7 resultados para HISTORY OF THE IBERIAN PENINSULA

em Repositório Científico da Universidade de Évora - Portugal


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Describing the genetic patterns and the demographic history of expanding species is essential for providing insights into the processes linked with range dynamics. We analysed the mitochondrial diversity of the Egyptian mongoose (Herpestes ichneumon) across the Iberian Peninsula, where the species is currently expanding northwest. A total of 242 individuals were analysed, together with nine representatives from the North African dispersal source. Haplotype segregation and strong differentiation between Iberian and North African populations confirmed the longterm presence of the species in the Iberian Peninsula. The distribution of mitochondrial diversity fitted the pattern of a historically diversified population in southern Iberia, from which the recent dispersals into northern areas may have occurred. Higher levels of haplotype and nucleotide diversities in the northern areas, together with the heterogeneous distribution of pairwise population differentiations and the weak signal for isolationbydistance suggest the existence of longdispersal migrants across the Iberian Peninsula. Sudden and spatial expansion scenarios of H. ichneumon in the Iberian Peninsula were supported by mismatch analysis and marginally supported by neutrality tests. However, the precise time of occurrence of the detected expansion remains unclear. Future studies should incorporate additional markers in order to further clarify the population dynamics of the Egyptian mongoose in its Iberian range.

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A climate study of the incidence of downward surface global solar radiation (SSRD) in the Iberian Peninsula (IP) based primarily on ERA-40 reanalysis is presented. NCEP/NCAR reanalysis and ground-based records from several Portuguese and Spanish stations have been also considered. The results showthat reanalysis can capture a similar inter-annual variability as compared to ground-based observations, especially on a monthly basis, even though annual ERA-40 (NCEP/NCAR) values tend to underestimate (overestimate) the observations with a mean relative difference of around 20Wm–2 (40Wm–2). On the other hand, ground-based measurements in Portuguese stations during the period 1964–1989 show a tendency to decrease until the mid-1970s followed by an increase up to the end of the study period, in line with the dimming/brightening phenomenon reported in the literature. Nevertheless, there are different temporal behaviours as a greater increase since the 1970s is observed in the south and less industrialized regions. Similarly, the ERA-40 reanalysis shows a noticeable decrease until the early 1970s followed by a slight increase up to the end of the 1990s, suggesting a dimming/brightening transition around the early 1970s, earlier in the south and centre and later in the north of the IP. Although there are slight differences in the magnitude of the trends as well as the turning year of the dimming/brightening periods, the decadal changes of ERA-40 fairly agree with the ground-based observations in Portugal and Spain, in contrast to most of the literature for other regions of the world, and is used in the climatology of the SSRD in the study area. NCEP/NCAR reanalysis does not capture the decadal variations of SSRD in the IP. The results show that part of the decadal variability of the global radiation in the IP is related to changes in cloud cover (represented in ERA-40).

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In the last three decades, the range of the Egyptian mongoose (Herpestes ichneumon) has increased in the Iberian Peninsula. A panel of microsatellites was used to confront the patterns of genetic diversity of the species with the scenario of its recent northward expansion in its Iberian range. Evidence of substructure and significant genetic differentiation within the studied population were recorded, with a central-northern subpopulation (CNorth) and a southern subpopulation (S). Northward range expansion was supported by the observed allelic frequencies, diversity parameters, and observed heterozygosity of the studied loci, with S showing a higher allelic diversity and a higher number of private alleles than CNorth. Patterns of isolation-by-distance and isolation-by-barrier as a result of the Tagus River were demonstrated, suggesting that the river acted as a semi-permeable barrier, possibly leading to genetic differentiation of the studied population. The observed individuals from CNorth in southern locations and individuals from S in central/northern areas might comprise evidence for long range dispersals across the studied range. A bottleneck event after population expansion was supported by a significant heterozygosity deficiency in CNorth, which is in agreement with a scenario of founder events occurring in recently colonized areas after the crossing of the Tagus River.

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Anglers are a recognized vector for invasive fauna, with both intentional and accidental introductions reported worldwide. * The purpose of this study was to investigate the Iberian freshwater angler's habits and perceptions related to biological invasions, using an international and bilingual survey in Spain and Portugal. * The results showed that anglers from both countries cover great distances to fish, and that they commonly visit several places and fish during consecutive days, representing a major risk for invasions. Yet, anglers' activity patterns throughout the year are not constant: the summer months involve more intense activity and, hence, entail higher risk. * In both countries, the preferred fish species were invasive, and their introductions were reported more often than native species, with motivations being country-dependent. * The use of live bait was not frequent, but sometimes invasive species were used and the release of unused bait in the water was reported very frequently. * Most anglers recognize that introductions have environmental impacts and that anglers have an active role in intentional introductions. However, only a minority is aware of the angler's role in accidental transportation of invasive species. * These findings on anglers' behaviour patterns and perceptions may be used to model invasion risks and also improve monitoring and awareness programmes led by government agencies.

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We used the results of the Spanish Otter Survey of 1994–1996, a Geographic Information System and stepwise multiple logistic regression to model otter presence/absence data in the continental Spanish UTM 10 10-km squares. Geographic situation, indicators of human activity such as highways and major urban centers, and environmental variables related with productivity, water availability, altitude, and environmental energy were included in a logistic model that correctly classified about 73% of otter presences and absences. We extrapolated the model to the adjacent territory of Portugal, and increased the model’s spatial resolution by extrapolating it to 1 1-km squares in the whole Iberian Peninsula. The model turned out to be rather flexible, predicting, for instance, the species to be very restricted to the courses of rivers in some areas, and more widespread in others. This allowed us to determine areas where otter populations may be more vulnerable to habitat changes or harmful human interventions. # 2003 Elsevier Ltd. All rights reserved.

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The Late Variscan deformation event in Iberia, is characterized by an intraplate deformation regime induced by the oblique collision between Laurentia and Gondwan. This episode in Iberia is characterized by NNE-SSW strike-slip faults, which are considered by the classic works as sinistral strike-slips. However, the absence of Mesozoic formations constraining the age of this sinistral kinematics, led some authors to consider it as the result of Alpine reworking. Structural studies in Almograve and Ponta Ruiva sectors (SW Portugal), not only shows that NNE-SSW faults presents a clear sinistral kinematics and are occasionally associated with E-W dextral shears, but also that this kinematics is related to the late deformation episodes of Variscan Orogeny. In Almograve sector, the late Variscan structures are characterized by NNE-SSW sinistral kink-bands, spatially associated with E-W dextral faults. These structures are contemporaneous and affect the previously deformed Carboniferous units. The Ponta Ruiva Sector constrains the age of deformation because the E-W dextral shears affect the Late Carboniferous (late Moscovian) units, but not the overlying Triassic series. The new exposed data shows that the NNE-SSW and the E-W faults are dynamically associated and results from the same deformation event. The NNE-SSW sinistral faults could be considered as second order dominoes structures related with first order E-W dextral shears, related with Laurasia-Gondwana collision during Late Carboniferous-Permian Times.

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The thesis examines the technical aspects of unglazed molded ceramics from Mértola, in the context of Islamic archaeology of the Iberian Peninsula (Almohad period, end of 12th and the beginning of 13th century). Ceramics of the time period under discussion (12th – 13th century) are understudied, including in what concern to shaping and firing of ceramic vessels, the origin of raw materials used in ceramics and glazes, and decoration methods such as slip painting and/or colored glazes. Moreover, the use of archaeometry tools is rare. Along with providing a general picture of molded ceramic production in Mértola, this work provides a new dimension to the discipline of Islamic ceramic studies by the analytical tool used and demonstrating the importance of archaeological ceramics of the western peripheries to the understanding the production of ceramics and the transmission of knowledge and cultural traditions within the Islamic caliphate. The chemical and mineralogical characterization of 12th/13th century Almohad unglazed molded ware from Mértola was accomplished through multi – analytical approach combining SEM, Powder/uXRD and LA-ICP-MS methods. In this paper unglazed and glazed samples were analyzed but the attention was given to unglazed specimens, while the glazed samples were used for the comparison with the previous group in order to determine possible similarities or dissimilarities, thus providing enough data to discuss about technical aspects and potential provenance; Resumo: A tese debruça-se sobre os aspetos técnicos de cerâmica de molde não-vidrada de Mértola, no contexto da arqueologia islâmica da Península Ibérica (período Almóada, final de XII e início do século XIII). A cerâmica do período em discussão (séculos XII-XIII) é pouco estudada inclusive no que concerne ao fabrico e à cozedura, à de fonte de matérias-primas, na pasta ou nos esmaltes e aos métodos de decoração, como pintura, presença de engobes ou esmaltes. Além disso, o uso de ferramentas de Arqueometria é raro. Para fornecer uma visão geral da produção de cerâmica moldada em Mértola, este trabalho oferece uma nova dimensão para a disciplina de cerâmica islâmicas pelas ferramentas analíticas utilizadas. Demonstrando a importância da cerâmica arqueológica da periferia ocidental para a compreensão da produção cerâmica e a transmissão de conhecimentos e tradições culturais no califado islâmico. A caracterização mineralógica e química das cerâmicas de molde e não-vidrada, Almóada, dos séculos XII-XIII de Mértola foi realizada através de uma abordagem multi-analítica que combina métodos de SEM-EDS, uXRD e LA-ICP-MS. Neste trabalho, as cerâmicas vidradas e não-vidradas foram analisadas conjuntamente, dando mais atenção aos espécimes não vidrados. As amostras de cerâmicas vidradas foram utilizados para a comparação com o grupo anterior, a fim de determinar as possíveis semelhanças ou diferenças, proporcionando, assim, dados suficientes para discutir os aspetos técnicos e o potencial de proveniência das cerâmicas não vidradas