Evolution of Ossoue Glacier (French Pyrenees) since the end of the Little Ice Age

International audienceLittle is known about the fluctuations of the Pyre-nean glaciers. In this study, we reconstructed the evolution of Ossoue Glacier (42 • 46 N, 0.45 km 2), which is located in the central Pyrenees, from the Little Ice Age (LIA) onwards. To do so, length, area, thickness, and mass changes in the glacier were generated from historical data sets, topo-graphical surveys, glaciological measurements (2001–2013), a ground penetrating radar (GPR) survey (2006), and stereo-scopic satellite images (2013). The glacier has receded considerably since the end of the LIA, losing 40 % of its length and 60 % of its area

A Holistic Landscape Description Reveals That Landscape Configuration Changes More over Time than Composition: Implications for Landscape Ecology Studies

International audienceBackground: Space-for-time substitution—that is, the assumption that spatial variations of a system can explain and predict the effect of temporal variations—is widely used in ecology. However, it is questionable whether it can validly be used to explain changes in biodiversity over time in response to land-cover changes.Hypothesis: ere, we hypothesize that different temporal vs spatial trajectories of landscape composition and configuration may limit space-for-time substitution in landscape ecology. Land-cover conversion changes not just the surface areas given over to particular types of land cover, but also affects isolation, patch size and heterogeneity. This means that a small change in land cover over time may have only minor repercussions on landscape composition but potentially major consequences for landscape configuration.Methods: sing land-cover maps of the Paris region for 1982 and 2003, we made a holistic description of the landscape disentangling landscape composition from configuration. After controlling for spatial variations, we analyzed and compared the amplitudes of changes in landscape composition and configuration over time.Results: For comparable spatial variations, landscape configuration varied more than twice as much as composition over time. Temporal changes in composition and configuration were not always spatially matched.Significance: The fact that landscape composition and configuration do not vary equally in space and time calls into question the use of space-for-time substitution in landscape ecology studies. The instability of landscapes over time appears to be attributable to configurational changes in the main. This may go some way to explaining why the landscape variables that account for changes over time in biodiversity are not the same ones that account for the spatial distribution of biodiversity

Evaluating the spatial uncertainty of future land abandonment in a mountain valley (Vicdessos, Pyrenees-France) : insights form model parameterization and experiments

International audienceEuropean mountains are particularly sensitive to climatic disruptions and land use changes. The latter leads to high rates of natural reforestation over the last 50 years. Faced with the challenge of predicting possible impacts on ecosystem services, LUCC models offer new opportunities for land managers to adapt or mitigate their strategies. Assessing the spatial uncertainty of future LUCC is crucial for the defintion of sustainable land use strategies. However, the sources of uncertainty may differ, including the input parameters, the model itself, and the wide range of possible futures. The aim of this paper is to propose a method to assess the probability of occurrence of future LUCC that combines the inherent uncertainty of model parameterization and the ensemble uncertainty of the future based scenarios. For this purpose, we used the Land Change Modeler tool to simulate future LUCC on a study site located in the Pyrenees Mountains (France) and 2 scenarios illustratins 2 land use strategies. The model was parameterized with the same driving factors used for its calibration. The defintion of static vs. dynamic and quantitative vs. qualitative (discretized) driving factors, and their combination resulted in 4 parameterizations. The combination of model outcomes produced maps of spatial uncertainty of future LUCC. This work involves literature to future-based LUCC studies. It goes beyond the uncertainty of simulation models by integrating the unceertainty of the future to provide maps to help decision makers and land managers

Monitoring and modelling landscape dynamics

International audienceChanges in land cover and land use are among the most pervasive and important sources of recent alterations of the Earth's land surface.This special issue also presents new directions in modelling landscape dynamics. Agent-based models have primarily been used to simulate local land use and land cover changes processes with a focus on decision making (Le 2008; Matthews et al. 2007; Parker et al. 2003; Bousquet and Le Page 2001)

High Expression of Testes-Specific Protease 50 Is Associated with Poor Prognosis in Colorectal Carcinoma

Testes-specific protease 50 (TSP50) is normally expressed in testes and abnormally expressed in breast cancer, but whether TSP50 is expressed in colorectal carcinoma (CRC) and its clinical significance is unclear. We aimed to detect TSP50 expression in CRC, correlate it with clinicopathological factors, and assess its potential diagnostic and prognostic value. = 0.009).Our data demonstrate that TSP50 is a potential effective indicator of poor survival for CRC patients, especially for those with early-stage tumors

Eigenvector-based approach to neutrino mixing

We propose a model-independent analysis of the neutrino mass matrix through an expansion in terms of the eigenvectors defining the lepton mixing matrix, which we show can be parametrized as small perturbations of the tribimaximal mixing eigenvectors. This approach proves to be powerful and convenient for some aspects of lepton mixing, in particular when studying the sensitivity of the mass matrix elements to departures from their tribimaximal form. In terms of the eigenvector decomposition, the neutrino mass matrix can be understood as originating from a tribimaximal dominant structure with small departures determined by data. By implementing this approach to cases when the neutrino masses originate from different mechanisms, we show that the experimentally observed structure arises very naturally. We thus claim that the observed deviations from the tribimaximal mixing pattern might be interpreted as a possible hint of a ``hybrid'' nature of the neutrino mass matrix

Action for our planet

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Un atlas de l'occupation du sol pour représenter 200 ans de changements de végétation au sein de la vallée de Bassiès: Résultats d'une nouvelle méthode de spatialisation

International audienceSince the 1950s, the Pyrenean Mountains have undergone abandonment of pasture lands and significant decrease in grazing pressure, leading to a dramatic decline of open lands and their related biodiversity. These findings are mainly based on two types of datasets that remain difficult to combine. On the one hand, they rely on spatially-explicit datasets spanning a few decades, derived from remote sensing (aerial photographs or satellite images). On the other hand, palaeoecological data help to address conservation issues by providing long-term records of land-use and vegetation changes and their possible impacts on biodiversity. However, the spatially explicit, small-scale and long-term reconstruction of land-cover changes, combining both types of data, remains very challenging. The Bassiès valley (OHM Pyrénées - haut Vicdessos) is representative of the Pyrenean mountains abandonment scenario. This poster focuses on the land-cover history of this mountainous area, its local variability and spatial patterns over the last 200 years, based on the sedimentary records of pollen from eight lakes and bogs. Changes in percentage cover of plant taxa at 10-20 year intervals within a 1 km radius around each site were quantified by the landscape reconstruction algorithm (LRA). A new probabilistic and statistic method was then applied to the LRA estimates, producing fine-scale maps (20m pixels) for eight land-cover types. These maps will then be used together with a modern floristic dataset to study the legacies of land-cover composition and configuration changes on floristic diversity. Such results will be further compared to pastoral archives to better understand the human impact on land-cover, floristic and landscape diversities in the valley over the last two centuries.Depuis les années 1950, la déprise pastorale dans les Pyrénées a entraîné un déclin des milieux ouverts et de leur biodiversité. Ces résultats sont principalement basés sur deux types de données. D'une part, ils s'appuient sur des données spatialement explicites couvrant quelques décennies, issus de la télédétection. D'autre part, les données paléoécologiques permettent d'aborder les questions de conservation en fournissant des registres à long terme des changements de végétation et de leurs impacts sur la biodiversité. Cependant il reste très difficile de reconstruire de manière spatialement explicite, à petite échelle et à long terme les changements d’occupation du sol, en combinant les deux types de données. La vallée de Bassiès (OHM Pyrénées - haut Vicdessos) est représentative de l’abandon des estives pyrénéennes. Ce poster aborde l'histoire de l’occupation du sol de cette vallée, de la variabilité locale de sa composition et de sa configuration spatiale au cours des 200 dernières années, en se basant sur les données polliniques de huit lacs et tourbières. L’algorithme de reconstruction des paysages (LRA) a été utilisé pour quantifier les proportions des taxons végétaux à des intervalles de 10 à 20 ans dans un rayon de 1 km autour de chaque site. Une nouvelle méthode probabiliste et statistique a ensuite été appliquée à ces estimations LRA, produisant des cartes à résolution fine (pixels de 20 m) pour huit classes d’occupation du sol. Ces cartes seront ensuite combinées à des données floristiques modernes pour étudier l'héritage des changements d’occupation du sol sur la diversité floristique. Ces résultats seront ensuite comparés aux archives pastorales afin de mieux comprendre l'impact humain sur les diversités paysagère et floristique de la vallée au cours des deux derniers siècles