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Pollen, non-pollen palynomorphs and charcoal from a colluvial soil surrounded by prehistoric petroglyphs (Campo Lameiro, NW Spain) were studied in order to assess the nature of human activities and their impact on Holocene vegetation patterns. Several phases of anthropogenic impact were observed. (i) Between 7.6 and 6.5 ka cal BP, synanthropic taxa (Urtica dioica type, Plantago lanceolata type) and coprophilous fungi (e.g. Sporormiella-type) are indicative of early (pre-agricultural) creation of small patches of pasture using fire, possibly for incipient animal husbandry or as part of a deliberate strategy to improve game availability. Such activities only had a minor effect on the deciduous Quercus-dominated forest established earlier during the Holocene Thermal Maximum. (ii) Between 5.9 and 4.8 ka cal BP a more intense signal indicative of pastoral activity was detected, corresponding to the Neolithic period. (iii) Between 4.8 and 3.4 ka cal BP, which fits within the hypothetical timeframe of petroglyph creation, the synanthropic and humidity (e.g. Cyperaceae, Mougeotia) indicators diminished while charcoal concentration increased, which can be explained by Mid-Holocene cooling/drying (Neoglaciation) in combination with reduced human impact, or by non-pastoral activities in the area possibly in association with the development of the rock art culture, converting pasture to protected open ground through anthropogenic fires. (iv) During the Late Bronze Age and Early Iron Age (3.4–2.5 ka cal BP), grazing pressure and fire regime intensity are high, coinciding with evidence of regional forest regression, despite an amelioration in climate. (v) Later phases, not corresponding to prehistoric rock art contexts, include a phase of heavy grazing and reduced fire frequency (from ca. 2.5 to 1.2 ka cal BP) as well as the near complete elimination of the deciduous woodland, the expansion of ericaceous shrubland and the evidence of local agriculture and afforestation. These results are consistent with earlier studies in the area and highlight the spatial heterogeneity in the vegetation especially during periods of prehistoric anthropogenic interference., This research was supported financially by the Spanish Ministry of Science and Education under the framework of the CONSOLIDER-INGENIO 2010 program “Programa de Investigación en Tecnologías para la conservación y valorización del Patrimonio Cultural (TCP)” (CSD2007-00058) and by “Paleopaisaje y prehistoria del Futuro Parque de Arte Rupestre de Campo Lameiro, Pontevedra” (PGIDT02CCP60601).

30 páginas, 3 figuras., [ES] El sector abulense de la Sierra de Gredos constituye uno de los paisajes culturales más valiosos de la Península Ibérica, en el cual la trascendencia de la trashumancia ha jugado un papel fundamental en la configuración de sus ecosistemas desde la Prehistoria reciente hasta la actualidad. En este trabajo se analiza la evolución diacrónica de la vegetación del Puerto de Serranillos durante el Holoceno reciente, a través del registro paleopalinológico, desde la perspectiva de su ecología histórica relacionada tanto con la dinámica antrópica como paleoclimática., [EN] The Avilan sector of the Gredos Mountain Range represents one of the Iberian Peninsula’s most valuable cultural landscapes. From Prehistory to the present, the importance of trashumance in this region has played a key role in shaping its ecosystyems. Using pollen analysis to examine historical transformations in the region’s ecology, both those engendered by human activity and those relating to palaeoclimatic dynamics, this paper examines the diachronic evolution of the vegetation of the Serranillos Mountain Pass during the Late Holocene.

A series of samples extracted from the stratigraphic profile of a possible cultivation terrace located in the surroundings of an Iron Age hillfort in Galicia were used for pollen analysis. The combined results of both the stratigraphic information and the pollen analysis allow the proposal of a sequence of landscape transformation where, rather unexpectedly, the greater intensification in the use of the area, corresponding to the occupation of the hillfort and the construction of cultivation structures, coincides with an increase in the forested areas in the environment. However, the results of the analysis also document the construction of a landscape in which the effects of human action are progressively more visible.Se presentan los resultados de una caracterización palinológica realizada en un perfil en el cual se ha identificado una probable estructura de cultivo artificial (terraza) de finales de la Edad del Hierro, asociada a un castro en Galicia. El análisis combinado de las evidencias estratigráficas y palinológicas permite proponer una secuencia de transformación del paisaje en la que, de forma poco esperable, la mayor intensificación en el uso de la zona, correspondiente a la ocupación del castro y el desarrollo de estructuras agrarias, coincide con un episodio de incremento de los espacios forestales en el entorno. Sin embargo, el análisis realizado permite documentar la progresiva construcción de un paisaje cada vez más antropizado y donde los efectos de la acción humana se van haciendo más visibles.

Homenaje a Ignacio Barandiarán Maestu / coord. por Javier Fernández Eraso, Juan Santos Yanguas [ES] El estudio palinológico de los yacimientos arqueológicos de Abauntz, Aizpea y Zatoya junto con el de las turberas de Atxuri, Belate, Quinto Real y Artxilondo, aporta información sobre los primeros indicios del impacto humano en el paisaje de los Pirineos navarros. Durante el Neolítico antiguo, los procesos de deforestación fueron poco significativos, aumentando sus repercusiones durante el V milenio cal BC. Desde este período, los procesos de antropización son mucho más marcados, posiblemente como consecuencia de diferentes formas de explotación del medio (ganadería y agricultura). [EN] The palynological research of the archaeological sites of Abauntz, Aizpea and Zatoya, with those of the peat-bogs of Atxuri, Belate, Quinto Real and Artxilondo contribute information on the first indications of the human impact in the landscape of the Western Pyrenees (Navarra, Spain). During the Early Neolithic, the deforestation processes were not very significant, but they are going to increase their impact during the V millennium cal BC. After this period, the anthropic processes are much more marked, possibly as a consequence of exploitation of the environment in different ways (cattle farming and agriculture).

There is a wealth of studies dealing with the reconstruction of past environmental changes and their effects on vegetation composition in NW Iberia, but none of them have focused specifically on the post-disturbance dynamics (i.e. the type of response) of the vegetation at different space and time scales. To fill this gap, we analysed the record of pollen and non-pollen palynomorphs (NPP) of a 235-cm thick colluvial sequence spanning the last ~13,900years. The aims were to detect the changes in vegetation, identify the responsible drivers and determine the type of responses to disturbance. To extract this information we applied multivariate statistical techniques (constrained cluster analysis and principal components analysis on transposed matrices, PCA tr) to the local (hydro-hygrophytes and NPP) and regional (land pollen) datasets separately. In both cases the cluster analysis resulted in eight local and regional assemblage zones, while five (local types) and four (regional types) principal components were obtained by PCA tr to explain 94.1% and 96.6% of the total variance, respectively. The main drivers identified were climate change, grazing pressure, fire events and cultivation. The vegetation showed gradual, threshold and elastic responses to these drivers, at different space (local vs. regional) and time scales, revealing a complex ecological history. Regional responses to perturbations were sometimes delayed with respect to the local response. The results also showed an ecosystem resilience, such as the persistence of open Betula-dominated vegetation community for ~1700years after the onset of the Holocene, and elastic responses, such as the oak woodland to the 8200calyr BP dry/cold event. Our results support the notion that palaeoecological research is a valuable tool to investigate ecosystem history, their responses to perturbations and their ability to buffer them. This knowledge is critical for modelling the impact of future environmental change and to help to manage the landscape more sustainably. © 2012 Elsevier B.V., Lourdes López-Merino is currently supported by a post-doctoral research grant of the Spanish Government at Brunel University (UK). This work was funded by the projects CDS2007-00058 and PGIDT02CCP60601.

12 páginas, 5 figuras., [ES] Se presentan los resultados de una caracterización palinológica realizada en un perfil en el cual se ha identificado una probable estructura de cultivo artificial (terraza) de finales de la Edad del Hierro, asociada a un castro en Galicia. El análisis combinado de las evidencias estratigráficas y palinológicas permite proponer una secuencia de transformación del paisaje en la que, de forma poco esperable, la mayor intensificación en el uso de la zona, correspondiente a la ocupación del castro y el desarrollo de estructuras agrarias, coincide con un episodio de incremento de los espacios forestales en el entorno. Sin embargo, el análisis realizado permite documentar la progresiva construcción de un paisaje cada vez más antropizado y donde los efectos de la acción humana se van haciendo más visibles., [EN] A series of samples extracted from the stratigraphic profile of a possible cultivation terrace located in the surroundings of an Iron Age hillfort in Galicia were used for pollen analysis. The combined results of both the stratigraphic information and the pollen analysis allow the proposal of a sequence of landscape transformation where, rather unexpectedly, the greater intensification in the use of the area, corresponding to the occupation of the hillfort and the construction of cultivation structures, coincides with an increase in the forested areas in the environment. However, the results of the analysis also document the construction of a landscape in which the effects of human action are progressively more visible.

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).

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).

Many studies on ecosystem resilience often lack sufficiently long time scales to determine potential cycles of landscape response. In this paper we review some examples on how palaeoecology has provided an important aid to modern ecology in understanding ecosystem resilience. We focus some of these ideas on two Holocene sites from Southern Spain (Zonar and Gador) where current plant diversity is very high. Both sites presented resilient pattern at centennial and millennial time scales with several stable phases. Vegetation in Zonar proved to be very sensitive to environmental changes, especially moisture availability while forest in Gador responded elastically to fire and drought to a threshold level when the forest recede to a more open landscape. We conclude that any serious attempt to understand ecosystem resilience should include the long-term perspective., G. Gil-Romera is funded by the AHRC (UK) under its ‘Landscape and Environment Programme’ (award no. A/H E510590/1) and by the Spanish Ministry of Science and Innovation through the “Juan de la Cierva” program. This research has been partially funded by the projects CGL- 2006-2956-BOS, IBERVELD, CALIBRE CGL2006-13327- C04-01 and HAR2008-06477-C03-03/HIST from Ministerio de Ciencia e Innovación (Spain); CSD2007-00058 and GRACCIE CSD2007-00067 from Consolider Program of the Ministerio de Ciencia e Innovación (Spain), and ECOCHANCE and Paleodiversitas Network from Fundación Séneca (Murcia, Spain)

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).