Fire history and human activities during the last 3300 cal yr BP in Spain's Central Pyrenees: The case of the Estany de Burg

International audienceThe study of macroscopic charcoal particles from peat bogs has led to a better understanding of climate,vegetation and fire history, and human impacts. To determine the relationship between human activities andthe role of fire events in vegetation change during the last 3300 cal yr BP, we present the results of a multiproxyapproach based on the analysis of sediment characteristics, sedimentary charcoal, organic matter andpollen, as well as historical sources. This multi-proxy research permits high resolution palaeoenvironmentaland fire history reconstruction of a mountain area located in the southern central Pyrenees (Spain). In thePyrenees, fire is typically attributed to human activities since the beginning of the Bronze Age and may becorrelated with slash-and-burn cultivation, metallurgy and pasturing activities.The data indicate a good linkage between high fire signals and Poaceae and Cerealia pollen, which reveals theimpact of agro-pastoral practices. This study also shows two periods, 2900–2650 cal yr BP and 1850–1550 calyr BP, for which higher frequencies of fire occurred, suggested by high arboreal pollen (AP) concentrations,and confirming the need for arboreal biomass to sustain fires. From the beginning of the Middle Ages, it seemsthat a change occurred in the anthropogenic use of fire, from a tool for agro-pastoral forest clearance to ameans of maintaining open spaces

Vegetation dynamics and anthropogenically forced changes in the Estanilles peat bog (southern Pyrenees) during the last seven millennia

International audienceEstanilles peat bog, located in the northeasternIberian peninsula,was studied to determine the anthropogenicchanges in the landscape over the past seven millennia. Thepollen diagram and sedimentary charcoal analyses from thissite permit us to reconstruct the landscape changes in an areaof both Mediterranean and Atlantic influence. In addition,Montarenyo ombrotrophic peat bog was studied to strengthenthe analysis of data from more recent centuries. This paperattempts a reconstruction of historical cultural landscapesusing two complementary palaeobotanical proxies (pollen andcharcoal) in high mountain environments. The macroscopiccharcoal record shows a fire signal since 7500 cal. B.P. However,the relationship between fire frequency and humanimpact is not always linear. This divergence is linked to fuelavailability and fire activity. Fire has been used repeatedly toclear ground and to maintain open areas, and has been a keytool for the management of these high mountain areas. Theintensity of use of the landscape implies the expansion ofagricultural areas into higher altitudes, including cereal cultivationabove 2,200 m a.s.l., during the Middle Ages. Thefirst clear human influence detected in the pollen percentagedata is recorded between 6000 and 7000 cal. B.P. and, untilpresent times, the greatest changes in vegetation and landscapehistory occurred during periods of particular specializationin socioeconomic activities during the Middle Ages

Wiki en la Universitat Autònoma de Barcelona. Alcance y perspectivas

Since May 2004, a group of instructors of the Universitat Autònoma de Barcelona has been involved in different experiences of innovation on higher education, within the European Space of Higher Education (ESHE), regarding the use of a wiki system to improve the teaching and learning process of students. The group has focused on the development of educational activities, mainly addressed for self-directed learning and blended learning, created to strengthen collaborative work and e-learning. The experiences of the group with the use of wiki have allowed to determine the strengths and weaknesses of using the wiki platform for higher education. Using this, the group has included some new tools in the wiki system in order to improve the teaching possibilities, especially those related to the ESHE. The work developed by the group and the interest sparked by this system within the community of the university are the starting point towards the integration of the wiki in the Campus Virtual (the institutional virtual learning support platform of the Universitat Autònoma de Barcelona), which is currently being undertaken.Desde mayo del año 2004, un grupo de profesores de la Universitat Autònoma de Barcelona ha llevado a cabo distintas experiencias docentes en educación superior enfocadas a los nuevos planes piloto definidos en el marco del Espacio Europeo de Educación Superior (EEES) basadas en la utilización del wiki, con el fin de mejorar el proceso de enseñanza-aprendizaje de los estudiantes. Se han desarrollado distintos materiales docentes para el aprendizaje autónomo y semi-presencial, diseñados para potenciar el trabajo colaborativo y a distancia. El análisis de los resultados obtenidos con la aplicación del wiki a la docencia ha permitido identificar las ventajas y las carencias del sistema de trabajo inicial y ampliar sus posibilidades con herramientas que aseguran una mejor adaptación de esta plataforma al EEES. La labor desarrollada por el grupo y el interés despertado en la comunidad universitaria son el punto de partida de la integración del wiki en el Campus Virtual (la plataforma institucional de soporte virtual del aprendizaje de la Universitat Autònoma de Barcelona) que se está llevando a cabo actualmente

Towards a stomata based atmospheric CO2 reconstruction using Pinus sylvestris and Abiesalba remains

A number of species (i.e.: Quercus, Betula, Pinus, Tsuga?), which leave/needle remains have been preserved in different deposits along the Earth and, therefore, they have been used to reconstruct past atmospheric conditions. Still, plant atmospheric responses are species and site specific, and calibration with present or recent past material is needed prior to estimate any atmospheric parameter. Recent palaeobotanical researches in the Pyrenees and in the Iberian Central System, conducted under a coordinated project funded by the Spanish Ministerio de Ciencia, Innovación y Universidades (CSO2015- 65216-C2-1-P/2-P), have given light to numerous Abies alba and Pinus sylvestris-uncinata type Late Pleistocene needle remains. Here we present the preliminary stomatal-atmospheric CO2 calibration performed on Pinus uncinata, Pinus sylvestris and Abies alba altitudinal transects sampled during 2013 and 2017 on six Pyrenean populations (Irati?Navarra, Mata de Valencia?Lérida, Virós-Lérida, Maçarent de Cabrenys?Gerona, Montseny?Barcelona), and an additional P. sylvestris Central System population (Cotos ? Madrid). Five to nine needles per altitude, sampled every 100 m altitudinal increase (from 900 to 2600 m a.s.l.) were macerated and skilled to analyse cuticle parameter (stomata density, stomatal length, stomatal band width and length and pore length) responses to CO2 atmospheric partial pressure changes

Towards a stomata based atmospheric CO2 reconstruction using Pinus sylvestris and Abiesalba remains

A number of species (i.e.: Quercus, Betula, Pinus, Tsuga?), which leave/needle remains have been preserved in different deposits along the Earth and, therefore, they have been used to reconstruct past atmospheric conditions. Still, plant atmospheric responses are species and site specific, and calibration with present or recent past material is needed prior to estimate any atmospheric parameter. Recent palaeobotanical researches in the Pyrenees and in the Iberian Central System, conducted under a coordinated project funded by the Spanish Ministerio de Ciencia, Innovación y Universidades (CSO2015- 65216-C2-1-P/2-P), have given light to numerous Abies alba and Pinus sylvestris-uncinata type Late Pleistocene needle remains. Here we present the preliminary stomatal-atmospheric CO2 calibration performed on Pinus uncinata, Pinus sylvestris and Abies alba altitudinal transects sampled during 2013 and 2017 on six Pyrenean populations (Irati?Navarra, Mata de Valencia?Lérida, Virós-Lérida, Maçarent de Cabrenys?Gerona, Montseny?Barcelona), and an additional P. sylvestris Central System population (Cotos ? Madrid). Five to nine needles per altitude, sampled every 100 m altitudinal increase (from 900 to 2600 m a.s.l.) were macerated and skilled to analyse cuticle parameter (stomata density, stomatal length, stomatal band width and length and pore length) responses to CO2 atmospheric partial pressure changes

How climate, migration ability and habitat fragmentation affect the projected future distribution of European beech

Recent efforts to incorporate migration processes into species distribution models (SDMs) are allowing assessments of whether species are likely to be able to track their future climate optimum and the possible causes of failing to do so. Here, we projected the range shift of European beech over the 21st century using a process-based SDM coupled to a phenomenological migration model accounting for population dynamics, according to two climate change scenarios and one land use change scenario. Our model predicts that the climatically suitable habitat for European beech will shift north-eastward and upward mainly because (i) higher temperature and precipitation, at the northern range margins, will increase survival and fruit maturation success, while (ii) lower precipitations and higher winter temperature, at the southern range margins, will increase drought mortality and prevent bud dormancy breaking. Beech colonization rate of newly climatically suitable habitats in 2100 is projected to be very low (1-2% of the newly suitable habitats colonised). Unexpectedly, the projected realized contraction rate was higher than the projected potential contraction rate. As a result, the realized distribution of beech is projected to strongly contract by 2100 (by 36-61%) mainly due to a substantial increase in climate variability after 2050, which generates local extinctions, even at the core of the distribution, the frequency of which prevents beech recolonization during more favourable years. Although European beech will be able to persist in some parts of the trailing edge of its distribution, the combined effects of climate and land use changes, limited migration ability, and a slow life-history are likely to increase its threat status in the near future.Frédérik Saltré, Anne Duputié, Cédric Gaucherel and Isabelle Chuin