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In around 716 AD, the city of Santarém, Portugal, was conquered by the Berber and Arab armies that swept the Iberian Peninsula and went on to rule the region until the 12th century. Archaeological excavations in 2007/08 discovered an Islamic necropolis (Avenida 5 de Outubro #2–8) that appears to contain the remains of an early Muslim population in Santarém (8th– 10th century). In this study, skeletal material from 58 adult individuals was analysed for stable carbon (δ13Ccol; δ13Cap), nitrogen (δ15N) and sulphur (δ34S) isotope ratios in bones, and stable oxygen (δ18O), carbon (δ13Cen) and radiogenic strontium (87Sr/86Sr) isotopes in tooth enamel. The results of this study revealed a dietary pattern of predominantly C3-plant and domestic C3-fed herbivore consumption during adulthood (δ13Ccol and δ15N, respectively) but a higher proportion of C4-plant input during childhood (δ13Cen) for some individuals—interpreted as possible childhood consumption of millet porridge, a common practice in North Africa—in those with unorthodox burial types (Groups 1 and 2) that was not practiced in the individuals with canonical burials (Group 3). In this first mobility study of a medieval Muslim population in Portugal, δ18ODW values revealed greater heterogeneity in Groups 1 and 2, consistent with diverse origins, some in more humid regions than Santarém when compared to regional precipitation δ18O data, contrasting the more homogenous Group 3, consistent with the local precipitation δ18O range. Ancient DNA analysis conducted on three individuals revealed maternal (mtDNA) and paternal (Y-chromosome) lineages compatible with a North African origin for (at least) some of the individuals. Additionally, mobility of females in this population was higher than males, potentially resulting from a patrilocal social system, practiced in Berber and Arab communities. These results serve to offer a more detailed insight into the ancestry and cultural practices of early Muslim populations in Iberia. [ABSTRACT FROM AUTHOR]

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Post-collisional potassium-rich rocks are a critical petrogenetic and geodynamic marker across the European Variscan Belt. We present a detailed characterization of the only potassium-rich mafic intrusions identified so far in the Ossa-Morena Zone (Iberian Massif). Using new major, trace and Sm Nd isotopic whole-rock analyses, as well as mineral chemistry analyses, we discussed the petrogenesis of the early Carboniferous potassium-rich Veiros and Vale de Maceira (Portugal) stocks in the geotectonic framework of the southern Iberia, marked by the collision of the Ossa-Morena Zone, a Gondwanan terrane, with the South Portuguese Zone, a Laurussian terrane. The Veiros and Vale de Maceira shoshonites (s.l.) range from gabbros to syenites, with a predominance of monzonites and monzogabbros, characterized by different proportions of olivine, clinopyroxene, orthopyroxene, plagioclase, alkali feldspar, phlogopite and brown hornblende. The Veiros stock is mainly composed of fine-grained ultrapotassic rocks, and the Vale de Maceira stock is composed chiefly of medium-grained shoshonite rocks. A small group of hornblende-bearing medium-grained calk-alkaline rocks was also identified. The stocks have high contents of K 2 O, MgO, total alkalis, Th and other LILE, high ratios of LREE/HREE and LREE /HFSE, and show a Nb-Ta-Ti negative anomaly, typical of orogenic settings. Sr and Nd isotopes yielded moderate radiogenic Sr and unradiogenic Nd, that might suggest the involvement of a crustal component. However, the combined use of isotopic and elemental compositions rules out significant contamination by crustal materials upon ascent and emplacement. Instead, a source metasomatised by subduction-related fluids and hydrous melts from the slab is proposed. This diversely metasomatised source was a phlogopite-amphibole-bearing and (phlogopite-free) amphibole-bearing lherzolite at the upper part of the garnet stability field in the sub-continental lithospheric mantle. The Devonian mafic volcanic rocks point to a northward dipping (present coordinates) subduction of the Rheic oceanic plate underneath the Ossa-Morena Zone during the Variscan Orogeny. However, the Veiros and Vale de Maceira magmas originated during the post-collisional stage from the partial melting of the supra-subduction metasomatized lithosphere. The melting occurred during a period of enhanced heat due to asthenospheric upwelling related to the slab break-off of the Rheic's slab. The stocks are concomitant with the profusion of granitoid intrusions, which is compatible with a post-collisional tectonic setting. They are also coeval with the opening of the Beja-Acebuches back-arc, likely related to slab roll-back of a segment of the Rheic oceanic crust, implying polyphasic subduction and a complex geodynamic setting for the late stages of oceanic closure in southern Iberia. [ABSTRACT FROM AUTHOR]

The effects of hydropeaking in the habitat of the Iberian barbel ( Luciobarbus bocagei ) a native cyprinid fish species of the Iberian Peninsula, were investigated. Two study sites were selected in the Ocreza River, Mid-Eastern Portugal. A regulated site located immediately downstream from a hydropower dam, and an unregulated site located on a lotic undisturbed segment upstream the reservoir. The habitat preferences were determined based on field data collection and displayed by means of fuzzy sets and rules for juvenile and adult life-stages of barbel. The River2D and CASiMiR Fish 2D model were applied to both river sites in the Ocreza River to simulate how physical habitat conditions vary with powerhouse operation. Results indicate that hydropeaking impact is strongly dependent on river morphology. The more heterogeneous the river is the better it can support areas of suitable habitat, including shelters. Whatsoever, stranding is an associated risk. Furthermore, shifts in the array of habitats were due to occur between the base and peak flow. The study outcomes provide comprehensive information on the barbel response to hydropeaking. Understanding how hydropeaking influences both habitat availability and population dynamics is a crucial point to help guiding hydropower managers towards more sustainable practices. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the first results of ice rafted detritus (IRD) provenance related to Heinrich Events in the NW Iberian Margin are presented and discussed. This study is based on multi-proxies, namely on thorough analyses of Sr and Nd isotope ratios measured in the detrital fraction of the sediment core KC 024-19, from the Galician continental slope (NE Atlantic), aiming to unravel the sources of the terrigenous component of the sampled sediments. In most of the core layers, the isotope signatures are consistent with an origin, ultimately, in the nearby Variscan continental crust. However, allochthonous contributions were also deposited, namely during the last four Heinrich Events (HE). The non-carbonate detrital fraction of the sediments deposited during the HE1 (in its upper part), HE2, and HE4 displays ɛ Nd much lower than usual, suggesting that those layers incorporate clasts dropped by icebergs (Ice-Rafted Detritus – IRD) whose sources must have been located in Archaean cratons, such as those of northeastern America and Greenland. The low-ɛ Nd values combined with dolomite peaks support the hypothesis that icebergs fed by the Laurentide ice sheet and launched through Hudson Strait played a major role in the deposition of IRD during HE1, HE2, and HE4. The HE1 layer seems to record a complex evolution of this event, since, at its base, the coarse-grained non-carbonate fraction displays relatively high-ɛ Nd values, pointing to European/Icelandic sources for the icebergs in the initial stages of HE1. The IRD content of the HE3 contrasts significantly with the other HE layers and the non-IRD layers because it has an isotope signature characterized by low 87Sr/86Sr ratios and high-ɛ Nd values. This suggests that the most exotic components of the HE3 layer may have come from East Greenland – Fram Strait and/or result from a mixture of materials from western European and more juvenile (Iceland – Faeroes) crustal sources. [Copyright &y& Elsevier]

Identifying the environmental gradients that control the functional structure of biological assemblages in reference conditions is fundamental to help river management and predict the consequences of anthropogenic stressors. Fish metrics (density of ecological guilds, and species richness) from 117 least disturbed stream reaches in several western Iberia river basins were modelled with generalized linear models in order to investigate the importance of regional- and local-scale abiotic gradients to variation in functional structure of fish assemblages. Functional patterns were primarily associated with regional features, such as catchment elevation and slope, rainfall, and drainage area. Spatial variations of fish guilds were thus associated with broad geographic gradients, showing (1) pronounced latitudinal patterns, affected mainly by climatic factors and topography, or (2) at the basin level, strong upstream-downstream patterns related to stream position in the longitudinal gradient. Maximum native species richness was observed in midsize streams in accordance with the river continuum concept. The findings of our study emphasized the need to use a multi-scale approach in order to fully assess the factors that govern the functional organization of biotic assemblages in 'natural' streams, as well as to improve biomonitoring and restoration of fluvial ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: Landscapes with open evergreen oak woodlands in Southwestern Iberian Peninsula have been subjected to a consistent oak forest loss. In these landscapes, the abandonment of traditional land management activities have been associated with major land use transformations, such as the replacement of agricultural land uses and native oak woodlands by both shrublands and fast-growing Eucalyptus and pine (Pinus pinea L.) plantations. In this study a spatially explicit approach, combining aerial photographs, geographical information systems and land cover metrics, was used to assess long-term landscape dynamics over a 50-year period. The aim was to provide interpreted quantitative information on the landscape dynamics and to determine the key roles of open farmland, shrubland and new forest plantations on the ongoing loss and fragmentation of oak woodlands. Different trends of land abandonment and intensification of land uses were found across the study areas mainly related to combination of particular socioeconomic and biophysical conditions, resulting in different types of evergreen oak forest conservation and restoration issues. A comprehensive assessment of these (biophysical and socioeconomic) change driving forces is, therefore, presented and discussed, as a baseline for future planning by setting of appropriate management, restoration and conservation strategies for oak woodlands in the studied landscapes. Although this study focused on a specific system of Southwestern Mediterranean, the methodology applied herein can be extrapolated to other comparable human-driven scattered tree systems, within cultural landscapes. [Copyright &y& Elsevier]