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Mediterranean mountainous environments are biodiversity hotspots and priority areas in conservation agendas. Although they are fragile and threatened by forecasted global change scenarios, their sensitivity to long-term environmental variability is still understudied. The Sierra Nevada range, located in southern Spain on the north-western European flanks of the Mediterranean basin, is a biodiversity hotspot. Consequently, Sierra Nevada provides an excellent model system to apply a palaeoecological approach to detect vegetation changes, explore the drivers triggering those changes, and how vegetation changes link to the present landscape in such a paradigmatic mountain system. A multi-proxy strategy (magnetic susceptibility, grain size, loss-on-ignition, macroremains, charcoal and palynological analyses) is applied to an 8400-year long lacustrine environmental archive from the Laguna de la Mosca (2889 masl). The long-term ecological data show how the Early Holocene pine forests transitioned towards mixed Pinus-Quercus submediterranean forests as a response to a decrease in seasonality at ~7.3 cal. kyr BP. The mixed Pinus-Quercus submediterranean forests collapsed drastically giving way to open evergreen Quercus formations at ~4.2 cal. kyr BP after a well-known aridity crisis. Under the forecasted northward expansion of the Mediterranean area due to global change-related aridity increase, mountain forests inhabiting territories adjacent to the Mediterranean Region could experience analogous responses to those detected in the Sierra Nevada forests to the Mid to Late Holocene aridification, moving from temperate to submediterranean and then Mediterranean formations.

Understanding long-term fire ecology is essential for current day interpretation of ecosystem fire responses. However palaeoecology of fire is still poorly understood, especially at high-altitude mountain environments, despite the fact that these are fire-sensitive ecosystems and their resilience might be affected by changing fire regimes. We reconstruct wildfire occurrence since the Lateglacial (14.7. cal. ka BP) to the Mid-Holocene (6. cal. ka BP) and investigate the climate-fuel-fire relationships in a sedimentary sequence located at the treeline in the Central Spanish Pyrenees. Pollen, macro- and micro-charcoal were analysed for the identification of fire events (FE) in order to detect vegetation post-fire response and to define biomass-fire interactions. mean fire intervals (mfi) reduced since the Lateglacial, peaking at 9-7.7. cal. ka BP while from 7.7 to 6. cal. ka BP no fire is recorded. We hypothesise that Early Holocene maximum summer insolation, as climate forcing, and mesophyte forest expansion, as a fuel-creating factor, were responsible for accelerating fire occurrence in the Central Pyrenees treeline. We also found that fire had long-lasting negative effects on most of the treeline plant communities and that forest contraction from 7.7. cal. ka BP is likely linked to the ecosystem's threshold response to high fire frequencies. © 2014 Elsevier B.V., This research has been funded by the projects DINAMO (CGL2009-07992) (funding EGPF — grant ref. BES-2010-038593 and MSC), DINAMO2 (CGL2012-33063), ARAFIRE (2012 GA LC 064), GRACCIE-CONSOLIDER (CSD2007-00067). GGR was funded by the Juan de la Cierva Program (grant ref. JCI2009-04345) and JAE-Doc CSIC Program, LLM was supported by a postdoctoral MINT fellowship funded by the Institute for the Environment (Brunel University), AMC is a Ramón y Cajal fellow (ref: RYC-2008-02431), APS holds a grant funded by the Aragon Government (ref. 17030G/5423/480072/14003) and JAE holds a grant funded by the Basque Country Government (BFI-2010-5). We are indebted to Beatriz Bueno and Aida Adsuar for sampling processing and laboratory analyses and to César Morales del Molino for productive discussions on the ideas of this paper. We are grateful to Steven M. Holland for providing the free software to calculate rarefaction (Analytic Rarefaction), which is available at http://strata.uga.edu/software/.

11 páginas, 5 figuras, 3 tablas., A multi-proxy study (pollen and NPPs, geochemical composition and radiocarbon dating), combined with principal components analysis, was applied to a core sampled in the Monte Areo mire (Asturias, N Spain), which covers the last 11,600 years cal BP. Both signals of Holocene climate change and transformations by human activities were recorded. The cooler stage of the early Holocene, the Hypsithermal and the Neoglaciation periods, were indentified but later Holocene abrupt climate changes seem not to have been recorded due to the particular evolution of the fen/mire system and the impact of human activities on the local hydrology. Evidence for human activity included a first phase of pastoralism by 7300 cal BP, and an extraordinary record of adoption and establishment of agriculture. The first evidence of cereal pollen, dated to approximately 6700 cal BP, represents one of the earliest records of agriculture in northern Spain. Contrary to previous studies which, based on assumed biogeographical limitations, proposed a late adoption of agriculture in the area, our results indicate a rapid expansion of agriculture in northern Spain from the eastern to the westernmost areas more in agreement with recent archaeobotanical investigations ([Zapata et al., 2004] and [Zapata et al., 2005]). The research also indicates that climate and human activities interplayed to determine the evolution of the studied area, and that a multi-proxy approach applied to natural archives appropriately located (in areas with evidence of past human occupation) is a productive way to obtain circumstantial evidence of early human activity., This work was funded by the projects HAR2008-06477-C03-03/ HIST (Plan Nacional I+D+i, Ministry of Science and Innovation, Spain), CDS-TCP (CSD2007-00058, Programa Consolider-Ingenio 2010) and AGRIWESTMED (ERC-Advanced Grants, proposal no 230561).

18 páginas, 13 figuras., Recent, high-resolution palaeoecological records are changing the traditional picture of post-glacial vegetation succession in the Iberian Peninsula. In addition to the influence of Lateglacial and Early Holocene climatic changes, other factors are critical in the course of vegetation development and we observe strong regional differences. The floristic composition, location and structure of glacial tree populations and communities may have been primary causes of vegetation development. Refugial populations in the Baetic cordilleras would have been a source, but not the only one, for the early Lateglacial oak expansions. From Mid to Late Holocene, inertial, resilient, and rapid responses of vegetation to climatic change are described, and regional differences in the response are stressed. The role of fire, pastoralism, agriculture, and other anthropogenic disturbances (such as mining), during the Copper, Bronze, Iberian, and Roman times, is analysed. The implications of ecological transitions in cultural changes, especially when they occur as societal collapses, are discussed., This research has been funded by the national projects CGL-2009- 6988, CGL-2006-2956-BOS and HAR2008-06477-C03-03/HIST, LIMNOCAL (CGL2006-13327-C04-01), GRACCIE (CSD2007-00067) and Hum2004-04939 MCYT (Ministerio de Educación y Ciencia, Madrid), PEPLAN (Dirección General del Medio Natural Región de Murcia), and Paleodiversitas Network (Fundación Séneca, Murcia).

Correlations between ecological and cultural changes occurred during a short period between the end of Subboreal and the beginning of Subatlantic in the Amblés Valley (Ávila, central Spain) are analyzed, taking into account palaeopalynological and archaeological data. Plant dynamics from pollen analyses, both from archaeological sites and peat bogs, have been interpreted in relation to human settlements and the transformation of economic practices. These provided a comprehensive hypothesis on human/climate interactions at the beginning of the 1st millennium cal BC. There was an ecological crisis in the region that lasted for a century (ca. 850-760 cal BC). This was especially sharp due to both the geographical constraints of the area and its previous agrarian history. This event implied a sudden and abrupt climatic change from xeric and warm conditions (Subboreal) to more humid and cooler ones (Subatlantic). Environmental stress derived from climatic crisis could be an important factor in the explanation of the historical process, whose main consequences were both the origin of the Iron Age peasant villages and the end of the 'dehesa' type landscape. © 2008 Elsevier Ltd and INQUA.

10 páginas, 5 figuras, 1 tabla., A high-resolution sedimentary sequence sampled from the Portlligat Bay (NEIberianPeninsula) has been studied in order to assess its palaeoecologicalpotential. This sedimentary sequence is considered a very particular one, as it is a peat-like deposit derived from the accumulation of the belowground dead parts of the marine phanerogam Posidonia oceanica through the last 1600 years. This study represents the first attempt to explore the palaeoecologicalpotential of such deposits from a palynological point of view, and has allowed the reconstruction of the vegetation dynamics and changes, human impact and the palaeoclimatic characteristics, demonstrating the value of these sedimentary records in palaeopalynological studies., This work was supported by the PALEOMED and CARBOMED projects, respectively funded by the Spanish Ministry of Science and Technology (McyT-BOS2002-02247) and the Spanish National Research Council (CSIC) (PIF-CSIC 20050F0231). LLM has benefited from a CSIC-ESF research contract (I3P predoctoral program).

The palynological record of Puerto de Serranillos provides insights into the late Holocene vegetation history of Sierra de Gredos in the Central Mountain System of the Iberian Peninsula. Overgrazing around the timberline has occurred at least throughout the past two millennia, related to the human management of the landscape. Before the 12th century AD, Pinus sylvestris forests were dominant with a diversity of accompanying trees and understorey. The current landscape of the Gredos Range is clearly anthropogenic, and includes a combination of forest patches, pastures, dense shrubby formations and prostrate junipers, overall generated during the transition between the 17th and 18th centuries AD, when continued human activity in the mountain pine forests, using fire and intensifying grazing practices, caused a progressive deforestation, and the expansion of the current fire-prone scrub. © 2009 Elsevier B.V. All rights reserved., We are indebted to the Spanish Consolider Program (CSD2007-00058), HAR2008-06477-C03-03/HIST and CGL-2006-2956-BOS projects (Plan Nacional de I + D + i), and Paleodiversitas Network (Fundación Séneca, Murcia) for financial and technical support. We wish to thank to Dr. Leonor Peña, Dr. Julio Escalona and Guillermo-Sven Reher for valuable suggestions, as well as Marta Fernández and Rodolfo Pozuelo for technical help. One of the authors (L. López-Merino) was supported by a CSIC-ESF research contract (I3P predoctoral program).

In this paper we present a review of the available pollen analyses in the north-western Iberian Range with the aim of studying Fagus glacial refugia and Holocene expansion. The work collects the available pollen analyses in the area (24 sites and 58 14C dates). Based on the available palynological data, we try to reconstruct the changes that occurred in the distribution of Fagus sylvatica in the north-western Iberian Range during the late Pleistocene and the Holocene, its spread patterns and the possible causes for such changes. Results from pollen analyses allow establishing at the Middle Holocene the beginnings of Fagus expansion mostly in relation to anthropic activities. Also, the pollen data demonstrate the existence of Fagus glacial refuge during the Late Pleistocene and the Early Holocene. Therefore, we hypothesize that present-day beech forests, in the area under study, are the direct result of the relic populations that survived the last glaciations and that have been favoured by both environmental conditions and human activities. © 2008 Elsevier B.V. All rights reserved., One of the authors (L. López-Merino) was supported by a CSIC-ESF (European Social Fund) research contract (I3P predoctoral program).