Anthracological evidence suggests naturalness of Pinus pinaster in inland southwestern Iberia

The study of well-preserved archaeological charcoals in the pre-Roman Iron Age settlement of Castillejos II (Badajoz, Spain) is used to reconstruct environmental conditions and land-use practices in vegetation landscapes in the southwest of the Iberian Peninsula before the arrival of Roman civilization. The results support that, while evergreen Quercus forests dominated during the Holocene, Pinus pinaster existed as a natural element of southwestern Iberian Peninsula vegetation. Although its presence could be linked to anthropogenic disturbance or fire history, it is suggested that P. pinaster populations survived during the Holocene in the region, mixed with oaks or in monospecific stands in mountain enclaves. This hypothesis contrasts with previous assumptions that P. pinaster was not autochthonous in the area

Nuevos datos de carbones y maderas fósiles de Pinus pinaster Aiton en el Holoceno de la Península Ibérica

The study of ligneous fossil remains (charcoal and wood) corresponding to three sites located in the interior of the Iberian Peninsula is presented. The chronologies established by means of radiocarbon or relative dating (archaeological) situate all the samples in the last phase of the Holocene. In the three deposits Pinus pinaster has been identified and there have being made other taxonomic contributions. A review of previous Pinus pinaster findings registered in the Peninsula is exposed and other considerations are made on the importance of this taxon in the Iberian vegetal landscape during the end of the Quaternary.Se ha realizado un estudio de restos fósiles leñosos correspondientes a tres yacimientos del interior de la península Ibérica: Hontalbilla (Segovia), Yecla (Murcia) y Castillejos (Badajoz). Las cronologías establecidas mediante datación absoluta (radiocarbono) o relativa (arqueológica) sitúan todas las muestras en la última fase del Holoceno. En los tres yacimientos se ha identificado Pinus pinaster, realizándose además otras aportaciones taxonómicas. Se reúnen los datos conocidos de macrorrestos de P. pinaster registrados en la Península y se realizan consideraciones sobre la importancia de este taxon en el paisaje vegetal ibérico durante el final del Cuaternario

Contribución de la Paleofitogeografía a la interpretación del paisaje vegetal ibérico: estado de conocimientos y nuevas perspectivas de investigación

The palaeobotanical studies that have been accomplished in the Iberian Peninsula during the last two decades have provided a great amount of data that can be applied in geobotanical knowledge. In most of the cases, those results have contributed to solve classical scientific debates regarding vegetal landscapes interpretations. One of the most relevant discussions is related to the aloctonous or non-aloctonous origin of much of the Iberian pine forests, on diverse Iberian habitats. The main contributions of Palaeobotany to the processes that explain the present distribution of plants are reviewed in a spatial and temporal framework, from old geological periods (Mesozoic, Tertiary) to the recent ones (Pleistocene, Holocene). Linked to the history of our vegetal landscapes, Pleistocene and Holocene epochs have been treated from two different points of view: firstly the problems within extensive territorial environments and, secondly, the problems related to the interpretation of the evolution and/or behaviour of taxa. In the last part, some new investigation trends related to palaeophytogeography are exposed, focusing on the high potential interest on being applied to Iberian ecosystems.Los trabajos de carácter paleobotánico realizados en la península Ibérica en las dos últimas décadas han proporcionado un importante volumen de resultados con aplicación en el ámbito del conocimiento geobotánico. En muchos casos, esos resultados han aportado soluciones a debates clásicos relativos a la interpretación del paisaje vegetal. Uno de los más conocidos es el de la consideración, como espontáneos o no, de muchos de los pinares ibéricos en diferentes ámbitos del territorio peninsular. Se revisan las contribuciones más importantes de la Paleobotánica a los procesos que explican la actual distribución de las plantas, en un marco tanto espacial como temporal, desde periodos geológicos antiguos (Mesozoico, Terciario) a los más recientes (Pleistoceno, Holoceno). Dentro de estos últimos nos hemos referido, por una parte, a problemas planteados en ámbitos territoriales extensos y, por otra, a problemas vinculados a la interpretación de la evolución y/o comportamiento de taxones concretos. Por último se hace referencia a las tendencias recientes y nuevas metodologías de aplicación en paleofitogeografía, aludiendo a los primeros resultados que hayan podido proporcionar en el marco peninsular

Negative responses of highland pines to anthropogenic activities in inland Spain: a palaeoecological perspective

Palaeoecological evidence indicates that highland pines were dominant in extensive areas of the mountains of Central and Northern Iberia during the first half of the Holocene. However, following several millennia of anthropogenic pressure, their natural ranges are now severely reduced. Although pines have been frequently viewed as first-stage successional species responding positively to human disturbance, some recent palaeobotanical work has proposed fire disturbance and human deforestation as the main drivers of this vegetation turnover. To assess the strength of the evidence for this hypothesis and to identify other possible explanations for this scenario, we review the available information on past vegetation change in the mountains of northern inland Iberia. We have chosen data from several sites that offer good chronological control, including palynological records with microscopic charcoal data and sites with plant macro- and megafossil occurrence. We conclude that although the available long-term data are still fragmentary and that new methods are needed for a better understanding of the ecological history of Iberia, fire events and human activities (probably modulated by climate) have triggered the pine demise at different locations and different temporal scales. In addition, all palaeoxylological, palynological and charcoal results obtained so far are fully compatible with a rapid human-induced ecological change that could have caused a range contraction of highland pines in western Iberia

The Helicobacter pylori Genome Project : insights into H. pylori population structure from analysis of a worldwide collection of complete genomes

Helicobacter pylori, a dominant member of the gastric microbiota, shares co-evolutionary history with humans. This has led to the development of genetically distinct H. pylori subpopulations associated with the geographic origin of the host and with differential gastric disease risk. Here, we provide insights into H. pylori population structure as a part of the Helicobacter pylori Genome Project (HpGP), a multi-disciplinary initiative aimed at elucidating H. pylori pathogenesis and identifying new therapeutic targets. We collected 1011 well-characterized clinical strains from 50 countries and generated high-quality genome sequences. We analysed core genome diversity and population structure of the HpGP dataset and 255 worldwide reference genomes to outline the ancestral contribution to Eurasian, African, and American populations. We found evidence of substantial contribution of population hpNorthAsia and subpopulation hspUral in Northern European H. pylori. The genomes of H. pylori isolated from northern and southern Indigenous Americans differed in that bacteria isolated in northern Indigenous communities were more similar to North Asian H. pylori while the southern had higher relatedness to hpEastAsia. Notably, we also found a highly clonal yet geographically dispersed North American subpopulation, which is negative for the cag pathogenicity island, and present in 7% of sequenced US genomes. We expect the HpGP dataset and the corresponding strains to become a major asset for H. pylori genomics

Estudio de los macrorrestos vegetales del yacimiento de Lomilla (Aguilar de Campoo, Palencia, España)

The discovery of a site with abundant fossil plant remains in the surroundings of Aguilar de Campoo (Palencia, Spain), dated in the early Holocene, allowed us to obtain new data on the composition of foreste in that área. Two species of <i>Pinus</i> and several broadleaved trees have been identified. A wider distribution than the current one for some of these taxa has been confirmed. The ecological requirements of these species today allow the probable Palaeoecological conditions during the Holocene to be established.<br><br>El hallazgo en las cercanías de Aguilar de Campoo (Patencia, España) de un yacimiento con abundante material vegetal fósil (maderas, cortezas, frutos), datado en el primer tercio del Holoceno, ha permitido obtener datos de interés acerca de la composición de la vegetación forestal en el área. Se han identificado dos especies del género <i>Pinus</i> y varias frondosas arbóreas. Se ha observado un área de distribución más extensa que la actual para varios de estos táxones. Los requerimientos ecológicos de los táxones encontrados en este yacimiento permiten establecer algunas de las características paleoambientales que probablemente tuvo este territorio durante el período considerado

Nuevos datos de carbones y maderas fósiles de Pinus pinaster Aiton en el Holoceno de la Península Ibérica

Se ha realizado un estudio de restos fósiles leñosos correspondientes a tres yacimientos del interior de la península Ibérica: Hontalbilla (Segovia), Yecla (Murcia) y Castillejos (Badajoz). Las cronologías establecidas mediante datación absoluta (radiocarbono) o relativa (arqueológica) sitúan todas las muestras en la última fase del Holoceno. En los tres yacimientos se ha identificado Pinus pinaster, realizándose además otras aportaciones taxonómicas. Se reúnen los datos conocidos de macrorrestos de E pinaster registrados en la Península y se realizan consideraciones sobre la importancia de este taxon en el paisaje vegetal ibérico durante el final del Cuaternario