Evolución de los bosques en la costa Atlántica ibérica durante el Cuaternario. Implicaciones paleoclimáticas

Con el objeto de profundizar en el conocimiento sobre la composición y dinámica del paisaje vegetal de la costa Atlántica ibérica durante el último ciclo glaciarinterglaciar, se han muestreado 18 yacimientos, de los que se han extraído 228 maderas, 50 frutos y más de 350 restos foliares. Estos restos fueron identificados mediante su estudio morfológico y anatómico, y datados mediante la asignación cronoestratigráfica basada en la medición del 14C de restos leñosos. Estos datos permitieron, gracias a las propiedades de los macrorrestos, deducir el paisaje que existió en las costas ibéricas desde la desembocadura del río Tajo hasta el Golfo de Vizcaya, desde hace 34000 años hasta la actualidad. Igualmente, se ha podido afirmar el carácter autóctono de algunos taxones en la costa Atlántica ibérica, y reconocer la importancia de esta área como refugio para distintos taxones en momentos glaciares. Adicionalmente, el conocimiento de la presencia de ciertas poblaciones en el pasado ha permitido estimar las condiciones paleoclimáticas en la costa Atlántica ibérica. Igualmente, el estudio anatómico de los restos foliares ha informado sobre las condiciones atmosféricas del momento en el que se desarrollaron. Estas condiciones, principalmente la concentración del dióxido de carbono, afectan a distintos parámetros epidérmicos, como la frecuencia y dimensión de los estomas. El estudio anatómico de numerosos restos foliares de Quercus robur en la costa septentrional de la Península Ibérica, ofreció la posibilidad de conocer la evolución del CO2 atmosférico a lo largo de los últimos 10000 años. Para ello se desarrolló un modelo, a partir de pliegos de herbario recolectados a lo largo del siglo pasado, que relaciona la frecuencia estomática de Q. robur-petraea ibéricos con la concentración atmosférica del CO2. Este modelo ha sido validado para un rango de CO2 específico (295-330 ppmv), y para poblaciones ubicadas a menos de 1000 m sobre el nivel del mar. La comparación de dicho modelo con el existente, de aplicación en poblaciones de Q. robur-petraea holandeses, permitió proponer un modelo común para poblaciones europeas de Q. robur-petraea por debajo de 1000 m sobre el nivel del mar. Por último, el conocimiento de la evolución del CO2 atmosférico a lo largo del Holoceno, en comparación con los registros disponibles de paleotemperatura, ha permitido distinguir el importante papel de este gas invernadero en la dinámica climática de los últimos 10000 años

A taxonomic tool for identifying needle remains of south-western European Pinus species of the Late Quaternary

This work provides a tool whereby the needle remains of native, south-western European Pinus spp. can be easily identified from species-specific epidermal features. To construct this tool, the needles of P. uncinata, P. sylvestris, P. nigra, P. pinaster, P. pinea and P. halepensis were gathered across the Northern Hemisphere range of each taxon and compared with non-indigenous trees growing in two South Australian Botanic Gardens. Three needles from each of these species were taken from three adult trees growing at three different localities. Light microscopy was used to observe the key epidermal and stomatal features of the needles. To improve interpretation, additional scanning electron microscopy samples were prepared. Epidermal features, including variation in the diameter of the epistomatal chamber aperture (pore), are described. A taxonomic key based on the size, shape and arrangement of the subsidiary cells of the stomatal complexes was constructed. This key enables the identification of pine needle fragments at the species level (except those belonging to the group P. gr. nigra-uncinata). Despite their overlapping range, pore size was helpful in distinguishing between P. nigra and P. uncinata and between three groups of species. Isolated stomata were also observed. Cluster and discriminant analyses of stomatal variables described in earlier studies were performed. Overlap in guard cell variables hampers species-level identification of isolated stomata. Species discrimination is improved if groups of ecological affinity are considered

Application of the biomization technique in the Eastern Colombian Andes

Two pollen records (Lake Fuquene and Pantano de Martos) are analyzed in order to test the usefulness of the Biomization technique to management on forest adaptation to climate change. This work focuses on Biomes and Plant Functional Types response to climate changes on specific dates (18, 14, 12.5, 8 and 6 Kyr) along the Late Quaternary, as deduced from the pollen composition. Results show different responses of vegetation to changes in past environmental conditions, which can be attributed to the different altitudes of the two study sites. While biomes in Lake Fuquene (2500 m a.s.l.) shift from Cool Grassland at 18 Kyr to Cool Mixed Forest and Cool evergreen Forest at 6 Kyr ago, no biome shift is detected in Pantano de Martos (3200 m a.s.l.) through the Late Quaternary. A look to the different Plant Functional Types taking part on the surroundings of the study sites at different ages, together with the analyses of Arboreal / Non Arboreal pollen percentages, give a detailed idea of the ecosystem response to past climate changes. This study shows the potential of the Biomization technique as a simple and powerful tool to analyze ecosystem responses at local and regional scales

Pleistocene-Holocene P. nigra traces on tufa archives in the Northern Meseta of the Iberian Peninsula

Molds preserved on travertines constitute exceptional species-informative material to reconstruct past vegetation. These are common on the High Ebro region. Here, the fluvial system erosion and karstification of the Mesozoic limestone since the Late Tertiary, origins extensive travertine complexes like the one studied in Tubilla del Agua (Burgos). In this site, three different travertine complexes are observed. The older one is represented by two disconnected edifices incised by the Valoria river. The age of this structure is established between > 300,000 and 240,000 yr BP, as from the U/Th dating on its base and top. The subsequent incision lasted until at least 90,000 yr BP, when another edifice erected upstream on the older one. The second travertine group comprises three platforms aged 60,000 yr BP the lower one, and 18,000 yr BP the middle one. The third travertine group is a lake-barrier complex 12,000 yr BP old, on which Tubilla del Agua was built, and a stratified travertine body that covers the valley bottom 10,000 to 2700 cal yr BP old. Some of the ages of the oldest travertines, and the most modern ones, coincide with the principal travertine formation cycles described by Durán (1996) for Spain. The matrix of precipitated calcium carbonate of all these complexes are rich in plant remain molds (mosses, stems, leaves, cones) of the surrounding flora. Pinus nigra Arnold cone molds have been localized and identified by comparative morphology studies. These remains are of high valuable information about the Pleistocene and Holocene presence of this taxon, in a site where no natural presence can be found today. This work was funded by project CGL2008-06005

A taxonomic tool for identifying needle remains of south-western European Pinus species of the Late Quaternary

Primer trabajo a nivel mundial sobre la diferenciación de especies de Pinus con clave dicotómica a través de la estructura cuticula

Taxonomic differences between Pinus sylvestris and P. uncinata revealed in the stomata and cuticle characters for use in the study of fossil material

Taxonomic differences in the needle epidermis characteristics of Pinus sylvestris L. and Pinus uncinata Ramond ex DC. from two Iberian populations were sought; such information could help identify these species when pollen analysis and the inspection of wood anatomy fails. The features of the cuticle are commonly well preserved in the fossil record. Although the epidermal patterns of the examined taxa were similar, qualitative differences were seen in the subsidiary and guard cells. P. sylvestris showed small subsidiary cells homogenously arranged around the opening of the epistomatal chamber, while P. uncinata showed small, lateral subsidiary cells and non-differentiated subsidiary cells in the polar position. The aperture of the epistomatic chamber of P. uncinata was also larger in diameter (15.1 ± 1.8 µm P. sylvestris; 21.1 ± 2.8 µm P. uncinata). Principal components analysis and discriminant analysis was performed on the features of the guard cells characterising the size and shape of the cuticular thickenings — all the variables analysed can be measured in disperse stomata in microscope preparations for pollen analysis. Significant differences were found in the upper woody lamellae width and the coefficient associated with the shape of the medial lamellae borders (discriminant analysis weighting 0.739 and 0.826 respectively). Other significant parameters included the coefficient associated with the relative size of the medial lamellae border width of the guard cells with respect to the distance between the external limits of the medial lamellae borders, and the length of the upper woody lamella. Different light regimens appeared not to significantly affect the variability of the studied features

Proyecto Docente Investigador : Botánica Forestal. Botánica, Dendrología y Geobotánica”

El presente documento constituye el Proyecto Docente e Investigador elaborado por Ignacio García-Amorena Gómez del Moral para optar a la plaza de Profesor Contratado Doctor a tiempo completo (código 0024; área de conocimiento: Ingeniería Agroforestal), adscrita al Departamento de Silvopascicultura de la Universidad Politécnica de Madrid. Este documento está basado en una amplia bibliografía consultada, así como en las experiencias propias en el campo profesional como gestor, investigador y docente universitario. En el primer capítulo se presentan unas reflexiones sobre la historia de la carrera de Ingeniería de Montes y el papel de la Botánica en la misma. Con objeto de proporcionar un marco de referencia al lector en relación con las herramientas y contenidos que se proponen, se incluye un breve resumen sobre la evolución de la botánica sistemática y geobotánica. El resto del documento se divide en dos partes. La primera de ellas hace referencia al proyecto docente. La segunda al investigador. En el proyecto docente se presenta en primer lugar un marco conjunto a las dos asignaturas objeto de la plaza. Este marco hace referencia a la formación e intereses de los alumnos que entrarán en la Escuela, a las salidas profesionales de las distintas titulaciones, a los planes de estudio y a los recursos didácticos de los que se podrá hacer uso. A continuación se presenta la descripción de cada asignatura y las respectivas propuestas sobre los métodos de enseñanza, contenidos, programas y sistemas de evaluación. En la parte correspondiente a la investigación, se presentan los fundamentos que han de regir la tarea investigadora del profesor universitario, haciendo especial incidencia en la vertiente investigadora en los campos específico y docente. Tras exponer el papel del profesor en el marco de la tercera misión de la Universidad (la transferencia), finaliza este apartado con la integración de la tarea investigadora y docente del profesor universitario en un marco más amplio. Finalmente, cierra el documento un anexo donde se presenta un proyecto científico concreto

Time series analysis of long term palaeoecological records for the understanding climate change impacts on vegetal ecosystems

Manejo de datos paleoplinológicos a escala europea para generación de modelos climáticos continentale

Floating millenial chronologies of Pinus in the Sierra de Gredos (Spain)

This research has been carried out by some members of the “History and Dynamics of the Vegetal Landscape” Research Group of the Technical University of Madrid (Spain). The team has been working on the flora, vegetation and dendrochronology of the Sierra de Gredos (Ávila, Spain) for the last 20 years. Recently, we have implemented a new research field focused on the study of megafossils. All this data set has allowed us to develop an interpretation of the dynamics of mountain pine forests in this region

The past distribution of pinus nigra arnold in northern iberia. Contribution from its macroremains.

The presence of Pinus nigra in central Spain, where its natural populations are very rare, has led to different interpretations of the current vegetation dynamics. Complementary to the available palynological evidence, macroremains provide local information of high taxonomic resolution that helps to reconstruct the palaeobiogeography of a given species. Here we present new macrofossil data from Tubilla del Lago, a small palaeolake located at the eastern part of the northern Iberian Meseta. We identified 17 wood samples and 71 cones on the basis of their wood anatomy and morphology, respectively. S ome of the fossil samples were radiocarbon dated (~4.230-3210 years cal BP). The results demonstrate the Holocene presence of P. nigra in the study area, where it is currently extinct. This evidence, together with other published palaeobotanical studies, indicates that the forests dominated by P. nigra must have had a larger importance on the landscape prior to the anthropogenic influence on the northern Iberian Meseta