Marin, Brigitte y Virlouvet, Catherine (eds.), "Entrepôts et trafics annonaires en Méditerranée: antiquité-temps modernes", Roma, École française de Rome, 2016, 406 págs., ISBN: 978-2-7283-1246-7

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Genoese galley contractors and shipping connections in a polycentric empire (sixteenth and seventeenth centuries)

Este artículo analiza la función que la escuadra de los asentistas de galeras genoveses desempeñó en la articulación de varios componentes territoria­les del imperio hispánico entre la segunda mitad del siglo XVI y la primera mitad del siglo XVII. Mientras los estudios sobre la flota mediterránea de la Monarquía se han focalizado generalmente en el ejercicio de la guerra naval, este artículo muestra que, más allá de esta actividad, la escuadra de los genoveses fue clave para el transporte de soldados, metales preciosos, élites de gobierno e información entre la Península Ibérica y el norte de Ita­lia. Este papel fue particularmente relevante durante la guerra de los Ochenta Años (1568-1648), cuando la situación en el Atlántico obligó a la Corona a utilizar el Mediterráneo como plataforma logística para la movi­lización de recursos hacia el norte de Europa. A través del análisis de la aportación de la escuadra hispano-genovesa a esta tarea de articulación naval, este trabajo pretende contribuir a un mayor entendimiento de las ins­tituciones de tipo transnacional que fomentaban la conexión y la circula­ción entre los diferentes componentes de un imperio policéntrico

Instituciones navales y finanzas internacionales en el Mediterráneo de la época moderna. Los asentistas de galeras genoveses al servicio de la Monarquía Hispánica (1500-1650)

Mención Internacional en el título de doctorHasta la fecha los estudios que han analizado la relación entre instituciones navales y expansión económica en la época del mercantilismo, se han centrado en el desarrollo de las flotas nacionales o de las grandes compañías mercantiles. Esta investigación analiza el modelo atípico de la escuadra de los asentistas de galeras genoveses que se pusieron al servicio de la Monarquía Hispánica entre principios del siglo XVI y mitad del siglo XVII. La tesis principal de este trabajo es que los emprendedores navales genoveses no solamente destacaron por desarrollar empresas que conformaron una de las escuadras de galeras más importantes del Mediterráneo, sino que además y sobre todo, sus servicios dieron lugar a externalidades positivas para el sector de las finanzas. Así, esta investigación propone una reevaluación del liderazgo genovés en las finanzas internacionales, argumentando que, a partir de la década de 1570, el uso de las galeras de los asentistas fue la institución clave que les permitió controlar los flujos de metales preciosos, y a partir de ahí, los mercados crediticios de Europa. El trabajo se estructura en cuatro grandes secciones. Primero se centra en la reconstrucción del sistema naval genovés: presenta la escuadra, los asientos y los asentistas de galeras. A continuación, analiza la organización, la gestión y la financiación de las empresas navales genovesas. Después de que se exploran los incentivos que llevaron la Monarquía Hispánica y los genoveses a desarrollar esta institución naval transnacional. La última sección explora los fundamentos navales del capitalismo genovés. Esta investigación se basa en documentación pública, que procede sobre todo de los innumerables fondos del Archivo General de Simancas. También utiliza correspondencia y libros contables privados que pertenecían tanto a emprendedores navales de Génova, como a grandes banqueros genoveses implicados en los asientos de dinero con la Corona de Castilla. Por último, se ha trabajado sobre más documentación que procede fundamentalmente de Madrid, Medina del Campo, Génova, Bolonia, o Venecia.Alors que les travaux historiques qui ont analysé la relation entre les institutions navales et le développement économique durant la période du mercantilisme, se sont principalement intéressés pour l’essor des flottes nationales, ou des grandes compagnies marchandes, cette étude analyse le modèle atypique de l’escadre des asentistas de galères génois qui se mirent au service de la monarchie hispanique au cours des XVIe et XVIIe siècles. La thèse principale de cette étude est que les entrepreneurs navals génois non seulement se montrèrent capables de développer des entreprises qui permirent la formation de l’une des escadres de galères plus importantes de la Méditerranée, sinon qu’en outre, leurs services produisirent des externalités positives sur les finances génoises. En ce sens, ce travail propose une réinterprétation du « siècle des Génois», en soutenant que, tout du moins à partir des années 1570, l’utilisation des galères des asentistas fut une institution déterminante qui leur permirent de contrôler les flux de métaux précieux, et comme conséquence, les marchés de crédit européens. Ce travail reconstruit tout d’abord le système naval génois, en présentant l’escadre, les asientos et les asentistas de galères génois. Ensuite, sont étudiées l’organisation, la gestion et le financement des entreprises navales génoises. La troisième partie explore les motifs qui conduisirent les principales parties impliquées, à développer cette institution transnationale hispano-génoise. La dernière section analyse en profondeur les fondements navals du capitalisme génois. L’enquête s’est basée sur de la documentation publique, qui provient surtout des immenses fonds de l’Archivo General de Simancas. Ont également été utilisés des livres de compte et de la correspondance qui appartenaient aussi bien à des entrepreneurs navals, qu’à de grands banquiers génois qui étaient impliqués dans les asientos d’argent avec la Couronne de Castille. Enfin, de la documentation provenant de Madrid, Medina del Campo, Gênes, Bologne ou Venise a aussi été mobilisée.Programa Oficial de Doctorado en Historia EconómicaPresidente: Carmen Sanz Ayán; Secretario: Manuel Herrero Sánchez.; Vocal: Regina Graf

Beyond variance: Simple random distributions are not a good proxy for intraspecific variability in systems with environmental structure

International audienceThe role of intraspecific variability (IV) in shaping community dynamics and species coexistence has been intensively discussed over the past decade and modelling studies have played an important role in that respect. However, these studies often implicitly assume that IV can be represented by independent random draws around species-specific mean parameters. This major assumption has largely remained undiscussed, although a great part of observed IV is structured in space or time, in particular when environmental dimensions that influence individual performance are imperfectly characterised or unobserved in the field. To test the impact of this strong assumption on the outcome of community dynamics models, we designed a simulation experiment where we varied the level of knowledge of the environment in virtual communities, resulting in different relative importance of explained vs unexplained spatial individual variation in performance. We used a community dynamics simulator to generate communities where the unexplained individual variation is, or is not, added as an unstructured random noise. Communities simulated with unstructured IV never reached the community diversity and composition of those where all the variation was explained and structured (perfect knowledge model). This highlights that incorporating unstructured IV (i.e. a random noise) to account for unexplained (but structured) variation can lead to incorrect simulations of community dynamics. In addition, the effects of unstructured IV on community diversity and composition depended on the relative importance of structured vs unstructured IV, i.e. on the level of knowledge of the environment, which may partly explain the contrasting results of previous studies on the effect of IV on species coexistence. In particular, the effect of unstructured IV on community diversity was positive when the proportion of structured IV vs unstructured IV in the model was low, but negative when this proportion was high. This is because unstructured random noise can either limit the competitive exclusion of inferior competitors in low dimensions or destabilise tight niche partitioning in high dimension. Our study suggests that it is crucial to account for the sources and structure of observed IV in real communities to better understand its effect on community assembly and properly include it in community dynamics models

Rethinking the nature of intraspecific variability and its consequences on species coexistence

International audienceIntraspecific variability (IV) has been proposed to explain species coexistence in diverse communities. Assuming, sometimes implicitly, that conspecific individuals can perform differently in the same environment and that IV increases niche overlap, previous studies have found contrasting results regarding the effect of IV on species coexistence. We aim at showing that the large IV observed in data does not mean that conspecific individuals are necessarily different in their response to the environment and that the role of high-dimensional environmental variation in determining IV has largely remained unexplored in forest plant communities. We first used a simulation experiment where an individual attribute is derived from a high-dimensional model, representing “perfect knowledge” of individual response to the environment, to illustrate how large observed IV can result from “imperfect knowledge” of the environment. Second, using growth data from clonal Eucalyptus plantations in Brazil, we estimated a major contribution of the environment in determining individual growth. Third, using tree growth data from long-term tropical forest inventories in French Guiana, Panama and India, we showed that tree growth in tropical forests is structured spatially and that despite a large observed IV at the population level, conspecific individuals perform more similarly locally than compared with heterospecific individuals. As the number of environmental dimensions that are well quantified at fine scale is generally lower than the actual number of dimensions influencing individual attributes, a great part of observed IV might be represented as random variation across individuals when in fact it is environmentally driven. This mis-representation has important consequences for inference about community dynamics. We emphasize that observed IV does not necessarily impact species coexistence per se but can reveal species response to high-dimensional environment, which is consistent with niche theory and the observation of the many differences between species in nature

Dry-season decline in tree sapflux is correlated with leaf turgor loss point in a tropical rainforest

1. Water availability is a key determinant of forest ecosystem function and tree species distributions. While droughts are increasing in frequency in many ecosystems, including in the tropics, plant responses to water supply vary with species and drought intensity and are therefore difficult to model. Based on physiological first principles, we hypothesized that trees with a lower turgor loss point (pi(tlp)), that is, a more negative leaf water potential at wilting, would maintain water transport for longer into a dry season.2. We measured sapflux density of 22 mature trees of 10 species during a dry season in an Amazonian rainforest, quantified sapflux decline as soil water content decreased and tested its relationship to tree pi(tlp), size and leaf predawn and midday water potentials measured after the onset of the dry season.3. The measured trees varied strongly in the response of water use to the seasonal drought, with sapflux at the end of the dry season ranging from 37 to 117% (on average 83 +/- 5 %) of that at the beginning of the dry season. The decline of water transport as soil dried was correlated with tree pi(tlp) (Spearman's rho >= 0.63), but not with tree size or predawn and midday water potentials. Thus, trees with more drought-tolerant leaves better maintained water transport during the seasonal drought.4. Our study provides an explicit correlation between a trait, measurable at the leaf level, and whole-plant performance under drying conditions. Physiological traits such as pi(tlp) can be used to assess and model higher scale processes in response to drying conditions

Variation of daily sapflux density of 22 trees during a dry season within an Amazonian rainforest

This data file contains the climate data (daily rain in mm, daily potential evapotranspiration - PET - in mm, and relative soil water content - RSWC) and tree sapflux density data (daily sapflux density, Ds, in kg dm-2 day-1) used in Maréchaux et al. All methods, units and tree codes are explicitely described and provided in the corresponding paper