320 research outputs found

    Similar compositional turnover but distinct insular environmental and geographical drivers of native and exotic ants in two oceans

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    Aim This study aims to quantify the patterns in compositional turnover of native and exotic ants on small islands in two oceans, and to explore whether such patterns are driven by similar environmental, geographical and potentially biotic variables. Location Pacific and Atlantic islands. Time period Present. Major taxa studied Ants. Methods We applied Multi‐Site Generalised Dissimilarity Modelling (MS‐GDM), which relates zeta diversity, the number of species shared by a given number of islands, to differences in environmental, geographical and biotic drivers. The use of zeta diversity enabled us to differentiate the contribution of rare species (shared by few islands) from those of widespread ones (shared by multiple islands) to compositional turnover. For completion, we also related species richness of insular ants per island with the same set of explanatory variables using Generalised Additive Models (GAM). Results Pacific and Atlantic islands have similar patterns of ant species turnover and richness, albeit partly driven by different drivers. Native and exotic species turnover are mostly explained by the same set of variables in the Pacific (annual precipitation and distance to the nearest island), but not in the Atlantic (annual precipitation is a good predictor of native species turnover, but none of the variables considered in our study explained exotic species turnover). No signal of biotic interactions was detected at the insular community level. Main conclusions Successful invasion strategies may depend on a combination of factors specific to the region in question. In the Pacific, milder environments and the absence of natives on certain islands enable exotic ants to select the same types of environment as native ants. In the harsher Atlantic Ocean, however, native ant species are likely to be well adapted to local environmental conditions, making it harder for exotics to become established. Exotic ant species, therefore, potentially rely on other attributes to establish, such as a combination of tolerance to a wide range of environmental conditions and human‐mediated colonization

    Influencia de factores bióticos a escala local y de paisaje en la distribución del muérdago en pinares mediterráneos

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    The study of the spatial patterns of species allows the examination of hypotheses on the most plausible ecological processes and factors determining their distribution. To investigate the determinants of parasite species on Mediterranean forests at regional scales, occurrence data of the European Misletoe (Viscum album) in Catalonia (NE Iberian Peninsula) were extracted from forest inventory data and combined with different types of explanatory variables by means of generalized linear mixed models. The presence of mistletoes in stands of Pinus halepensis seems to be determined by multiple factors (climatic conditions, and characteristics of the host tree and landscape structure) operating at different spatial scales, with the availability of orchards of Olea europaea in the surroundings playing a relevant role. These results suggest that host quality and landscape structure are important mediators of plant-plant and plant-animal interactions and, therefore, management of mistletoe populations should be conducted at both local (i.e. clearing of infected host trees) and landscape scales (e.g. controlling the availability of nutrient-rich food sources that attract bird dispersers). Research and management at landscape-scales are necessary to anticipate the negative consequence of land-use changes in Mediterranean forests.El estudio de los patrones espaciales de las especies permite examinar hipótesis sobre los procesos ecológicos y factores más plausibles que determinan su distribución. Para investigar los determinantes de una especie parásita en bosques mediterráneos a escala regional, se combinaron datos sobre la presencia de muérdago (Viscum album) en Cataluña (NE de la Península Ibérica) extraídos del inventario forestal con diferentes variables explicativas por medio de modelos mixtos generalizados. La presencia de muérdago en masas de Pinus halepensis parece estar determinada por múltiples factores (condiciones climáticas, características del árbol hospedante, y estructura del paisaje) que operan a diferentes escalas espaciales, jugando los cultivos de Olea europaea un papel relevante. Los resultados sugieren que la calidad de los árboles hospedantes y la estructura del paisaje son importantes mediadores de las interacciones planta-planta y planta- animal y, por tanto, la gestión de las poblaciones de muérdago debería llevarse a cabo tanto a nivel local (es decir, cortando árboles hospedantes infectados) como de paisaje (por ejemplo, controlando la disponibilidad de hábitats ricos en nutrientes que atraen a las aves dispersantes). La investigación y gestión a escala de paisaje son necesarias para prevenir las consecuencias negativas de los cambios de uso del suelo en los bosques mediterráneos

    Uncertainty and sensitivity analysis in quantitative pest risk assessments : practical rules for risk assessors

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    Quantitative models have several advantages compared to qualitative methods for pest risk assessments (PRA). Quantitative models do not require the definition of categorical ratings and can be used to compute numerical probabilities of entry and establishment, and to quantify spread and impact. These models are powerful tools, but they include several sources of uncertainty that need to be taken into account by risk assessors and communicated to decision makers. Uncertainty analysis (UA) and sensitivity analysis (SA) are useful for analyzing uncertainty in models used in PRA, and are becoming more popular. However, these techniques should be applied with caution because several factors may influence their results. In this paper, a brief overview of methods of UA and SA are given. As well, a series of practical rules are defined that can be followed by risk assessors to improve the reliability of UA and SA results. These rules are illustrated in a case study based on the infection model of Magarey et al. (2005) where the results of UA and SA are shown to be highly dependent on the assumptions made on the probability distribution of the model inputs

    Macroparasites of allis shad (Alosa alosa) and twaite shad (Alosa fallax) of the Western Iberian Peninsula Rivers : ecological, phylogenetic and zoonotic insights

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    Acknowledgments The authors sincerely thank M.N. Cueto, J.M. Antonio and M.E. Garci of the ECOBIOMAR group at IIM-CSIC for molecular analysis, technical support and quality images of some parasites. M. Bao is supported by a PhD grant from the University of Aberdeen and also by financial support of the contract from the EU Project PARASITE (grant number 312068). A. Roura is supported by Fundación Barrié de la Maza postdoctoral fellowship and a Securing Food, Water and the Environment Research Focus Area grant (La Trobe University). This study was partially supported by a PhD grant from the Portuguese Foundation for Science and Technology (FCT) (SFRH/BD/4892/2008) and partially supported by the European Regional Development Fund (ERDF) through the COMPETE—Operational Competitiveness Programme and national funds through FCT—Foundation for Science and Technology, under the project PEst-C/MAR/LA0015/2013. The authors thank the staff of the Station of Hydrobiology of the USC Encoro do Con^ due their participation in the surveys, with special mention to J. Sánchez for separating digenean fauna existing in the stomachs of A. fallax. This work has been partially supported by the project 10PXIB2111059PR of the Xunta de Galicia and the project MIGRANET of the Interreg IV B SUDOE (South-West Europe) Territorial Cooperation Programme (SOE2/P2/E288). D.J. Nachón is supported by a PhD grant from the Xunta de Galicia (PRE/2011/198)Peer reviewedPostprin

    Assessing the distribution of the Argentine ant using physiological data

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    To address the lack of physiological approaches in current models assessing the potential distribution of the Argentine ant, we used data on brood development from distinct sources to evaluate a series of degreeday models for Catalonia (NE Iberian Peninsula), and data on the brood survival and oviposition rates to develop a worker production model. The degree-day model generated using data from Newell and Barber (1913) and Benois (1973) indicated that the number of degree-days required for the complete development from egg to adult worker was 445.4 degree-days above a threshold of 15.9°C, while the model calibratedusing data from Abril et al. (2008, in press) suggested 599.5 degree-days above 18.4°C. Comparisons between the degree-day model predictions and the currently known distribution of the Argentine ant suggested that the one generated using data from Newell and Barber (1913) and Benois (1973) overestimated the presence of the species, while the one calibrated using data from Abril et al. (2008; in press) underestimated it. On the other hand, the predicted daily net production of Argentine ant workers generated by the worker production model predicted more accurately the distribution of the Argentine ant than the degree-day models. Our results show the utility of incorporating physiological data in models to assess the distribution limits of the Argentine ant, which up to date have taken little account of the physiological needs of the species in terms of its establishment and dispersion in its introduced ranges.Centre of Excellence for Invasion Biolog

    Complicaciones vasculares tras cateterismo cardíaco

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    Objetivos: Establecer la incidencia de complicaciones vasculares tras un cateterismo cardíaco y determinar los factores que influyen en la aparición de los mismos. Material y métodos: Revisión retrospectiva de los 3723 cateterismos cardíacos realizados en nuestro hospital durante un período de 50 meses. Se recogieron 32 traumatismos vasculares, distribuidos entre pseudoaneurismas, hematomas o hemorragias incoercibles, fístulas arteriovenosas e isquemias agudas por trombosis arterial. Se realizó un analisis estadístico mediante tablas de contingencia (método de Jicuadrado, con corrección de Yates). Resultados: La incidencia anual de traumatismos vasculares se encuentra alrededor del 1 %. La incidencia de traumatismos tras un cateterismo terapéutico es ligeramente superior a la incidencia tras un cateterismo diagnóstico, sin presentar diferencias significativas. La edad media del grupo de pacientes con traumatismo vascular (grupo estudio) es de 64'2 ± 1 '9 años, ligeramente superior a la edad media del grupo sin traumatismo vascular (grupo control) (61 '1 - 0'2 años). En ambos grupos predominaban los varones, pero en el grupo estudio dicho predominio es sensi blemente inferior (p 0'012) . En el grupo estudio la incidencia de pacientes obesos es superior con respecto al grupo control (p 0'024). El abordaje por vía humeral (p 0'03), el diametro de cateter mayor al 8F (p 0'001) Y la anticoagulación tras el cateterismo (p<0'001) son factores favorecedores par la aparición de un traumatismo vascular tras un cateterismo cardíaco

    Capacity of countries to reduce biological invasions

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    The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-economic and environmental factors, which exhibit high variation among countries. Yet, a global analysis of how these factors vary across countries is currently lacking. Here, we investigate how five broad, country-specific socio-economic and environmental indices (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain country-level (1) established alien species (EAS) richness of eight taxonomic groups, and (2) proactive or reactive capacity to prevent and manage biological invasions and their impacts. These indices underpin many aspects of the invasion process, including the introduction, establishment, spread and management of alien species. They are also general enough to enable a global comparison across countries, and are therefore essential for defining future scenarios for biological invasions. Models including Trade, Governance, Lifestyle and Education, or a combination of these, best explained EAS richness across taxonomic groups and national proactive or reactive capacity. Historical (1996 or averaged over 1996–2015) levels of Governance and Trade better explained both EAS richness and the capacity of countries to manage invasions than more recent (2015) levels, revealing a historical legacy with important implications for the future of biological invasions. Using Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions, we identified four main clusters of countries in 2015. Most countries had an increase in Trade over the past 25 years, but trajectories were more geographically heterogeneous for Governance. Declines in levels of Governance are concerning as they may be responsible for larger levels of invasions in the future. By identifying the factors influencing EAS richness and the regions most susceptible to changes in these factors, our results provide novel insights to integrate biological invasions into scenarios of biodiversity change to better inform decision-making for policy and the management of biological invasions

    A Framework for Global Twenty-First Century Scenarios and Models of Biological Invasions

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    Biological invasions have emerged as an eminent feature of global change, with substantial impacts on the environment and human livelihoods. Current research demonstrates that the numbers and impacts of alien species are rising unabatedly. At the same time, we lack a thorough understanding of potential future trajectories for the decades to come. With the recent establishment of comprehensive global databases, it is, for the first time, feasible to develop and quantify future scenarios of biological invasions. Therefore, we propose a conceptual framework for how to develop alien species scenarios for the twenty-first century and how to identify relevant steps and challenges along the way. The concept will be important to inform research, policy, stakeholders, and the general public. Furthermore, we call for the scientific community to join forces and to operationalize the framework for scenarios and models of biological invasions to develop an important baseline for understanding and managing future biological invasions

    Capacity of countries to reduce biological invasions

    Get PDF
    The extent and impacts of biological invasions on biodiversity are largely shaped by an array of socio-economic and environmental factors, which exhibit high variation among countries. Yet, a global analysis of how these factors vary across countries is currently lacking. Here, we investigate how five broad, country-specific socio-economic and environmental indices (Governance, Trade, Environmental Performance, Lifestyle and Education, Innovation) explain country-level (1) established alien species (EAS) richness of eight taxonomic groups, and (2) proactive or reactive capacity to prevent and manage biological invasions and their impacts. These indices underpin many aspects of the invasion process, including the introduction, establishment, spread and management of alien species. They are also general enough to enable a global comparison across countries, and are therefore essential for defining future scenarios for biological invasions. Models including Trade, Governance, Lifestyle and Education, or a combination of these, best explained EAS richness across taxonomic groups and national proactive or reactive capacity. Historical (1996 or averaged over 1996–2015) levels of Governance and Trade better explained both EAS richness and the capacity of countries to manage invasions than more recent (2015) levels, revealing a historical legacy with important implications for the future of biological invasions. Using Governance and Trade to define a two-dimensional socio-economic space in which the position of a country captures its capacity to address issues of biological invasions, we identified four main clusters of countries in 2015. Most countries had an increase in Trade over the past 25 years, but trajectories were more geographically heterogeneous for Governance. Declines in levels of Governance are concerning as they may be responsible for larger levels of invasions in the future. By identifying the factors influencing EAS richness and the regions most susceptible to changes in these factors, our results provide novel insights to integrate biological invasions into scenarios of biodiversity change to better inform decision-making for policy and the management of biological invasions
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