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Los pinsapares de Abies pinsapo son una de las formaciones boscosas más originales de la península ibérica. A pesar de la singularidad de estos ecosistemas, hasta el momento ningún análisis de microfósiles polínicos había sido emprendido en aquellos territorios donde esta especie, en peligro de extinción, aún pervive. Con este trabajo se presentan los primeros resultados en los que, haciendo uso del registro fósil, han podido ser identificados los impactos climáticos pasados y los cambios de uso de suelo histórico en la evolución de las poblaciones del sur de la península ibérica para el Holoceno final (1180 AD hasta el presente). Los resultados son comparados con las fluctuaciones climáticas y cambios en el manejo forestal documentados en los últimos ocho siglos. La secuencia de polen muestra una fase de estabilidad estructural y estado de conservación óptimo del pinsapar durante el Período Musulmán (~1180-1400 AD), etapa que se desarrolla en la Anomalía Climática Medieval (ACM). A continuación, se inicia un proceso de degradación de estos bosques en el Período Cristiano concurrente con la Pequeña Edad de Hielo, PEH (ca. 1400-1530 AD). El Período Moderno (1530-1800 AD; PEH) está vinculado a la gestión forestal intensiva, relacionada con la industria naval. Posteriormente, se registra una reducción y declive progresivo de estas formaciones que tiene como punto de partida la Edad Contemporánea (Período Industrial; PI) y que culmina con un paisaje profusamente deforestado en el Calentamiento Reciente (CR).

A set of 30 modern pollen samples collected in pine communities of the Gúdar Range (southeastern Iberian System) has been investigated to determine the relationships between pollen percentages and vegetation composition along a ~ 1000 m elevation transect. Pollen representation was estimated by comparing the presence of plant taxa from a recent vegetation survey with pollen spectra. Classification and ordination of modern pollen samples indicated the existence of eight vegetation units, which can be assigned to the six studied pine forest communities. Lowland forests are clearly discriminated from high-altitude ones. These analyses also allow separating Pinus nigra and P. pinaster communities according to their tree cover, and even those of P. sylvestris according to the bioclimatic belt they inhabit. We show that it is possible to obtain distinct pollen markers for Mediterranean pine forest communities. These results will also improve the reconstruction of pine forests from fossil pollen diagrams, as far as modern pollen rain studies are carried out in specific regions, an approach which can be extrapolated to other plant formations regardless the involved territory.

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

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.

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., Ministerio de Ciencia e Innovación (MICINN), Ministerio de Economía y Competitividad (MINECO)/Gobierno de Andalucia/Fondo Regional de Desarrollo Económico(FEDER), Plan Andaluz de Investigación, Desarrollo e Innovación (PAIDI 2020)//Fondo Europeo de Desarrollo Regional(FEDER), Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

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.

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.

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.

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.

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.

The use offire and, consequently, its severity and incidence on the environment have grown steadily during the last millennia throughout theMediterranean. This issue can be assessed in several mountain ranges of central Iberia where changes in the management policy on anthropicactivities and exploitation of high-mountain environments have promoted a remarkable increase onfire frequency. Our research focuses onfire dynamics throughout the last 3,000 years from three peat bog charcoal records of the Gredos range (central Iberia). Our aim is toreconstruct pastfire regimes according to forest vegetation typology (Castanea sativa,Pinus pinaster, andPinus sylvestris). Charcoal influxshows low values between 3,140 and 1,800 cal. yearBPwhen forests were relatively dense in both high and mid-mountain areas. Fireappeared synchronous between 1,800 and 1,700 cal. yearBPfor Lanzahíta and Serranillos and around 1,400–1,240 cal. yearBPfor the threesites, suggesting anthropogenicfire control between the Late Roman and Visigothic periods that can be related to the cultivation of olive treesin the valleys and a greater human impact in high-mountain areas. By contrast, during the Muslim period (1,240–850 cal. yearBP),firedynamics becomes asynchronous. Later,fires turn again coeval in the Gredos range during the Christian period (850–500 cal. yearBP)and can be also correlated with drought phases during the Late Medieval Warm Episode. In short, our study demonstrates thatfire activityhas been enormously variable during the late Holocene in response to both short-term and long-term regional and global climate, vegetationdynamics, and land use changes.

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.

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.

[EN] 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., [ES] Las especies mediterráneas incluidas en el género Abies, y Cedrus atlantica presentan en la actualidad unas áreas de distribución muy limitadas. En este trabajo, se describen el origen y las rutas migratorias seguidas por Abies pinsapo, A. marocana, A. tazaotana y Cedrus atlantica, desde los inicios del Terciario hasta la actualidad, así como las posibles causas que han llevado a sus poblaciones a su estado actual de aislamiento y peligro de extinción. Abies y Cedrus habrían alcanzado el Mediterráneo Occidental junto con otros elementos de la flora arctoterciaria entre el Eoceno Medio (45 Ma) y el Oligoceno (30 Ma). Posteriormente, experimentaron procesos de especiación hasta fechas relativamente recientes, en los que la apertura del estrecho de Gibraltar (5.33 Ma) habría jugado un papel esencial. A lo largo de las glaciaciones-deglaciaciones del Cuaternario, abetos y cedros mediterráneos habrían permanecido en refugios montañosos del sur de la península ibérica y del norte de África. A pesar de presentar cierta expansión y migración altitudinal coincidiendo con el óptimo térmico del Holoceno Medio, estas especies han sufrido un notable declive posterior de sus poblaciones, como consecuencia del incremento de la aridez y del impacto de las actividades humanas. El desarrollo de las estrategias de conservación más adecuadas requiere una mejor información sobre la respuesta de estas especies a las distintas perturbaciones, para lo cual resulta indispensable conocer su evolución a lo largo del tiempo. El registro fósil, tanto de macrorrestos como de polen, junto a diversos estudios genéticos contribuyen a evaluar su resiliencia y vulnerabilidad

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 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

[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.

[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

El género Cedrus tiene una larga historia en Europa. A lo largo del Pleistoceno ha experimentado una fuerte reducción, que le ha llevado a desaparecer de las penínsulas mediterráneas. En la actualidad el cedro (Cedrus atlántica (Endl.) Manetti ex Carrière) es una especie endémica del Noroeste de África, que ha sufrido un severo declive durante el Holoceno Reciente. Para estudiar su evolución a lo largo de los últimos 4000 años, se presenta un trabajo de alta resolución, en el que hemos analizado el polen, microfósiles no polínicos y la tasa de acumulación de carbones (CHAR), en una turbera localizada en el Jbel Khesana, en el sector occidental de las montañas del Rif. También se ha llevado a cabo un estudio geoquímico. El trabajo confirma el declive continuo de los bosques de cedro, especialmente durante los últimos mil años, hasta su extinción en la sierra del macizo rifeño. La migración de los cedrales a zonas altas, inducida por el clima, así como el impacto antropogénico, concretamente las cortas selectivas y el uso extensivo del fuego, se discuten como principales factores de su extinción.

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.

A multi-proxy palaeoenvironmental study (pollen, non-pollen palynomorphs, charcoal particles) of a mire, located in the western Spanish Central System (Gredos range), was undertaken to trace historic human activities related to woodland clearance and past land-uses at high altitudes during the last three millennia. The results of this study constrained by 4 AMS radiocarbon measurements are combined with archaeological data and compared with similar research carried out at the same altitude in mountains of central Iberia. The pollen data indicate that high-mountain areas were dominated by birch and pine woodlands until c. 2350 years. From this date on a strong forest decline is recorded during the Late Iron Age and a deeper one c. 1500 years ago in the Visigothic period, which may be related to increasing grazing activities and/or the occurrence of anthropogenic fires. Cereals and faba beans were cultivated in the surrounding valley since c. 2900 cal BP, while chestnut, walnut and olive tree are documented mainly from the Roman period onwards.