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1. Agricultural landscapes and the Loire River influence the genetic structure of the marbled newt in Western France

Author

Jean-Marc Costanzi, Pascal Mège, Alexandre Boissinot, Francis Isselin-Nondedeu, Sandra Guérin, Olivier Lourdais, Audrey Trochet, Quentin Le Petitcorps, Agathe Legrand, François Varenne, Pierre Grillet, Sophie Morin-Pinaud, and Damien Picard

Subjects
Marbled Newt, Loire River, Discriminant Analysis Of Principal Components (DAPC), DAPC Results, Large Crop Fields, Medicine, Science
Abstract

Abstract Amphibians are particularly sensitive to landscape fragmentation. Potential barriers between breeding sites can negatively influence the dispersal of individuals and increase genetic structure between populations. In this study, we genotyped 10 microsatellites for 334 marbled newts (Triturus marmoratus) at 11 different locations in Western France. Samples were collected in different regions with contrasting agricultural landscapes (low and high proportion of arable land in the north and south, respectively). We found a strong genetic structure between the northern and southern sampling sites. Isolation by distance was recorded after 62 km, but within the northern region, little or no genetic structure was detected over large distances (up to 114 km). Genetic structure at shorter distance (43 km) was found between sites situated in landscapes with larger amounts of arable lands. A significant positive relationship was found between the pairwise genetic distance (Fst) between sites and the amount of arable land together with the distance between sites. Our results suggest that the Loire River might act as a corridor for the marbled newt, while arable land might act as a barrier. Finally, although a large city is located between sampling sites, no effect was detected on population structure.

Published
2018
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2. Agricultural intensification alters marbled newt genetic diversity and gene flow through density and dispersal reduction

Author

Raphaël Leblois, Pierre Grillet, Olivier Lourdais, Alexandre Boissinot, Bertrand Gauffre, Vincent Quiquempois, Sophie Morin, Damien Picard, Cécile Ribout, School of Biological Sciences [Clayton], Monash University [Clayton], Unité de recherche Plantes et Systèmes de Culture Horticoles (PSH), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Réserve Naturelle Régionale du Bocage des Antonins [France], Office français de la biodiversité (OFB), Département de Biologie UFR Sciences - Université d'Angers [France], Université d'Angers (UA), and Centre d’Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS - La Rochelle Université, France, 79360, Villiers-en-Bois, France

Subjects
0106 biological sciences, Gene Flow, Triturus marmoratus, [SDV]Life Sciences [q-bio], Population, Biology, 010603 evolutionary biology, 01 natural sciences, microsatellites, 03 medical and health sciences, demographic inferences, Effective population size, Genetics, Animals, education, dispersal, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, Ecosystem, 030304 developmental biology, 2. Zero hunger, 0303 health sciences, education.field_of_study, Genetic diversity, Ecology, Genetic Variation, landscape genetics, genetic diversity, 15. Life on land, Salamandridae, Habitat destruction, Genetics, Population, Genetic distance, Genetic structure, [SDE]Environmental Sciences, Biological dispersal, Arable land, Microsatellite Repeats
Abstract

International audience; Recent agricultural intensification threatens global biodiversity with amphibians being one of the most impacted groups. Because of their biphasic life cycle, amphibians are particularly vulnerable to habitat loss and fragmentation that often result in small, isolated populations and loss of genetic diversity. Here, we studied how landscape heterogeneity affects genetic diversity, gene flow and demographic parameters in the marbled newt, Triturus marmoratus, over a hedgerow network landscape in Western France. While the northern part of the study area consists of preserved hedged farm-land, the southern part was more profoundly converted for intensive arable crops production after WWII. Based on 67 sampled ponds and 10 microsatellite loci, we characterized regional population genetic structure and evaluated the correlation between landscape variables and (i) local genetic diversity using mixed models and (ii) genetic distance using multiple regression methods and commonality analysis. We identified a single genetic population characterized by a spatially heterogeneous isolation- by- distance pattern. Pond density in the surrounding landscape positively affected local genetic diversity while arable crop land cover negatively affected gene flow and connectivity. We used demographic inferences to quantitatively assess dif-ferences in effective population density and dispersal between the contrasted land-scapes characterizing the northern and southern parts of the study area. Altogether, results suggest recent land conversion affected T. marmoratus through reduction in both effective population density and dispersal due to habitat loss and reduced connectivity.

Published
2021

3. Global climate modeling of Saturn’s atmosphere. Part IV: Stratospheric equatorial oscillation

Author

Aymeric Spiga, Alexandre Boissinot, Deborah Bardet, Sandrine Guerlet, Simon Cabanes, Ehouarn Millour, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Dipartimento di Fisica [Roma La Sapienza], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), ANR-17-CE31-0007,EMERGIANT,Un modèle commun pour comprendre les atmosphères des géantes gazeuses(2017), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Department of Physics [Roma La Sapienza], and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmospheric circulation, Equator, FOS: Physical sciences, Atmospheric sciences, 01 natural sciences, Troposphere, Saturn, 0103 physical sciences, 010303 astronomy & astrophysics, Stratosphere, ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Oscillation, Astronomy and Astrophysics, Physics - Atmospheric and Oceanic Physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Atmospheric and Oceanic Physics (physics.ao-ph), Astrophysics::Earth and Planetary Astrophysics, Tropopause, Longitude, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Composite InfraRed Spectrometer (CIRS) on board Cassini revealed an equatorial oscillation of stratospheric temperature, reminiscent of the Earth's Quasi-Biennial Oscillation (QBO), as well as anomalously high temperatures under Saturn's rings. To better understand these predominant features of Saturn's atmospheric circulation in the stratosphere, we have extended towards higher altitudes the DYNAMICO-Saturn global climate model (GCM), already used in a previous publication to study the tropospheric dynamics, jets formation and planetary-scale waves activity. Firstly, we study the higher model top impact on the tropospheric zonal jets and kinetic energy distribution. Raising the model top prevents energy and enstrophy accumulation at tropopause levels. The reference GCM simulation with 1/2$^{\circ}$ latitude/longitude resolution and a raised model top exhibits a QBO-like oscillation produced by resolved planetary-scale waves. However, the period is more irregular and the downward propagation faster than observations. Furthermore, compared to the CIRS observation retrievals, the modeled QBO-like oscillation underestimates by half both the amplitude of temperature anomalies at the equator and the vertical characteristic length of this equatorial oscillation. This QBO-like oscillation is mainly driven by westward-propagating waves; a significant lack of eastward wave-forcing explains a fluctuating eastward phase of the QBO-like oscillation. At 20$^{\circ}$N and 20$^{\circ}$S latitudes, the DYNAMICO-Saturn GCM exhibits several strong seasonal eastward jets, alternatively in the northern and southern hemisphere. These jets are correlated with the rings' shadowing. Using a GCM simulation without rings' shadowing, we show its impact on Saturn's stratospheric dynamics. Both residual-mean circulation and eddy forcing are impacted by rings' shadowing., Comment: 54 pages, 23 figures, revised version submitted to Icarus

Published
2021
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4. Global climate modeling of Saturn's atmosphere. Part II: Multi-annual high-resolution dynamical simulations

Author

Sébastien Lebonnois, Aymeric Spiga, Melody Sylvestre, Mikel Indurain, Yann Meurdesoif, Thomas Dubos, Alexandre Boissinot, Simon Cabanes, Sandrine Guerlet, Thierry Fouchet, Ehouarn Millour, Jérémy Leconte, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), ECLIPSE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Calcul Scientifique (CALCULS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), ANR-17-CE31-0007,EMERGIANT,Un modèle commun pour comprendre les atmosphères des géantes gazeuses(2017), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
010504 meteorology & atmospheric sciences, Baroclinity, Equator, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, 7. Clean energy, symbols.namesake, Saturn, Barotropic fluid, 0103 physical sciences, 010303 astronomy & astrophysics, Stratosphere, Physics::Atmospheric and Oceanic Physics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Jet (fluid), Rossby wave, Astronomy and Astrophysics, Geophysics, Physics - Atmospheric and Oceanic Physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Atmospheric and Oceanic Physics (physics.ao-ph), symbols, Astrophysics::Earth and Planetary Astrophysics, Kelvin wave, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Cassini mission unveiled the intense and diverse activity in Saturn's atmosphere: banded jets, waves, vortices, equatorial oscillations. To set the path towards a better understanding of those phenomena, we performed high-resolution multi-annual numerical simulations of Saturn's atmospheric dynamics. We built a new Global Climate Model [GCM] for Saturn, named the Saturn DYNAMICO GCM, by combining a radiative-seasonal model tailored for Saturn to a hydrodynamical solver based on an icosahedral grid suitable for massively-parallel architectures. The impact of numerical dissipation, and the conservation of angular momentum, are examined in the model before a reference simulation employing the Saturn DYNAMICO GCM with a $1/2^{\circ}$ latitude-longitude resolution is considered for analysis. Mid-latitude banded jets showing similarity with observations are reproduced by our model. Those jets are accelerated and maintained by eddy momentum transfers to the mean flow, with the magnitude of momentum fluxes compliant with the observed values. The eddy activity is not regularly distributed with time, but appears as bursts; both barotropic and baroclinic instabilities could play a role in the eddy activity. The steady-state latitude of occurrence of jets is controlled by poleward migration during the spin-up of our model. At the equator, a weakly-superrotating tropospheric jet and vertically-stacked alternating stratospheric jets are obtained in our GCM simulations. The model produces Yanai (Rossby-gravity), Rossby and Kelvin waves at the equator, as well as extratropical Rossby waves, and large-scale vortices in polar regions. Challenges remain to reproduce Saturn's powerful superrotating jet and hexagon-shaped circumpolar jet in the troposphere, and downward-propagating equatorial oscillation in the stratosphere., Comment: 68 pages, 23 figures, published in Icarus https://doi.org/10.1016/j.icarus.2019.07.011

Published
2020

5. Amphibian diversity in farmlands: Combined influences of breeding-site and landscape attributes in western France

Author

Aurélien Besnard, Olivier Lourdais, Alexandre Boissinot, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), School of Life Sciences [Tempe, USA], Arizona State University [Tempe] (ASU), The Fondation Marcel Bleustein Blanchet (‘Bourse de la Vocation’ grant), The Fondation de France (‘Bourse Déclic Jeune’ grant), The Conseil Régional of Poitou-Charentes (Programme Bocage, Reptiles et Amphibiens), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)

Subjects
0106 biological sciences, Hedgerow networks, Biodiversity, Conservation, 010603 evolutionary biology, 01 natural sciences, Life history theory, Amphibians, Ponds, 2. Zero hunger, Ecology, business.industry, fungi, 04 agricultural and veterinary sciences, Vegetation, 15. Life on land, Habitat, Habitat destruction, Geography, Agriculture, [SDE]Environmental Sciences, 040103 agronomy & agriculture, Spatial ecology, 0401 agriculture, forestry, and fisheries, Animal Science and Zoology, Species richness, business, Agronomy and Crop Science
Abstract

International audience; Agricultural intensification is responsible for major habitat degradation and is a primary cause of biodiversity loss. Amphibians are currently facing a global decline induced by multiple pressures, including notably habitat degradation and land conversion. In western Europe, traditional farming systems involve a dense hedgerow network with a mosaic of pastures, cultivated fields, ponds, and small woods. These heterogeneous landscapes are particularly favorable for biodiversity but their role for amphibian conservation remain understudied.We studied the amphibian community (15 species) of a hedgerow network landscape in western France. We described 79 cattle ponds and tested the influence of ponds characteristics as well as the surrounding landscape composition on species occurrence. Amphibian diversity was positively influenced by breeding site vegetation and also ponds density in the surrounding landscape. We also found positive effects of wood patches and hedgerow linear at a small spatial scale. In turn, crop cover and road linear negatively influenced amphibian richness at large spatial scale. Important variation were detected among species reflecting contrasted life history traits. Our results underline that traditional pastoral landscapes provide a high density of breeding sites and habitats favorable for a diversity of amphibian species.

Published
2019

6. Determinants of mercury contamination in viperine snakes, Natrix maura , in Western Europe

Author

Olivier Lourdais, Pedro Galán, François Brischoux, Alexandre Boissinot, Jérémy Lemaire, Paco Bustamante, Bruno Michaud, Anthony Olivier, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR), Réserve Naturelle Nationale de Chérine, Maison de la Nature et de la Réserve, LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche de la Tour du Valat, Grupo de Investigación en Bioloxía Evolutiva (GIBE) [SPAIN], Universidade de A Coruña, Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs)

Subjects
Male, Environmental Engineering, 010504 meteorology & atmospheric sciences, Fish farming, Natricinae, Zoology, 010501 environmental sciences, 01 natural sciences, Freshwater ecosystem, Sex Factors, Trace metals, Environmental Chemistry, Animals, Body Size, 14. Life underwater, Waste Management and Disposal, Natrix maura, 0105 earth and related environmental sciences, biology, Colubridae, Freshwater ecosystems, Biota, Environmental Exposure, Mercury, biology.organism_classification, Pollution, Diet, Trout, Spain, Bioaccumulation, [SDE]Environmental Sciences, Freshwater fish, Female, France, Water Pollutants, Chemical, Environmental Monitoring
Abstract

International audience; The effects of Hg contamination are presumably widespread across the components of aquatic ecosystems, but investigations have been mainly focused on freshwater fish, because this biota represents a major source of Hg for human populations. Yet, the possible bioaccumulation of Hg on other freshwater meso- and apex-predators (e.g., amphibians, reptiles) has been largely overlooked, especially in Western Europe. In this study, the determinants of Hg concentrations were assessed for the viperine snake (Natrix maura) across 6 populations (>130 individuals sampled in 2016 and 2017) in France and Spain. Specifically, body size, sex, and diet were compared with Hg concentrations measured in ventral scales. Overall, N. maura accumulated Hg in their scales. Sex did not seem to influence Hg concentrations in this species. Significant differences in Hg concentrations were observed between study sites, and these differences were likely to be mediated by site-specific diet. Frog-eating individuals were characterized not only by lower mean values of Hg (0.194 ± 0.018 μg·g−1 versus 0.386 ± 0.032 μg·g−1 for piscivorous individuals), but also by weaker slopes of the body size-Hg relationship as compared to fish-eating snakes, suggesting strong differences in accumulation rates due to food resources. Importantly, the highest slope of the body size-Hg relationship and the highest values of Hg were found in individuals foraging on trout raised by a fish farm, suggesting that fish farming may contribute to Hg contamination in inland freshwater systems. Finally, our results are compared with data on Hg concentrations in other species of aquatic snakes, in order to provide a comparative point for future studies.

Published
2018

7. Influence of temperature, size and confinement on testosterone and corticosterone levels in breeding male spined toads (Bufo spinosus)

Author

François Brischoux, Alexandre Boissinot, Frédéric Angelier, Olivier Lourdais, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, 0301 basic medicine, Male, Range (biology), Explosive breeding, Captivity, Zoology, Toad, Breeding, Stress, 010603 evolutionary biology, 01 natural sciences, 03 medical and health sciences, chemistry.chemical_compound, Endocrinology, Corticosterone, biology.animal, Mating call, Animals, Body Size, Testosterone, Mating, Glucocorticoids, Winter-breeding, Body condition, biology, Phenology, Body Weight, Temperature, Bufonidae, Anurans, 030104 developmental biology, chemistry, [SDE]Environmental Sciences, Androgens, Animal Science and Zoology, Female
Abstract

Winter breeding amphibians opportunistically engage in reproductive behaviour when environmental conditions become favourable. In such explosive breeding systems, males strongly compete for reproductive females. Although most research has been oriented on species in which males use mating calls to attract females, many high-density explosive breeding amphibians do not rely on mating calls. In such systems, larger and stronger males are thought to have significant advantages to access reproductive females. Testosterone (T) is expected to increase with the physical attributes that facilitate access to females, while increased corticosterone levels (CORT) are needed to sustain the energetic requirements associated with mating behaviour. In this study, we investigated how environmental temperature, and body size influence testosterone and corticosterone in males of an explosive winter-breeding species with low investment in mating call, the spined toad (Bufo spinosus). We found that both baseline CORT and T were positively correlated with environmental temperature. Interestingly, despite a remarkable range of variation in CORT and T, there was no evidence that either hormone was correlated with body size. Finally, we found no effect of confinement (13 h of captivity) on circulating CORT and T levels. This suggests that breeding male toads may be relatively insensitive to stress in order to maintain reproductive effort during their short mating period. Future studies should investigate both the influence of the phenology of breeding and the social interactions on these hormonal levels.

Published
2018

8. Author Correction: Agricultural landscapes and the Loire River influence the genetic structure of the marbled newt in Western France

Author

François Varenne, Olivier Lourdais, Jean-Marc Costanzi, Quentin Le Petitcorps, Pierre Grillet, Agathe Legrand, Francis Isselin-Nondedeu, Alexandre Boissinot, Damien Picard, Sandra Guérin, Audrey Trochet, Pascal Mège, and Sophie Morin-Pinaud

Subjects
0301 basic medicine, Multidisciplinary, Ecology, Marbled meat, lcsh:R, lcsh:Medicine, 03 medical and health sciences, 030104 developmental biology, Geography, Genetic structure, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, lcsh:Q, Author Correction, lcsh:Science, Agricultural landscapes
Abstract

Amphibians are particularly sensitive to landscape fragmentation. Potential barriers between breeding sites can negatively influence the dispersal of individuals and increase genetic structure between populations. In this study, we genotyped 10 microsatellites for 334 marbled newts (Triturus marmoratus) at 11 different locations in Western France. Samples were collected in different regions with contrasting agricultural landscapes (low and high proportion of arable land in the north and south, respectively). We found a strong genetic structure between the northern and southern sampling sites. Isolation by distance was recorded after 62 km, but within the northern region, little or no genetic structure was detected over large distances (up to 114 km). Genetic structure at shorter distance (43 km) was found between sites situated in landscapes with larger amounts of arable lands. A significant positive relationship was found between the pairwise genetic distance (F

Published
2018

9. Landscape influences the morphology of male common toads (Bufo bufo)

Author

Xavier Bonnet, François Brischoux, Frédéric Angelier, Olivier Lourdais, Alexandre Boissinot, Héloïse Guillot, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, Agroecosystem, Larva, Ecology, Biodiversity, Toad, 010501 environmental sciences, 15. Life on land, Biology, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Fluctuating asymmetry, Habitat, biology.animal, [SDE]Environmental Sciences, Spatial ecology, Animal Science and Zoology, Bufo, Agronomy and Crop Science, 0105 earth and related environmental sciences
Abstract

International audience; In Europe, the recent agricultural intensification has strongly homogenised the landscape. This loss in habitat diversity and the use of agrochemicals are considered as major causes of the global erosion of biodiversity. Landscape changes may also favour phenotypic variation with divergences between populations even at a small spatial scale. We investigated this notion in the common toad (Bufo bufo), a species that inhabits a wide variety of rural habitats. Specifically, we compared the morphology of male adult toads from three contrasting landscapes: forests, traditional farming landscape and intensive farmlands. Overall, individuals from open landscapes were larger and heavier, had longer hind legs and larger parotoid glands than their forest counterparts; suggesting that open landscapes positively influence body size in this species. However, toads from intensive farmland were less symmetrical, suggesting that these individuals may have experienced environmental stress during larval and/or post-metamorphic development. Overall, our results suggest that landscape-specific traits can influence the morphology of male toads in complex ways. Further studies are required to comprehensively assess the impacts of environmental and anthropogenic pressures on amphibians in agroecosystems.

Published
2016

10. Small woods positively influence the occurrence and abundance of the common frog (Rana temporaria) in a traditional farming landscape

Author

Alexandre Boissinot, Pierre Grillet, Aurélien Besnard, Olivier Lourdais, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UM3)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, Ecology, business.industry, 010604 marine biology & hydrobiology, 15. Life on land, Biology, 010603 evolutionary biology, 01 natural sciences, Habitat, Agriculture, Abundance (ecology), Extensive farming, Western europe, [SDE]Environmental Sciences, Animal Science and Zoology, business, Ecology, Evolution, Behavior and Systematics
Abstract

Traditional farming landscape in western Europe is made of a complex mosaic of pastures, cultures, ponds and hedgerows connected with woods. Previous observations in the common frog species suggest that lowland populations are closely associated to wood cover and our aim was to test the validity of this assumption. We studied common frog occurrence and abundance in western central France (Deux-Sèvres department) close to the southern margin of lowland distribution. Our results pointed out that the proportion of woods surface around sampled areas (1 ha) was a critical determinant of common frog presence and abundance. Extensive farming, which maintains a mosaic of small woods, may provide a robust conservation tool for this species.

Published
2015

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