Persistence of tree relicts in the Spanish Central System through the Holocene

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.This paper is part of the research carried our within the project "Dinámicas socio-ecológicas, resiliencia y vulnerabilidad en un paisaje de montaña: el Sistema Central (9000 cal. BC-1850 cal. AD) " (R&D National Plan of the Spanish Government, HAR2013-43701-P)

Restos de caballos fósiles cuaternarios en la depresión Prados-Guatén (Pantoja de la Sagra, Toledo)

Durante la primera reunión de campo del Grupo Madrileño de Cuaternario (GQM-AEQUA) se localizaron restos fragmentarios de dentición de caballos fósiles en los antiguos areneros de Pantoja de La Sagra (Toledo), actualmente en proceso de desmantelamiento y relleno. Ante la posibilidad de deterioro y pérdida los restos fueron recolectados y trasladados al Museo Nacional de Ciencias Naturales (CSIC, Madrid) donde se ha procedido a su análisis. Las piezas fósiles analizadas responden a un maxilar izquierdo con tres piezas dentales in situ (molares y premolares), y otras siete más aisladas. Todos los dientes aislados, junto con el fragmento de maxilar existente, corresponden a un adulto joven. Los restos fósiles se encontraban asociados a un nivel de arenas fluviales situado unos cuatro metros por debajo de la superficie de la Terraza de +15 m de la Depresión Prados-Guatén definida como un nivel perteneciente al tránsito Pleistoceno inferior-medio, del antiguo Sistema fluvial Manzanares-Guatén por Silva (1988). En concreto los niveles superiores de esta terraza han sido interpretados como resultado de la superposición de los últimos depósitos del antiguo sistema fluvial y los primeros asociados al relleno de la Depresión por tributarios de área fuente más local tras su abandono como consecuencia del proceso de captura del valle inferior del Manzanares por parte del Río Jarama al SW de la Ciudad de Madrid (Silva et al., 1988). Los caracteres morfológicos y morfométricos de las piezas dentarias permiten identificarlos como Equus ferus cf. mosbachensis cuya distribución bioestratigráfica abarca la parte final del Pleistoceno Medio (c.a. 500-200 ka B.P.). Junto a los restos fósiles aparecieron también escasos fragmentos líticos correspondientes a productos de lascado en sílex de difícil atribución tecnológica. Los restos fósiles analizados, indican que el depósito extensivo de arenas fluviales en el eje de la Depresión, culminó durante el final del Pleistoceno medio, y que la dinámica fluvial de la Depresión tras su proceso de abandono fue de hecho más activa de lo que se pensaba con la instalación de sistemas de arroyos relevantes alimentados por cabeceras locales antes del encajamiento definitivo actual de los arroyos Prados y Guatén.Peer reviewe

26. Valdeyernos, Toledo Mountains (central Spain)

This contribution was financed by Project CGL2011-30512-C02-01 of the R&D National Plan of the Spanish Government, by the Technology Research ‘Consolider’ Programme (TCP-CSD2007-00058), and by the Specific Agreement Diputación de Toledo-CSIC

Contributions to the European Pollen Database. 21. Patateros, Toledo Mountains (central Spain)

The Patateros bog (39° 35′ 50′′ N, 4° 40′ 27′′ W; 700 m above sea level [a.s.l.]) lies on the northern- slope of the‘ Sierra de La Botija’ at the northern edge of the Toledo Mountains. The peat-bog extends over an area of 300 m2. The area experiences a Mediterranean climate with dry and warm summers, in fluenced by Atlantic winds from the southwest. The average annual temperature is 14–15 °C and the annual precipitation is 600–700 mm. Precipitation is unevenly distributed through the year with maximum values during winter (Perea & Perea2008). The vegetation is a planted Pinus forest. Phytogeographically, the potential vegetation of the area is typically Mediterranean, including Quercus pyrenaica Willd. (deciduous oak) forests accompanied by Arbutus unedo L. (Peinado et al.2008). The bog vegetation is composed mainly of Sphagnum sp., Erica tetralix L. and Molinia caerulea (L.) Moench. (Velasco 1980). The bedrock is old siliceous basement made up mainly of lower Ordovician Armorican Quartzites (Moreno 1977).This contribution was financed by Project CGL2011-30512-C02-01 of the R&D National Plan of the Spanish Government, by the Technology Research ‘Consolider’ Programme (TCP-CSD2007-00058), and by the Specific Agreement Diputación de Toledo-CSIC.Peer Reviewe

A recent analogue for palustrine carbonate environments: The Quaternary deposits of Las Tablas de Daimiel wetlands, Ciudad Real, Spain

Las Tablas de Daimiel, Spain, is one of the scarce, freshwater wetlands areas still preserved in southern Europe. The wetland is fed by surface and groundwater. We studied the Quaternary sedimentary record of Las Tablas in a drill hole that penetrated 38.5 m of shallow-lake and fluvial deposits. Differences in the dominantly micritic muds indicate three main stages of development. In the lowest stage, unit A, (Lower? to Middle Pleistocene) the slightly saline wetland developed under a relatively arid climate that favored slow flow movement of the fluvial system and the disconnection of the ponded areas. In the intermediate stage, unit B, (Middle to Upper Pleistocene) extensive peat developed during wetter conditions. Biosiliceous sediments (diatoms and sponge spicules) also accumulated in this swampy setting. In the latter stage, unit C, (Upper Pleistocene to Holocene) palustrine carbonates formed in a freshwater environment with desiccation events, followed by fluvial reworking of the lake margins. Lithification of these deposits was relatively fast (≤10,000 yr). The studies of the core, including mineralogy, petrography, stables isotopes, and pollen analyses, indicate that these sediments are similar to those of ancient palustrine sequences. Therefore, Las Tablas can be considered as a recent analogue for freshwater palustrine systems that have no marine influence. These systems are very sensitive to changes in climate or base level, and their study is needed to better understand the terrestrial sedimentary record. Study is needed also to determine how to preserve these wetlands.Las Tablas de Daimiel constituyen uno de los escasos humedales de agua dulce que aún se conservan en el sur de Europa, concretamente en España. El humedal está abastecido por aguas superficiales y subterráneas. El registro sedimentario Cuaternario de Las Tablas, se ha estudiado mediante un sondeo en el que se cortaron 38.5 m de depósitos lacustres someros y fluviales, esencialmente carbonatos micríticos. Las características de los sedimentos permiten diferenciar tres principales etapas de sedimentación. En la primera etapa, unidad A, (Pleistoceno Inferior? a Medio) el humedal era ligeramente salino y se desarrolló bajo un clima relativamente árido que favoreció el flujo más lento del sistema fluvial, permitiendo la desconexión de las zonas encharcadas. En la etapa intermedia, unidad B, (Pleistoceno Medio a Superior) el amplio desarrollo de turberas indica condiciones más húmedas, en las que dentro de las áreas pantanosas también se depositaron sedimentos biosilíceos (diatomeas y espículas de esponjas). En la última etapa, unidad C, (Pleistoceno Superior a Holoceno) los sedimentos característicos son carbonatos palustres formados en un ambiente de agua dulce con eventos de desecación seguidos de posterior retrabajamiento de los márgenes lacustres por canales fluviales. La litificación de estos depósitos fue relativamente rápida (<10000 años). El estudio llevado a cabo en el sondeo (mineralogía, petrografía, isótopos estables, análisis polínicos) indica que estos sedimentos son similares a las secuencias palustres del registro geológico. Por tanto, Las Tablas de Daimiel pueden considerarse como un análogo reciente para sistemas palustres de agua dulce que no tengan influencia marina. Estos sistemas son muy sensibles a cambios climáticos y/o del nivel de base, por lo que su estudio es necesario para conocer mejor el registro sedimentario continental, pero también para preservar estos humedales.Ministerio de Educación y CienciaDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Middle Pleistocene variations in palaeoclimate, palaeoenvironment and vegetation of the Las Tablas de Daimiel National Park (Spain)

Received 15 August 2009; Revised 17 June 2010; Accepted 21 June 2010. Copyright © 2011 John Wiley & Sons, Ltd.The Middle Pleistocene palaeoclimate and palaeoenvironment evolution of the Las Tablas de Daimiel wetlands is described using a combination of sedimentology, pollen and δ13C and δ18O isotopic records of Unit B of core LT-199906. This unit mostly contains fluvial and palustrine sediments. U/Th and amino acid racemization (AAR) dating and a comparison of the δ18Ocurve of Unit B with oceanic records suggests that Unit B spans the period from the end of Marine Isotope Stage (MIS) 10 (340 ka) to the first stages of MIS 7 (ca. 210 ka). MIS 9 was characterised by a regional vegetation dominated by Cupressaceae, with Pinus as a tree element. The water level was high and temperatures were very probably higher than during the Holocene. MIS 8 and the first substages of MIS 7 (7e, 7d and 7c) were dominated by xerophilous steppe vegetation in lowlands (elevations around 610m above sea level) near to the wetland. At higher altitudes, far away from the wetland, there were fewer Pinus than in MIS 9, and a greater presence of warm, temperate and cool climate tree elements. The aquatic system in MIS 9 became shallower, with eutrophication and the accumulation of organic matter occurring; temperatures were similar to or lower than those of the Holocene.Ministerio de Educación y Ciencia (España)Ministerio de Educación y Ciencia (España)Ministerio de Educación y Ciencia (España)Ministerio de Educación y Ciencia (España)Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Millennial climate oscillations controlled the structure and evolution of Termination II

The controls that affect the structure and timing of terminations are still poorly understood. We studied a tufa deposit from the Iberian Peninsula that covers Termination II (T-II) and whose chronology was synchronized to speleothem records. We used the same chronology to synchronize ocean sediments from the North Atlantic to correlate major climate events in a common timescale. We identify two stages within T-II. The first stage started with the increase of boreal summer integrated solar insolation, and during this stage three millennial climate oscillations were recorded. These oscillations resulted from complex ocean–atmosphere interactions in the Nordic seas, caused by the progressive decay of Northern Hemisphere ice-sheets. The second stage commenced after a glacial outburst that caused the collapse of the Thermohaline Circulation, a massive Heinrich event, and the onset of the Bipolar Seesaw Mechanism (BSM) that eventually permitted the completion of T-II. The pace of the millennial oscillations during the first stage of T-II controlled the onset of the second stage, when the termination became a non-reversible and global phenomenon that accelerated the deglaciation. During the last the two terminations, the BSM was triggered by different detailed climate interactions, which suggests the occurrence of different modes of terminations.The Junta de Comunidades de Castilla-La Mancha provided the permissions to sample in Trabaque Canyon. Tis research received funding from the European Community under the Marie Curie IEF of the FP7/2007-2013 (Grant agreement no. 219891: PROCAVET project, awarded to D.D.-V.). Publication was supported by the Open Access Publication Fund of the University of Zagreb Faculty of AgriculturePeer reviewe

Landscape and climatic changes during the end of the Late Prehistory in the Amblés Valley (Ávila, central Spain), from 1200 to 400 cal BC

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.Peer Reviewe