto de Historia, Consejo Superior de Investigaciones Científicas, España, Departamento de Biología Vegetal I, Universidad Complutense de Madrid, España, Departamento de Geografía, Urbanismo y Ordenación del Territorio, Universidad de Cantabria, Estación paleontológica Valle del río Fardes, Instituto Geológico y Minero de España, España more...

This work presents the anthracological and archeopalynological results obtained within the project AGRIWESTMED (ERC AdG 230561), which has involved a comprehensive retrieval of archeobiological remains based on a systematic sampling strategy, beyond the recovery of the usual archeological materials. These surveys were conducted on three sites located in the North of Morocco: the cave of Kaf Taht-el-Ghar, 8 km southeast from Tetuan, and two caves within the El Khil complex, close to Tanger. Both plant micro- and macro-remains (charred wood) were studied through palynological and anthracological analyses, respectively., Our goal was to assess the vegetation composition of the area as well as the impact of human activities on the landscape. In Kaf Taht-el-Ghar the dynamics of vegetation and land use is recorded over the Paleolithic, Epipaleolithic, Neolithic and Historic times. Clear changes such as the demise of ancient Paleolithic pine and juniper woods during the Epipaleolithic and the subsequent spread of grasslands are shown. Other conifers like Abies pinsapo, Cedrus atlantica and Taxus baccata also disappeared from the pollen and charred wood records. In the palynological study, cereal and broad beans (Vicia faba) are already detected in the Early Neolithic, as well as a lowering of grazing pressure. Both cereal and broad beans, along with the development of grazing activities are also documented around El Khil caves since the Early Neolithic. Throughout the whole pollen and anthracological sequences a progressive retreat of the tree cover and an extensive spread of grasslands could be set as the main features of the vegetation dynamics in this area., This study was funded by: -European Research Council Advanced Grant AGRIWESTMED (ERC AdG 230561). MRA; DAS; JALS and FAS are team members of the Research Projects listed below. While drafting this manuscript MRA and DAS have received financial support by c) and a) research projects, respectively. a) Spanish government, State R&D Program Oriented to the Challenges of the Society, MED-REFUGIA Research Project (RTI2018-101714-B-I00). b) Andalusian Plan for Research, Development and Innovation: OROMEDREFUGIA Research Project (P18-RT-4963). c) ERDF Operational Programme in Andalusia (EU regional programme): RELIC-FLORA 2 Research Project (B-RNM-404-UGR18). more...

Paleo-wetlands have fragmented in archaeological times associated with human stressors. We present an interdisciplinary analysis of a past temporary paleo-wetland located at an important junction between the valleys of the Rivers Guadalquivir and Guadalimar in the province of Jaén (Eastern Andalusia, Spain). We applied a high-resolution protocol to identify the paleo-wetland used for ritual purposes during the Iron Age. Based on archaeological excavations and analyses (soil micromorphology, pollen and phytoliths analyses, optically stimulated luminescence [OSL] datings, and other techniques), we found a palaeosoil formed in a wetland environment active during the Late Holocene, dating back to the 9th century AD., We are thankful for the support received from the “Ramón y Cajal” Sub-programme (RYC-2017-22122) funded by Ministry of Science and Innovation of Spain (MCIN/AEI /10.13039/501100011033) and by the European Union (European Social Fund. FSE) to CRG; and from the Juan de la Cierva-Formación Subprogramme (FJC2019-041335-I) funded by the Ministry of Science and Innovation of Spain (MCIN/AEI/ 10.13039/501100011033) and by the European Union (NextGenerationEU/PRTR) to MG-R;andthefollowing Research Projects: P20-00301/UJA; RTI2018-101714-BI00; P18-RT-4963; B-RNM-404-UGR18. more...

Current knowledge of climate change effects on forest ecology and species conservation should be linked to understanding of the past-time. Abies pinsapo forests constitute a model of an endangered ecosystem, highly vulnerable to ongoing warming, whose populations have been declining for centuries, while the drivers of this local depletion trend remain poorly understood. We hypothesized that long-term disturbances, both human- and natural-induced, have shaped A. pinsapo forests, contributing to these decline processes. Until today, studies using fossil pollen record to identify past climate impacts and land-use changes on A. pinsapo populations have not been done. Here, we investigate forests’ dynamics since the late Holocene (1180 cal. AD to present) in Southern Iberian Peninsula from a fossil pollen record by comparing the results obtained with climate fluctuations and land-uses changes. The pollen sequence shows a phase of stability during the Islamic Period (~1180–1400 cal. AD; ‘Medieval Climate Anomaly’), followed by increasing degradation at Christian Period concurrent with ‘Little Ice Age’ (LIA) (ca. 1487–1530 cal. AD). The Modern Period (1530–1800 cal. AD; LIA) is linked to intensive forest management, related to the naval industry. Afterwards, a progressive reduction is recorded during the Contemporary Age period (‘Industrial Period’) until ‘Recent Warming’. In short, historical severe forest management coupled with increasing aridity since LIA appear to influence A. pinsapo forest current species composition and poor structural diversity. These disturbances might be limiting the resilience of A. pinsapo forests under a climate change scenario. A selected forest management could promote a more complex forest structure. more...

Alba-Sanchez, F., Abel-Schaad, D., Lopez-Saez, J.A., Sabariego Ruiz, S., Perez-Diaz, S., Gonzalez-Hernandez, A. 2018. Paleobiogeography of Abies spp. and Cedrus atlantica in the Western Mediterranean (Iberian Peninsula and Morocco). Ecosistemas 27(1): 26-37. Doi.: 10.7818/ECOS.1441 The Mediterranean species included in the genus Abies, and Cedrus atlantica show very limited distribution ranges at present. In this work, we outline the origin and migratory routes followed by Abies pinsapo, A. marocana, A. tazaotana and Cedrus atlantica, from the beginning of the Tertiary to the present, as well as the likely causes which have led their populations to their current state of isolation and danger of extinction. Abies and Cedrus would have reached the Western Mediterranean along with other elements of the arctotertiary flora between the Middle Eocene (45 Ma) and the Oligocene (30 Ma). They subsequently underwent speciation processes until relatively recent times, among which the opening of the Strait of Gibraltar (5.33 Ma) would have played an essential role. Mediterranean firs and cedars would have stayed in Southeastern Iberian and North African mountainous refugia during Quaternary glaciations-deglaciations. Despite a noticeable expansion and altitudinal migration in the Mid-Holocene thermal optimum, these species have experienced a further remarkable decline, as a result of the increasing aridity and pressure of human activities. The development of the most appropriate conservation strategies requires the best information on the response of these species to diverse disturbances, thus the knowledge on their temporal evolution becomes essential. The fossil record, both macrorests and pollen, contributes, along with diverse genetic studies, to assessing their resilience and vulnerability. more...

The use of fire and, consequently, its severity and incidence on the environment, has grown steadily during the last millennia throughout the Mediterranean. This issue can be assessed in several mountain ranges of central Iberia where changes in the management policy on anthropic activities and exploitation of high-mountain environments have promoted a remarkable increase on fire frequency. Our research focuses on fire dynamics throughout the last three thousand years from three peat bog charcoal records of the Gredos range (central Iberia). Our aim is to reconstruct past fire regimes according to forest vegetation typology (Castanea sativa, Pinus pinaster, P. sylvestris). Charcoal influx shows low values between 3140 and 1800 cal. yr BP when forests were relatively dense both in high and mid-mountain areas. Fire appeared synchronous between 1800 and 1700 cal. yr BP for Lanzahita and Serranillos and around 1400-1240 cal. yr BP for the three sites suggesting anthropogenic fire control between the Late Roman and the Visigothic periods that can be related to the cultivation of olive trees in the valleys and a greater human impact in high-mountain areas. By contrast, during the Muslim period (1240-850 cal. yr BP) fire dynamics becomes asynchronous. Later, fires turn again coeval in the Gredos range during the Christian period (850-500 cal. yr BP) and can be also correlated with drought phases during the Late Medieval Warm Episode. In short, our study demonstrates that fire activity has been enormously variable during the late Holocene in response to both short- and long-term regional and global climate, vegetation dynamics and land use changes. more...

A new record from a long sediment core (S3) in Navamuño (1505 m asl, western Iberian Central System) provides the reconstruction of the vegetation history and environmental changes in the region between 15.6 and 10.6 ka cal BP, namely during the Late Glacial and the early Holocene, using a multiproxy analysis (pollen-based vegetation and climate reconstruction, sedimentary macrocharcoals, loss-on-ignition, magnetic susceptibility and X-ray fluorescence (XRF) measurements). The results are then compared with other sequences from the Iberian Central System and the whole Iberian Peninsula in order to better understand the past dynamics of the main forest constituents. The pollen record shows a shift from open pine forests ∼15.6–14.7 ka cal BP (Oldest Dryas) to mixed open pine-birch woodlands ∼14.7–14.0 ka cal BP (Bølling). Woodlands were succeeded by a steppe-like landscape until ∼13.4 ka cal BP (Older Dryas), which was replaced again by high-mountain pine forests and riparian woodlands ∼13.4–12.6 ka cal BP (Allerød). A great development of cold steppe grasslands linked to the decline of birch woodlands is documented ∼12.6–11.7 ka cal BP (Younger Dryas). The early Holocene (11.7–10.6 ka cal BP) was characterized by a progressive reforestation of the study area by pine and birch forests in the highlands and oak woods in the lowlands. Temperate tree taxa (Carpinus betulus, Castanea sativa, Corylus avellana, Fraxinus, Juglans, Tilia, and Ulmus) were also common but likely at lower elevations. Pollen of Fagus sylvatica was already recorded during the Late Glacial and the early Holocene. The marked increasing local fire activity during the warmer and wetter Allerød oscillation could be related to a rise in tree cover, supporting the climatically driven character of these fires. Nevertheless, the strong increase in fire activity during the Younger Dryas would probably be related to growing tree and shrub mortality, as well as to the wet/dry biphasic structure of this stadial. The standard “Modern Analogue Technique” has been also applied to the Navamuño sequence to provide quantitative climate estimations for the Late Glacial and the early Holocene periods. This record is one of the few continental archives that show the climatic trend between the Late Glacial and the early Holocene in central Iberia, agreeing with many other regional records from the Western Mediterranean. more...

The origin of modern disjunct plant distributions in the Brazilian Highlands with strong floristic affinities to distant montane rainforests of isolated mountaintops in the northeast and northern Amazonia and the Guyana Shield remains unknown. We tested the hypothesis that these unexplained biogeographical patterns reflect former ecosystem rearrangements sustained by widespread plant migrations possibly due to climatic patterns that are very dissimilar from present-day conditions. To address this issue, we mapped the presence of the montane arboreal taxa Araucaria, Podocarpus, Drimys, Hedyosmum, Ilex, Myrsine, Symplocos, and Weinmannia, and cool-adapted plants in the families Myrtaceae, Ericaceae, and Arecaceae (palms) in 29 palynological records during Heinrich Stadial 1 Event, encompassing a latitudinal range of 30°S to 0°S. In addition, Principal Component Analysis and Species Distribution Modelling were used to represent past and modern habitat suitability for Podocarpus and Araucaria. The data reveals two long-distance patterns of plant migration connecting south/southeast to northeastern Brazil and Amazonia with a third short route extending from one of them. Their paleofloristic compositions suggest a climatic scenario of abundant rainfall and relative lower continental surface temperatures, possibly intensified by the effects of polar air incursions forming cold fronts into the Brazilian Highlands. Although these taxa are sensitive to changes in temperature, the combined pollen and speleothems proxy data indicate that this montane rainforest expansion during Heinrich Stadial 1 Event was triggered mainly by a less seasonal rainfall regime from the subtropics to the equatorial region., This work was funded by FAPESP research grant 2015/50683-2 to P.E. De Oliveira, VULPES Project, Belmount Forum. more...

A high-altitude peat sequence from the heart of the Spanish Central System (Gredos range) was analysed through a multi-proxy approach to determine the sensitivity of high-mountain habitats to climate, fire and land use changes during the last seven hundred years, providing valuable insight into our understanding of the vegetation history and environmental changes in a mountain pass close to a traditional route of transhumance. The pollen data indicate that the vegetation was dominated by shrublands and grasslands with scattered pines in high-mountain areas, while in the valleys cereals, chestnut and olive trees were cultivated. Strong declines of high-mountain pines percentages are recorded at 1540, 1675, 1765, 1835 and 1925 cal AD, which may be related to increasing grazing activities and/or the occurrence of anthropogenic fires. The practice of mountain summer farming and transhumance deeply changed and redesigned the landscape of the high altitudes in central Spain (Gredos range) since the Middle Ages, although its dynamics was influenced in some way by climate variability of the past seven centuries. more...

This work was supported by the Excellence Research Projects Programme from the Andalusian Government, Sevilla, Spain [Project Relictflora-P11-RNM-7033].

Mid-mountain ecosystems provide a broad diversity of resources, heterogeneous relief, and a mild climate, which are all very useful for human necessities. These features enable different strategies such as the terracing of the slopes as well as wide crop diversification. Their relations lead to a parallel co-evolution between the environment and human societies, where fire and grazing become the most effective landscape management tools. This paper presents the results obtained from a multi-proxy study of the Bermú paleoenvironmental record, which is a minerotrophic mire located in the Quintos de Mora National Hunting Reserve (Toledo Mountains, central Spain). The bottom of this core has been dated in the Islamic period (ca. 711–1100 cal AD), and the study shows how the landscape that was built over time in the Toledo Mountains up to the present day is narrowly linked to human development. This study shows the increasing human pressure on the landscape, as well as the subsequent strategies followed by the plant and human communities as they faced diverse environmental changes. Thus, it is possible to attest the main role played by the humans in the Toledo Mountains, not only as a simple user, but also as a builder of their own reflexion in the environment., This research was funded the project REDISCO-HAR2017-88035-P (Plan Nacional I+D+I, Spanish Ministry of Economy and Competitiveness). Reyes Luelmo is funded by a FPU grant (Spanish Ministry of Education, Culture and Sports)., This publication was funded by the Laboratorio di Palinologia e Paleobotanica—CEA 2018 Award for the oral presentation titled ‘A mid-mountain landscape shaped during fourteen centuries in the heart of Toledo Mountains (central Iberia). more...

Cedrus atlantica (Atlas cedar) is a relict and endemic endangered species from northwestern African mountains, whose distribution range has undergone a dramatic reduction over recent decades. Long-term studies are needed for a better understanding of the development of its range as well as for assisting in the implementation of sustainable conservation measures. The multi-proxy analysis of a high-resolution fossil record of 180 cm depth allowed us to depict the final demise of an Atlas cedar population from the western Rif Mountains (Jbel Khesana), despite its high resilience during the last ~4000 years. Currently, Atlas cedar trees are not observed in Jbel Khesana but they still occur in the nearby area as scattered populations on a few mountain tops at altitudes higher than 1400 m a.s.l. Our data show an initial relatively stable period (~4000¿2400 cal. yr BP) followed by a phase where both climatic and human-induced disturbances cause an alternate dominance of oaks and Atlas cedars (2400~1550 cal. yr BP). Then, the increasing aridity and human activities favoured the depletion of Atlas cedar forests (~1550¿800 cal. yr BP). Our record shows that Atlas cedar forests have recovered after each deforestation event, which reveals a high resilience of the species until the mid-20th century, when they became extinct in the study area. The main driver of their local extinction may be attributed to the strong human pressure. Management measures of Atlas cedar in the Rif Mountains should aim at limiting intensive loggings and protecting the existing populations for their local regeneration. more...

Fossil pollen records from 70 sites with reliable chronologies and high-resolution data in the western Mediterranean, were synthesised to document Late Holocene vegetation and climate change. The key elements of vegetation dynamics and landscape construction during Late Antiquity are clear in the light of the fossil pollen records. These are: fire events (natural or anthropogenically induced); grazing activities in high-mountain areas; agriculture; arboriculture; and human settlement in the lowlands. In terms of anthropogenic pressure, the differences recorded between highlands and lowlands suggest an imbalance in land use. Such practices were related to three main types of activities: wood exploitation and management, cultivation, and pastoralism. In lowland areas there seems to be some synchronism in vegetation dynamics during the late antique period, since most of the territories of the western Mediterranean had been deforested by the Early Roman period. However, in mountainous regions, pollen records document a clear asynchrony. more...

Quantifying and reconstructing past vegetation changes is an important step to fully understand human-environment interactions in the past. In this study we present a reconstruction of arboreal cover of six studysites in the Gredos Range (central Spain) over the last 3000 yr based on multivariate statistical analysis (clusteranalysis and non-metric multidimensional scaling, NMDS) of 186 modern pollen samples, modern vegetationdata and six detailed fossil pollen records. The integrated approach allows distinguishing eight modern vegeta-tion communities and linking the fossil pollen records with these vegetation communities as modern analogues.The information of the arboreal cover of the modern pollen sites was used to estimate the past arboreal cover ofthe fossil pollen sites in the Gredos Range. This estimated arboreal cover shows a higher level of landscape open-ness than suggested by the original pollen percentages data. Our results show that the evolution of the arborealcover through time differs along an altitudinal gradient, with a decrease in arboreal cover during the Roman andVisigoth periods (2000–1240 cal BP) at low altitudes and only during the Christian/Feudal period (850–500 calBP) at high altitudes. The applied methodology, integrating fossil pollen data with modern pollen and vegetationdata in one NMDS, allows reconstructing past arboreal cover in a quantitative way., This work was supported by the projects Desirè-HAR2013-43701-P(Plan Nacional I + D + I, Spanish Ministry of Economy and Competi-tiveness) and Relictflora-P11-RNM-7033 (Excellence Research ProjectsProgram from the Andalusian Government), and partly supported bythe Interuniversity Attraction Poles Program IAP 07/09 initiated by theBelgian Science Policy Office. more...

Pollen analyses supported byfifteen AMS14C dates from Fuente de la Leche (1382 m) and Fuente del PinoBlanco (1343 m) peat sequences, in the Gredos range (central Spain), are used to reconstruct the lateHolocene vegetation history in this mountain region. These results are compared with other sequencesfrom the Spanish Central System in order to better understand the past dynamics of the main forestconstituents and to provide a critical view of the dialectic between conifers and deciduous forests. Thevegetation record at Fuente de la Leche starts at 3000 cal yr BP, with the occurrence of rather closedforests composed ofPinus sylvestrisandBetula.Pinus sylvestriswas the dominant pollen taxa for almostthe entire period. However, during the last 850 years,Pinus sylvestrisforests were progressively replacedbyQuercus pyrenaicawoodlands and grasslands, as a result of a high pastoral pressure, until formingmixed woodlands ~400 years ago. The interpretation of Fuente del Pino Blanco record is that dramaticchanges started about 265 years ago. Prior to this date, an open canopy woodland included species (Alnusglutinosa,Quercus pyrenaica) whose distributions no longer exist in the studied area. We suggest that theincrease in agricultural (rye and other cereals) and livestock activities forced a change in the role offire inthe supramediterranean belt of the Gredos range, thus Pyrenean oak canopy was consumed byfires,providing openings forPinus pinasterand broom communities better adapted tofire. more...

BACKGROUND: High-mountain pine forests and broom communities in central Spain today have led to contrasting interpretations of their natural or human-induced origin. AIMS: We evaluated the vulnerability and resilience of high-mountainPinus sylvestris/P. nigra forests and derivedCytisusbroom scrub communities to climate and anthropogenic disturbances. METHODS: We assessed historical transitions from forest to scrub and their relation to climate and human influences, using a multi-proxy paleoenvironmental study (pollen, non-pollen palynomorphs, charcoal, magnetic susceptibility) in three mires in the Gredos Range, western Iberian Central System. RESULTS: High percentages of Pinus sylvestris/nigrapollen and the identification of their macro remains demonstrated that high-mountain pine forests have been present in the oromediterranean bioclimatic belt of the Gredos Range since the mid-Holocene. After that, a major human-induced decline, enhanced by climate conditions, has led to their gradual replacement by broom communities. CONCLUSIONS: Broom communities are derived from ancient pine forests that were intensively transformed by human activities after 700 cal year BP, and largely disappeared byca. 500 cal yr BP. Today’s landscape, dominated by broom scrub and grasslands with scattered stands of pines, shows high resilience and provides suitable refugia for a rich mountain biodiversity which deserves a further protection. more...

This paper describes the patterns and processes of vegetation change and fire history in the Late Holocene (c. 3,140 cal BP) palaeoecological sequence of El Tiemblo, in a mountainous area in central Spain (Gredos range, Spanish Central System), and provides the first Iberian pollen sequence undertaken within a Castanea sativadominated woodland. These new data reassess not only the autochthonous nature of the species in the region and in the Iberian Peninsula, but also the naturalness of well-developed sweet chestnut forests. The study focuses on anthropogenic dynamics linked both to the effects of livestock husbandry and the use of fire for forest clearance. With this aim, non-pollen palynomorphs (coprophilous fungi ascospores) and charcoal accumulation rate are useful indicators for assessing the increasing role of human influence on vegetation, We sincerely thank three anonymous reviewers and the editor for their constructive suggestions and comments. This work was funded by the project HAR2013-43701-P (Spanish Economy and Competitiveness Ministry) “Dinámicas socio-ecológicas, resiliencia y vulnerabilidad en un paisaje de montaña: el Sistema Central (9,000 cal BC-1850 cal AD) (DESIRÈ)”. J.A. López-Sáez is currently supported by a research Grant (Spanish Ministry of Education, Culture and Sport) at Caen Basse-Normandie University. We are grateful to A. López Andreu (RIP) and P. Sáez Navas for their collaboration and assistance during the field work. more...

[EN] We present the palynological study of Pozo de la Nieve peat bog, located in a very valuable socio-cultural placement within the Iruelas Valley Natural Park (Gredos range, Iberian Central System). We have focused in relating landscape changes to natural resources management and climatic events. Firstly, we carried out seven radiocarbon dates suggesting the origin of this record ca. 240 cal BC. The palynological data show the existence of dense high-mountain pine woodlands dominated by Pinus sylvestris/nigra from the Late Iron Age to the Muslim period. Later, from the Christian period, anthropogenic activities have intensified, especially livestock grazing in the Contemporary Age. Its consequences are the progressive disappearance of highmountain pine forests and the extension of grasslands by means of fire, which has shaped current landscape dominated by broom communities, [ES] En este trabajo se presenta el análisis palinológico de la turbera de Pozo de la Nieve, localizada en el Parque Natural del Valle de Iruelas (Ávila), un área de alto valor sociocultural dentro de la Sierra de Gredos (Sistema Central). Con el objetivo de relacionar los cambios en el paisaje con la explotación de los recursos naturales y eventos climáticos, en primer lugar se han realizado 7 dataciones radiocarbónicas que sitúan el inicio del registro sedimentario ca. 240 cal BC. Los datos polínicos indican la existencia de un denso pinar altimontano dominado por Pinus sylvestris/nigra desde la Segunda Edad de Hierro hasta el periodo islámico. A partir del periodo cristiano las actividades antrópicas se intensifican, especialmente la ganadería en la Edad Contemporánea, lo cual conlleva la progresiva desaparición del pinar de alta montaña y el desarrollo de pastizales mediante el manejo del fuego, situación que culmina con el desarrollo del paisaje actual dominado porpiornales pirófilos. more...

[EN] Salt exploitation in the Villafáfila lagoon complex (Tierra de Campos, Zamora) is one of the most important events since Prehistory in the northern plateau of the Iberian Peninsula. Salt production is documented from the Bell Beaker (ca. 2450 cal BC). In 2013, a core drilling was performed in the salty swamp of the Laguna de las Salinas. The analysis of pollen and non-pollen palynomorphs of this record suggests the origin of the lagoon eight thousand years ago linked to the 8,2 ky cal BP climatic event, a very anthropized environment from the beginning of the Chalcolithic period ca. 3300 cal BC and the subsequent exploitation of salt, the gradual and definitive degradation of the holm oak forest from the Bronze Age onwards, and, in general, a wide climatic variability, with alternate humid and arid phases throughout the palaeoenvironmental sequence, [ES] La explotación de la sal en el complejo lagunar de Villafáfila (Tierra de Campos, Zamora) es uno de los eventos más importantes de la meseta norte de la península ibérica desde la Prehistoria. La producción de sal se documenta a partir del periodo Campaniforme (ca. 2450 cal BC). En 2013, se efectuó un sondeo mecánico en los pastizales húmedos anexos a la Laguna de las Salinas. El análisis de polen y microfósiles no polínicos de este registro sugiere el origen de la laguna hace al menos ocho mil años vinculado al evento climático 8,2 ka cal BP, un ambiente muy antropizado desde los inicios del Calcolítico ca. 3300 cal BC y la posterior explotación de la sal, la degradación paulatina y definitiva del bosque de encinas a partir de la Edad del Bronce, y, en general, una amplia variabilidad climática alternando fases húmedas y áridas a lo largo de toda la secuencia paleoambiental., Los autores agradecen al organismo gestor de la Reserva Natural Lagunas de Villafáfila, dependiente de la Fundación Patrimonio Natural de la Junta de Castilla y León, las facilidades ofrecidas para el desarrollo de este trabajo. Éste ha sido financiado por una ayuda de investigación concedida al primer autor por la Consejería de Cultura y Turismo de la Junta de Castilla y León en 2013 para el Estudio arqueobotánico y paleoambiental del entorno de las lagunas de Villafáfila; y parcialmente por el Proyecto HAR2013-43701-P del Plan Nacional I+D+I del Ministerio de Economía y Competitividad more...

International audience; This study reconstructs and interprets the changing range of Atlas cedar in northern Morocco over the last 9,000 years. A synthesis of fossil pollen records indicated that Atlas cedars occupied a wider range at lower elevations during the mid-Holocene than today. The mid-Holocene geographical expansion reflected low winter temperatures and higher water availability over the whole range of the Rif Mountains relative to modern conditions. A trend of increasing aridity observed after 6,000 years BP progressively reduced the range of Atlas cedar and prompted its migration toward elevations above 1,400 masl. To assess the impact of climate change on cedar populations over the last decades, we performed a transient model simulation for the period between 1960 and 2010. Our simulation showed that the range of Atlas cedar decreased by about 75% over the last 50 years and that the eastern populations of the range in the Rif Mountains were even more threatened by the overall lack of water availability than the western ones. Today, Atlas cedar populations in the Rif Mountains are persisting in restricted and isolated areas (Jbel Kelti, Talassemtane, Jbel Tiziren, Oursane, Tidighine) that we consider to be modern microrefugia. Conservation of these isolated populations is essential for the future survival of the species, preserving polymorphisms and the potential for population recovery under different climatic conditions. more...

[EN] The evidence for Neolithic settlement sites in the province of Ávila (Spain) is still very scanty and consists mainly of certain archaeological items (pottery with fluted or impressed decorations of the Early Neolithic ceramic tradition, flint microliths and a few polished stone tools), which have been found during the excavation of sites of a later date. These excavations have therefore produced inconclusive dating evidence for those findings. Archaeological investigations at La Atalaya, in Muñopepe, revealed a long and complex history of occupation going from the Early Neolithic to the Copper Age, located around granite outcrops some of which are decorated with prehistoric rock paintings. In this paper, we present the cultural sequence of La Atalaya, based on stratigraphic information, chronological data and a technotypological analysis of the pottery and lithic collections. Environmental and economic information is also provided. Finally, some hypotheses about the Neolithization process in the south-western area of the Spanish Northern Meseta are suggested, [ES] El Neolítico es un momento no muy bien caracterizado en la provincia de Ávila. A día de hoy son todavía pocos los asentamientos documentados, los cuales se muestran a través de cerámicas acanaladas o impresas con motivos propios del Neolítico Interior, microlitos en sílex o algún pulimentado. Estos materiales carecen de contexto, al haberse hallado bien en el transcurso de prospecciones superficiales o durante la excavación de niveles prehistóricos más modernos, lo que ha motivado que no se cuente con información precisa sobre el marco cronológico en el que ubicar esas piezas. Los trabajos arqueológicos llevados a cabo en el yacimiento de La Atalaya, en Muñopepe, han revelado una compleja y dilatada secuencia de ocupación desde el Neolítico Antiguo a la Edad del Cobre, la cual se desarrolló en torno a bolos graníticos decorados con pinturas rupestres. Estudiamos aquí la trayectoria cultural de La Atalaya, conjugando la información estratigráfica, los resultados de las dataciones absolutas y el análisis tecno-tipológico de las colecciones cerámicas y líticas, sin olvidarnos de cuestiones paleoambientales y paleoeconómicas. Todo ello nos brinda la oportunidad de debatir los mecanismos del proceso de neolitización en el sector sudoccidental de la Submeseta Norte española, Este trabajo ha sido financiado por la Secretaría de Estado de Investigación, Desarrollo e Innovación a través de un proyecto de I+D del Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia, Subprograma Estatal de Generación de Conocimiento del Ministerio de Economía y Competitividad titulado “El Neolítico en los roquedos de las serranías abulense y salmantina” (HAR2014-59883-P), el cual profundiza en una línea de investigación abierta por un proyecto anterior “El Neolítico en los roquedales graníticos abulenses” (HAR2009-11025). Asimismo, parte de los estudios aquí presentados se han visto sufragados por la Junta de Castilla y León y por el proyecto de la Dra. Leonor Peña Chocarro “Origins and spread of agriculture in the south-western Mediterranean region” (AGRIWESTMED), financiado por el European Research Council. Los trabajos de excavación arqueológica y selección de materiales corrieron a cargo de los arqueólogos de la empresa AICARA, Arqueología y Patrimonio Cultural, a quienes agradecemos las facilidades prestadas para llevar a cabo este estudio, y muy especialmente a Jesús Álvaro Arranz Mínguez y Alicia Gómez Pérez more...

In this study, we investigated the relationship between vegetation and modern-pollen rain along the elevational gradient of Mount Paggeo. We apply multivariate data analysis to assess the relationship between vegetation and modern-pollen rain and quantify the representativeness of forest zones. This study represents the first statistical analysis of pollen-vegetation relationship along an elevational gradient in Greece. Hence, this paper improves confidence in interpretation of palynological records from north-eastern Greece and may refine past climate reconstructions for a more accurate comparison of data and modelling. Numerical classification and ordination were performed on pollen data to assess differences among plant communities that beech (Fagus sylvatica) dominates or co-dominates. The results show a strong relationship between altitude, arboreal cover, human impact and variations in pollen and nonpollen palynomorph taxa percentages. more...

Human impact is a key factor in the evolution of landscape since the mid-Holocene. In this work landscape changes in a mountainous area in central Spain are examined through the analysis of pollen at Pena Negra mire (Caceres), since its formation during the transition period between the third and second millennium cal. b.c. The study focuses on anthropogenic dynamics linked to the effects of livestock husbandry and the use of fire for forest clearance, as the mire is located close to a natural pass across the Bejar Range. With this aim, non-pollen palynomorphs and charcoal accumulation rate are useful indicators to assess the increasing role of human influence on vegetation. Grazing activities are continuously detected from the base of the profile, with maxima in the last millennium, while the use of fire is more pronounced from 3000 to 1000 cal. b.p. The discontinuous presence through the profile of forest species like chestnut, walnut, beech, elm or yew has also been analyzed. more...

The study of environmental change during the ‘Little Ice Age’ (‘LIA’) offers a great potential to improve our current understanding of the climate system and human–environment interactions. Here, a high-resolution multiproxy investigation of a Mediterranean mire from central-western Spain, covering the last ~700 years, was used to reconstruct peat dynamics and land-use change and to gain further insights into their relationship with ‘LIA’ climate (temperature and moisture). To accomplish this, concentrations and accumulation rates of major and minor lithogenic (Si, K, Ti, Rb and Zr) and biophilic (C and N) elements, as well as humification indices (UV-absorbance and Fourier-transform infrared spectroscopy (FTIR)) and pollen and non-pollen palynomorphs, were determined. Peatland dynamics seems to have been coupled to changes in solar irradiance and hydrological conditions. Our results point to wetter conditions after the mid-16th century, although with high intra-annual fluctuations. At the late 18th century, when solar activity was systematically higher than before, peat carbon accumulation rates (PCAR) showed a continuous increase and the humification indices suggest a change towards more humified peat. Enhanced soil erosion occurred at ~AD 1660–1800 (SE1), ~AD 1830–1920 (SE2) and ~AD 1940–1970 (SE3), although a minor increase in Si fluxes was also detected by ~AD 1460–1580. All phases coincided with higher abundances of fire indicators, but the changes recorded during the ~AD 1460–1580 event and SE1 coincide with the Spörer and Maunder minima, so a climatic influence on soil erosion cannot be discounted. Changes in the sources of mineral matter to the catchment between ~AD 1550 and ~AD 1650 and since the mid-17th century were likely related to modifications of tree cover and/or variations in wind strength., This work was funded by the projects HAR2013-43701-P (Spanish Economy and Competitiveness Ministry) and CGL2010-20672 (Spanish Ministry of Science and Innovation). This research was also partially developed with Xunta de Galicia funding (grants R2014/001 and GPC2014/009). N. Silva-Sánchez is currently supported by a FPU pre-doctoral grant (AP2010-3264) funded by the Spanish Government more...

The raised bog Culazon (43° 13′ 58″ N, 4° 29′ 21″ W; 592 m above sea level (a.s.l.); size c. 1 ha) lies on the northern slope of the Cantabrian Mountains in the Lamason valley. The study area has b... more...

A total of 75 surface samples collected from mosses in the Quercus pyrenaica forests of the Spanish Central System mountains were analysed for their pollen content. The samples were taken from six different Quercus pyrenaica phytosociological associations between 443 and 1657 m a.s.l. and fall within distinct rainfall and temperature regimes. The aims of this paper are to provide new data on the modern pollen rain from Central Spain, and to perform these data using multivariate statistics (hierarchical cluster analysis and principal component analysis) and pollen percentages. We could distinguish first between unaltered and disturbed forest landscapes and among different Quercus pyrenaica forest associations based on climatic gradients (rainfall pattern, summer moisture). This analysis allowed us to identify a set of pollen taxa markers which could assist in distinguishing these oak forest communities. more...

Aim of study. The diachronic study of vegetation change through palynological analysis of sedimentary deposits is an essential tool both to design sound strategies on landscape management and to understand its anthropogenic dynamics., Area of study. La Meseguera mire (Ladrillar, Cáceres, Spain) is located in the Hurdes region in the western part of Iberian Central System and started to develop at the beginning of the Islamic period (ca. 770 cal AD), in an area widely dominated by heathland., Material and methods. Pollen, non-pollen palynomorphs and charcoal accumulation rate (CHAR) combined with historical data are useful indicators to assess the increasing role of human influence on vegetation., Main results. The use of fire and livestock husbandry represents the main drivers of landscape change in the course of the history. The establishment of forest afforestation plans, from the middle of 20th century, changed substantially the regional features. The sporadic presence of beech pollen is detected until 16th century, which implies the most western location in the Iberian Central Mountain System., Research highlights. The integration of pollen analysis and historical data is an essential tool when studying the changes in Holocene vegetation. These changes have been mainly driven by anthropogenic disturbances, more specifically by fire and livestock husbandry. more...

We present a multiproxy characterization of a complex, polycyclic soil sequence from Les Alcusses, Moixent(Valencia, SE Spain). The area has abundant settlements dating from early Neolithic to Roman times. The sequence comprises six main units, dating back to 8.7-8.5kacalBP. We integrated mineralogy, inorganic (pH, grain size, elemental composition) and organic chemistry (pyrolysis gas chromatography/mass spectrometry, pyrolysis-GC/MS), micro-charcoal, pollen and non-pollen palynomorph (NPP) data. All data is contextualized within a framework of archaeological information and radiocarbon dating, with the aim of deciphering the Holocene environmental changes.We infer a shift from wetter and warmer, in the early-mid Holocene, to drier and cooler climatic conditions with increased fire occurrence, in the mid-late Holocene (particularly after 5.3kacalBP). Although the pollen record indicates a rapid forest retreat and expansion of grasslands for the Neolithic period, local proxies (molecular soil OM indicators and NPP) point to the presence of pine forest in the studied location well after the regional decline started. The same proxies suggest a sharp forest decline after about 7.0kacalBP. Strong soil erosion, likely linked both to climatic instability and the intensification of human exploitation, resulted in a hiatus from the late Neolithic to the Roman period. A certain climate amelioration, wetter conditions and land abandonment or, at least, lower human pressure, are suggested for the late Roman period/Early Middle Ages. Direct evidence of changes in soil properties due to agriculture was not detected in the sequence except for the upper soil unit studied, which reflects intense agricultural management (with the possible use of agrochemicals). © 2014 Elsevier Ltd., This study was funded by the European Research Council (Advanced Grant No. 2305619, project ‘AGRIWESTMED: Origins and spread of agriculture in the western Mediterranean region’) and the Diputación de Valencia-Museo de Prehistoria de Valencia (2009/CI585). Daniel Abel Schaad and Judith Schellekens were supported by AGRIWESTMED project. more...

In this paper we present a review of the available Holocene pollen records from the Spanish Central System (113 sites and 150 14C dates). Palynological data obtained from pollen analyses of peat-bogs, lakes and archaeological sites, as well as radiocarbon dating, were used to infer the human impact on vegetation and landscape during the last 9 millennia. The Neolithic contribution to the configuration of landscape is scarce, limited to the valleys, while Chalcolithic settlements and their related activities (agriculture and grazing) represent the first evidence of significant human impact on the high-mountains. The pollen record has allowed us to relate two cultural periods of changing, the Copper Age–Early Bronze Age and Late Bronze Age–Early Iron Age transitions, to abrupt climate disruptions, the so-called 4.2 and 2.8 ka cal BP events respectively. From the Iron Age to the Early Middle Ages, anthropic activities were still sporadic, mainly located in the lowlands, but from the Feudal Period onwards, when La Mesta transhumance system takes place, high-mountain landscapes changed dramatically. Late Modern Period brings a further intensification of human pressure, especially related to forestry, with widespread pinewood afforestation., We are indebted to the CONSOLIDER-INGENIO 2010 Program (CSD2007-00058), EXCELENCIA 2011 Program (RNM-7033) and AGRIWESTMED (ERC-Advanced Grants, proposal n° 230561) more...

Persistence of relict tree species in Mediterranean environments is becoming increasingly unlikely in view of ongoing and future global change. The variability in the Holocene climate and more recent anthropogenic impacts have driven many populations to fragmentation and isolation, and even to extinction. However, some have persisted to the present day. The understanding of their evolution requires long-term studies, in which pollen analysis is a key approach both for formulating hypotheses and supporting results from other disciplines. Mountain ranges have played and still play an essential role as both glacial and interglacial refugia during the Quaternary. The Spanish Central System harbors an exceptional diversity due to its geographical location and complex topography. Some cold-adapted species have survived here with significant proportions of their southernmost populations, often displaying striking adaptations to their changing environments. This work contains a comprehensive review of the palynological investigations conducted in the Spanish Central System, and reveals the distribution of genera such as Taxus, Betula, Fagus, Carpinus and Tilia throughout the Holocene. We also highlight the scarcity of well-dated and high-resolution works, which may contribute to a better understanding of their recent and future evolution. more...

La construcción de los paisajes vegetales en la montaña media cantábrica es una historia larga y compleja que puede ser interpretada como una herencia de la distinta intensidad con la que han actuado a lo largo del tiempo las dinámicas naturales (climáticas y/o geomorfológicas) y las inducidas por la acción del hombre (uso ganadero, agrícola, y especialmente forestal derivado de las demandas de la Marina, de las ferrerías, o de las comunidades campesinas). Las fluctuaciones en la intensidad de los factores puede interpretarse a través del análisis conjunto de los hechos geomorfológicos, de las comunidades vegetales y de estudios palinológicos a alta resolución., Este trabajo se ha realizado dentro del Plan Nacional de I+D+i 2008-2011 con el Proyecto CSO2009-14116-C03-02 (subprograma GEOG) y del Programa Consolider de Investigación en Tecnologías para la valoración y conservación del Patrimonio Cultural -TCP-CSD2007-00058 more...

[EN] Palaeobotanical studies are a very interesting tool for evaluating past vegetation, climatic variability and human pressure on the landscape. In this paper we offer an overview of Holocene evolution of the yew (Taxus baccata L.) in the Basque Mountains (Northern Iberian Peninsula). For this purpose, we have collected all macro- and micro-remain evidence of the presence of yew within its chronological framework. The results suggest the existence of a period of expansion of yew populations during the Middle Holocene and a regression phase in the Late Holocene., [ES] Los estudios paleobotánicos son una herramienta de gran interés para conocer la evolución de la cubierta vegetal del pasado, además de las condiciones climáticas y la dinámica antrópica. Pero también resulta muy útil a la hora de evaluar la historia de particular de algunas especies. En este trabajo ofrecemos una visión sintética de la evolución holocena del tejo (Taxus baccata L.) en las montañas vascas (Norte de la Península Ibérica). Para ello hemos recogido todos los depósitos con macrorestos o microrrestos botánicos de tejo, así como su adscripción cronológica. Los resultados sugieren la existencia de un período de expansión de los tejos durante el Holoceno medio, así como una fase de regresión durante el Holoceno final. more...

[EN] Fifty-eight modern pollen surface samples from different Scots pine forest communities (Pinus sylvestris var. iberica Svoboda) in the Iberian Central System (central Spain) were palynologically and statistically analyzed (using hierarchical cluster analysis and principal component analysis) to derive correlations between pollen assemblages and environmental gradients at the sampled points. Numerical classification and ordination were performed on pollen data to assess similarities among (central Iberian)-Scots pine forest phytosociological associations. The results show a strong relationship between altitude, temperature, rainfall, arboreal cover and variations in pollen taxa percentages. The statistic discrimination of some of these forest communities has allowed us to propose three new associations., [ES] Cincuenta y ocho muestras de lluvia polínica actual, procedentes de distintas comunidades forestales de pino albar (Pinus sylvestris var. iberica Svoboda) en el Sistema Central ibérico (centro de España), fueron analizadas palinológica y estadísticamente (mediante análisis de cluster jerárquico y análisis de componentes principales) para establecer correlaciones entre los espectros polínicos y gradientes medioambientales. La clasificación numérica y la ordenación fueron realizadas sobre los datos polínicos para delimitar posibles similitudes entre las distintas asociaciones fitosociológicas de los bosques de pino albar centro-ibérico. Los resultados muestran que existe una fuerte correlación entre la altitud, temperatura, precipitación y cobertura arbórea respecto a las variaciones en los porcentajes de los principales morfotipos polínicos. La discriminación estadística de algunas de estas formaciones forestales nos hace proponer tres nuevas asociaciones. more...

15 páginas, 4 figuras, 1 tabla., This article describes the patterns and processes of vegetation change and fire history in the Late Holocene (c. 2400 calendar year BP) palaeoecological sequence of Lanzahíta, Sierra de Gredos in central Spain, and provides the first Iberian pollen sequence undertaken within a monospecific Pinus pinaster woodland. These new data reassess not only the autochthonous nature of this pine species in the region and the Iberian Peninsula, but also the naturalness of well-developed cluster pine forests. Conflicts of palaeoecological evidence with phytosociological models of vegetation dynamics in the study region, and the relationships of P. pinaster with fire occurrence in Mediterranean-type ecosystems, are discussed., This study was funded by the projects HAR2008-06477-C03-03/HIST, CGL-2006-2956-BOS (Plan Nacional I + D + i, Ministry of Education and Science, Spain), CSD2007-00058 (Consolider Program, Consejo Superior de Investigaciones Científicas, Spain) and Paleodiversitas Network (Fundación Séneca, Murcia). more...