Northwestern France Research Articles

Spatial coexistence and temporal logout between mainland and marine hazards in Upper Normandy (NW France)

This paper focuses on the spatial coexistence between different hazards (strong west winds, beach sedimentary crisis and flash floods) in outlets of small catchments in a sedimentary basin. This study was carried out in the department of Upper Normandy located in north-western France. To anticipate possible future hazards and damages without depending on meteorological triggers (neither intense rainfall nor synoptic conditions), we combine previous knowledge accumulated on local phenomena to highlight the pre-conditioning factors and identify those areas characterised by the highest susceptibility to risk due to the accumulation of numerous hazards. This approach enables both space and time distribution patterns of natural hazards to be revealed. In space, the risk susceptibility strongly depends on morphology. Populations located at the outlet of large wet valleys, at the final outlets of small basins at a short distance from the plateaus and on the coastal fringe appear to be the most endangered. Even if hazards never occur at the same time, these areas can be affected by different hazards during one year (summer flash floods, floods, winter storm surges). This study identifies 14 sensitive areas along hollow shapes of the study area. Finally, our methodological investigations question the creation of a warning system combining mainland and marine hazards in these 14 outlets.

Neology, Competing Authenticities, and the Lexicography of Regional Languages: The Case of Breton

Lexicographic practices when dealing with minoritized regional languages demonstrably differ in certain key respects from such practices with “big” languages like English or French. Prominent among such differences is the treatment of onomasiological gaps, common in small languages of limited currency, including the handling of neologisms and deliberate coinages. Here we propose a case study of Breton, the regional Celtic language of northwestern France, whose sociolinguistic history has divided intellectuals into two camps with competing visions of authenticity: a traditionalist camp focused on the dialectal speech of older, rural native speakers who have long filled lexical gaps by resorting to borrowing from French; and a modernist camp of younger, urban, well educated “Neo-Breton” speakers, whose standardized Breton eschews French lexical influence, looking rather to the Celtic roots of Breton, and even the closely related language Welsh, to fill lexical gaps. In this case study we examine a selection of quasi-technical terms in a corpus of twentieth- and twenty-first-century bilingual Breton lexicography. The study examines the issue of terminological variation attested for such words, their lexicological profile, and the extent to which their lexicographic handling reflects a position with respect to competing notions of authenticity.

Habitat et économie au Néolithique final : l’exemple du site de Raillencourt-Sainte-Olle (Nord) entre activités domestiques et productions artisanales

The site of Raillencourt-Sainte-Olle, ‘ Le Grand Camp’ (Nord) is located on a plateau about 30 m above the Scheldt valley, northwest of the city of Cambrai. Rescue archaeology was undertaken in 1999 and 2000 on a total surface of 1.6 hectares : 14 pits were discovered but they revealed no building plan. Five of these pits yielded the majority of the artefacts. Characteristics of the different categories of artefacts, in particular ceramics, associated with three radiocarbon dates, indicate that the settlement dates from the end of the Neolithic period, at the beginning of the second half of the 3rd millennium, corresponding more or less to the final stages of the Deûle-Escaut culture. The original composition and abundance of the artefacts were incentives for undertaking the thorough study presented in this paper. The presence of numerous loom weights (128, of which 72 are complete) is the first characteristic of this site. This kind of artefact is well known on contemporary or more recent sites, but the number found here makes this set unique for north-western France. Technological analysis undertaken on these loom weights shows that their making did not involve a high degree of technical skill, which seems to be the norm for such items. Their interest lies exclusively in their use. These weights indicate that crafting activities centred on weaving took place in the vicinity of the pits in which they were found. A unique spindle whorl found here can be linked to spinning, the previous step in the textile creation process. The other characteristic of this site lies in the composition of the sandstone assemblage, with a high proportion of hammerstones and anvils and also of raw blocks and flakes, probably linked to the extraction of the material and on-site cutting of the blocks. One of the new aspects of this assemblage is the organised production of flakes meant to be transformed into tools with a blunted fracture platform, whose function is still undefined today. The low proportion of tools for grinding and the absence of polishers are another major difference compared with assemblages from the Deûle valley. In the flint industry, we can emphasize the important proportion of microdenticulates (more than half of the tools). Functional analysis showed a use on rigid tender plants, similar to what is known for this chronological horizon. The characteristics of the archaeological artefacts assemblage lead to an interpretation of the Raillencourt site as an area dedicated to artisanal or craft activities such as weaving, the production of sandstone artefacts, and plant processing. Two theories are discussed here : we are either in the middle of a settlement site where all traces of buildings have disappeared, or this is a dedicated area in connection with a settlement close by, but spatially distinct. Comparisons are proposed with existing data on a local scale where we can find sites with well-dated buildings that are contemporary but where few artefacts are found, and on a broader scale in northern France, in particular in the Deûle valley, and in Belgium, where similar situations occur. They confirm the originality of the artefact assemblage of Raillencourt-Sainte-Olle and the hypothesis of a spatial dissociation of living areas and artisanal areas seems to prevail. In this perspective, the site of Raillencourt-Sainte-Olle could point to an important transformation in the spatial organisation of groups from the end of the Neolithic period, implying greater specialization of areas within a defined territory.

Learning from 8 years of regional cyanobacteria observation in Brittany in view of sanitary survey improvement

Cyanobacteria and cyanotoxins have been more and more studied during the last decades with regard to environment and health issues. More recently the consequences of climate change reinforced the need for research in view of a better management of cyanobacteria blooms. In this context the exploitation of the water quality survey of 26 recreational lakes in Brittany (north western France) between 2004 and 2011 is reported in this paper in order to encompass spatial and interannual patterns of cyanobacteria development at a regional scale. Starting from weekly data principally acquired during summertime, the links between cyanobacteria cell densities, toxin occurrences and interannual meteorological factors can give insights on the potential evolution of cyanobacterial crisis in the future. This study is part of a project aiming at a better understanding of potentially toxic cyanobacteria crisis occurrences in recreational waters, in order to improve predictive monitoring routines.

Schmallenberg Virus Infection in Dogs, France, 2012

To the Editor: In 2011, Schmallenberg virus (SBV) emerged in Europe (1); the virus spread into France in January 2012 (2). During January–March 2012, a total of >1,000 cases were reported in France, mainly in stillborn and newborn lambs with congenital malformations. In March 2012, neurologic disorders were detected in five 15-day-old puppies (Belgian shepherd) from a dog breeding kennel in northwestern France (Orne). We report data suggesting that these puppies were infected with SBV. In June 2012, the kennel veterinarian contacted a veterinary school (Unite de Medecine de l’Elevage et du Sport Breeding and Sport Medicine Unit, Maisons-Alfort, France) after neurologic signs of ataxia, exotropia, a head tilt, and stunted growth were observed in a litter of 5 puppies. Four of the puppies had died at 5–6 weeks of age. The veterinarian collected blood samples from the surviving puppy at 3 months of age, and the puppy was euthanized for necropsy. Severe torticollis was observed during the necropsy, but no other macroscopic signs were detected. The brain, including the cerebellum; a part of the spine; and cerebrospinal fluid (CSF) were collected for further investigation. Specific PCR analyses for canine coronavirus, Neospora caninum, Toxoplasma gondii, and canine minute virus were performed on CSF; all test results were negative. The brain tissue was fixed in formalin and processed for histologic examination. Features of degenerative encephalopathy, including neuronal vacuolation, neuropil vacuolation, and minimal gliosis, were observed. Because some clinical signs were evocative of SBV infection and the puppy was born in an area where the virus was circulating actively in cattle and sheep, veterinarians decided to investigate SBV as a possible etiology. Serum samples from the 3-month-old puppy and the dam were tested by virus neutralization test (VNT), according to the protocol used for ruminant serum. The results were negative for the puppy but positive (titer 128) for the mother. Specific competitive SBV ELISA (IDVet, Montpellier, France) against the SBV N protein showed similar results. Real-time reverse transcription PCR (RT-PCR) was performed (3) to detect the presence of the SBV genome in the cerebellum. Because the sample was paraffin-embedded, RNA was extracted from 5-µm sections, as described (4). All of the extracted cerebellum sections had positive test results (cycle threshold range 33−36); the extraction and PCR controls all showed negative results. To confirm these positive results, conventional RT-PCR was used to amplify a 573-nt sequence of the SBV S segment. The amplification product was sequenced, and a BLAST analysis was performed (www.ncbi.nlm.nih.gov/BLAST). An identity of 100% was obtained with the SBV small gene segment from a ruminant (GenBank accession no. {type:entrez-nucleotide,attrs:{text:KC108860,term_id:443498566,term_text:KC108860}}KC108860). An immunohistochemical assay was also performed; the result was negative. The remaining 7 female dogs in the breeding kennel were tested for SBV in October 2012; 1 showed positive test results by VNT (titer 256), which confirmed that SBV was circulating in the kennel. This positive dam had a litter of puppies in December 2012, but no signs developed, and the puppies were not tested. In March 2013, repeat testing was done on serum samples from the 2 dogs that had shown positive results. Results for both animals were positive by VNT (titers 32 for the dam and 128 for the other dog) and ELISA. Taken together, specific SBV antibodies in the mother and the SBV genome in her puppy suggest that these dogs experienced SBV infection. The absence of detectable SBV antibodies in the puppy in this investigation suggests that transplacental infection occurred before the onset of fetal immune competence. Maternal infection probably occurred in January or February 2012; entomologic monitoring conducted in France showed the presence of Culicoides spp. midges, a vector of SBV, during this period in northwestern France. In addition, because the puppies were born in March 2012 and SBV antibodies were still detectable in the mother in March 2013, the duration of SBV antibodies in dogs appears to be >1 year. In cattle and sheep, the SBV genome persists in an infected fetus and is detectable after birth by real-time RT-PCR, despite gestation length (5,6). Few reports on orthobunyavirus infections in dogs are available. Two serologic studies from the United States (7) and Mexico (8) found antibodies against La Crosse virus, South River virus, and Jamestown Canyon virus in dogs. Two other reports described cases in which La Crosse virus was detected in canine littermates who had clinical encephalitis (9) or neurologic disorders (10). It is unclear if the apparent SBV infection we detected in these dogs was an isolated event or if other cases occurred elsewhere but were not detected because they were not investigated. Further serologic and clinical surveys are needed to estimate SBV prevalence in dogs and the virus’ involvement in the occurrence of neurologic signs in puppies.

High resolution 3D mapping of soil organic carbon in a heterogeneous agricultural landscape

Soil organic carbon (SOC) is a key element of agroecosystems functioning and has a crucial impact on global carbon storage. At the landscape scale, SOC spatial variability is strongly affected by natural and anthropogenic processes and linear anthropogenic elements (such hedges or ditches). This study aims at mapping SOC stocks distribution in the A-horizons for a depth up to 105cm, at a high spatial resolution, for an area of 10km2 in a heterogeneous agricultural landscape (North-Western France). We used a data mining tool, Cubist, to build rule-based predictive models and predict SOC content and soil bulk density (BD) from a calibration dataset at 8 standard layers (0 to 7.5cm, 7.5 to 15cm, 15 to 30cm, 30 to 45cm, 45 to 60cm, 60 to 75cm, 75 to 90cm and 90 to 105cm). For the models calibration, 70 sampling locations were selected within the whole study area using the conditioned Latin hypercube sampling method. Two independent validation datasets were used to assess the performance of the predictive models: (i) at landscape scale, 49 sampling locations were selected using stratified random sampling based on a 300-m square grid; (ii) at hedge vicinity, 112 sampling locations were selected along transects perpendicular to 14 purposively chosen hedges. Undisturbed samples were collected at fixed depths and analysed for BD and SOC content at each sampling location and continuous soil profiles were reconstructed using equal-area splines. Predictive environmental data consisted in attributes derived from a light detection and ranging digital elevation model (LiDAR DEM), geological variables, land use data and a predictive map of A-horizon thickness. Considering the two validation datasets (at landscape scale and hedge vicinity), root mean square errors (RMSE) of the predictions, computed for all the standard soil layers (up to a depth of 105cm), were respectively 7.74 and 5.02gkg−1 for SOC content, and 0.15 and 0.21gcm−3 for BD. Best predictions were obtained for layers between 15 and 60cm of depth. The SOC stocks were calculated over a depth of 105cm by combining the prediction of SOC content and BD. The final maps show that the carbon stocks in the soil below 30cm accounted for 33% of the total SOC stocks on average. The whole method produced consistent results between the two predicted soil properties. The final SOC stocks maps provide continuous data along soil profile up to 105cm, which may be critical information for supporting carbon policy and management decisions.

Forecasting animal migration using SARIMAX: an efficient means of reducing silver eel mortality caused by turbines

Hydroelectric power plants are often considered a major cause of mortality for migra- tory fish. The endangered status of European eels Anguilla anguilla forces managers to make efforts to reduce this mortality. Among the mitigation measures used, turbine shutdowns appear to be an efficient method, but they involve a substantial financial loss for hydropower producers. To optimise the use of turbine shutdowns, the present study aimed to provide a precise but simple forecast of the migration peaks of migrant silver eels. We first developed a model to forecast silver eel migration using SARIMAX models and real biological data of silver eel migration from 2 fish- ing sites in Brittany (north-western France). This model combines exogenous covariates and past biological data to forecast future migrations. We then evaluated this model with several years of biological data from the same trap sites, based on the decision criterion that turbines should be shut down when the number of silver eels forecasted by our model represents >10% of the mean annual number of migrants. This model would have served to save 90 and 70% of eels on the Oir and Scorff Rivers, respectively, with only 3.3 to 5.6 turbine shutdowns per year on average. Initial shutdowns would have lasted 1 wk, but this study also showed that the duration of turbine shut- downs could be reduced to 2 d without a significant decrease in efficiency. SARIMAX models reduce the influence of exogenous factors in forecasting outcomes, these being the most variable factors in the current context of climate change. This model appears to be a powerful tool for eco- logical forecasting of endangered species in the context of global warming.

Effects of field and landscape variables on crop colonization and biological control of the cabbage root fly Delia radicum

Agriculture intensification has deeply modified agroecosystems from field to landscape scales. To achieve successful pest control using natural enemies, understanding species interactions over all scales remains a challenge. Using the cabbage root fly as a model, we studied whether field and landscape characteristics influenced colonization and infestation of broccoli fields by the pest and its control by natural enemies. We also determined whether species of different trophic level or host specialization would respond to environmental characteristics at the same spatial extent. During a multiple-species and multiple-spatial extent study in northwestern France, we recorded pest colonization and infestation in 68 fields, collected associated natural enemies and assessed crop damages. In each field, we considered management practices and characterized the surrounding landscape in 50–500 m-wide buffers. Our main findings are that Delia radicum and its main natural enemies respond to both field and landscape characteristics. Semi-natural areas supported both crop colonization by pests and natural enemy action. The pest and its enemies differed in their responses to field or landscape variables. Landscape elements such as field banks favored the movement of the pest while impeding the movement of some natural enemies. Pest pressure did not increase with the neighboring density of Brassica crops. The presence of natural enemies did not reduce crop damage but reduced pest emerging rates. Finally, specialist parasitoids responded to the landscape at larger spatial extents than generalists. These results outline the complexity of improving pest control through landscape management.

Species’ thermal preferences affect forest bird communities along landscape and local scale habitat gradients

The spatial distributions of species, and the resulting composition of local communities, are shaped by a complex interplay between species’ climatic and habitat preferences. We investigated this interaction by analyzing how the climatic niches of bird species within given communities (measured as a community thermal index, CTI) are related to vegetation structure. Using 3129 bird communities from the French Breeding Bird Survey and an information theoretic multimodel inference framework, we assessed patterns of CTI variation along landscape scale gradients of forest cover and configuration. We then tested whether the CTI varies along local scale gradients of forest structure and composition using a detailed data set of 659 communities from six forests located in northwestern France. At landscape scale, CTI values decreased with increasing forest cover, indicating that bird communities were increasingly dominated by cold‐dwelling species. This tendency was strongest at low latitudes and in landscapes dominated by unfragmented forest. At local scale, CTI values were higher in mature deciduous stands than in conifer or early stage deciduous stands, and they decreased consistently with distance from the edge of forest. These trends underpin the assertion that species’ habitat use along forest gradients is linked with their climatic niche, although it remains unclear to what extent it is a direct consequence of microclimatic variation among habitats, or a reflection of macroscale correlations between species’ thermal preferences and their habitat choice. Moreover, our results highlight the need to address issues of scale in determining how habitat and climate interact to drive the spatial distribution of species. This will be a crucial step towards accurate predictions of changes in the composition and dynamics of bird communities under global warming.

Promotion and shoppers' impulse purchases: the example of clothes

Purpose– This paper draws attention to the fact that impulse buying is common behaviour among modern shoppers and that a consumer's impulse purchases of items such as clothes may be a result of the retailers' promotional activities. The purpose of this paper is therefore to investigate how promotion through channels such as direct-mail marketing, TV commercials and special in-store displays affects consumers' impulse purchases of clothes.Design/methodology/approach– Data for the testing of five hypotheses was collected by distributing a questionnaire to randomly selected households in North Western France and Northern Sweden. The data collection rendered 493 complete questionnaires, of which 332 were from France and 161 from Sweden. Seemingly unrelated regression (SUR) is the principal estimation technique.Findings– The results suggest that shoppers with a positive attitude towards direct-mail marketing and TV commercials also respond positively to in-store promotion. Hence, there are interactive effects between the three promotional channels that increase shoppers' general impulse purchase tendency. Furthermore, the findings demonstrate that the frequency of exposure to in-store promotion has a significant effect on this tendency.Originality/value– This paper contributes to extant knowledge on impulse buying behaviour by examining the product-specific impulse tendency, which is defined as the degree to which consumers make impulse purchases of a particular product category.

Industrial Symbiosis Optimization Control Model for the exchanges of the material/energy flows in an industrial production park

The focus on the green manufacturing production is becoming more and more important in France. Le Havre is a city located in the north-western France, which concentrates more than a third of French refining capacity. However, simultaneously, the pollution caused by industries needs to be controlled. Furthermore, Le Havre would like to be the first city that does really ecological industrial park in France. Industrial symbiosis is a key concept of industrial ecology, which studies the physical flows of materials and energy in the local industrial systems. There are few studies that support the assumption of economic and environmental benefits of industrial symbiosis. So, in order to have a WIN-TO-WIN situation, we proposed a mathematical optimization control model. The model will help the manufacturing industries to reduce related costs, and the negative environmental impact would be decreased simultaneously. Best to our knowledge, currently, it does not exist any other general mathematical optimization model for constructing and optimizing an eco-industrial park.

Emergence of a new lagovirus related to rabbit haemorrhagic disease virus

Since summer 2010, numerous cases of Rabbit Haemorrhagic Disease (RHD) have been reported in north-western France both in rabbitries, affecting RHD-vaccinated rabbits, and in wild populations. We demonstrate that the aetiological agent was a lagovirus phylogenetically distinct from other lagoviruses and which presents a unique antigenic profile. Experimental results show that the disease differs from RHD in terms of disease duration, mortality rates, higher occurrence of subacute/chronic forms and that partial cross-protection occurs between RHDV and the new RHDV variant, designated RHDV2. These data support the hypothesis that RHDV2 is a new member of the Lagovirus genus. A molecular epidemiology study detected RHDV2 in France a few months before the first recorded cases and revealed that one year after its discovery it had spread throughout the country and had almost replaced RHDV strains. RHDV2 was detected in continental Italy in June 2011, then four months later in Sardinia.

Une occupation de l’extrême fin du Paléolithique dans la vallée de l’Escaut à Proville (Nord) « le Bois Chenu »

At the end of the 1960s, pedestrian surveys yielded a homogeneous lithic assemblage from the bottom of a silty slope in contact with the alluvial plain of the river Scheldt. The morpho-technological features of the industry allowed it to be assumed that it belonged to the Epi-Ahrensburgian culture, a tradition mainly represented from the Loire Valley in France to northern Germany and southern England, from the end of the Younger Dryas to the early Pre-Boreal. The surveys undertaken in 2008, on a cultivated field south of the collection site, now urbanized, revealed a series of occupations at the bottom of this slope dating from the Late Palaeolithic to recent protohistoric periods. A concentration of lithic artefacts undoubtedly belonged to the same technical tradition as the series found on the surface. The excavation campaigns in 2009 and 2010 helped to define a Final Palaeolithic spatial entity and provided elements for technological, chrono-typological and spatial interpretations. The partial refittings of some blocks contribute to a better understanding of the strategy developed for obtaining standardized blades. The careful management of the siliceous material is exclusively oriented towards the production of laminar or lamellar supports. This technical process is highly representative of the ‘ Belloisian’ tradition. The initial blocks were prepared by a specific method using a hard stone hammer (flint). Blades and bladelets were removed by a sandstone hammer according to a bipolar process and after intense preparation of striking platform edges by abrasion. The toolkit refers to a technical environment now better understood thanks to research conducted over the past 20 years with regard to this techno-complex in north-western France and despite the obvious presence of intrusive Mesolithic elements.

New record of Discradisca (Brachiopoda: Discinidae) from the Early Miocene of the Aquitaine Basin, south-western France

The linguliform inarticulate brachiopod genus Discradisca Stenzel, 1964 has been identified for the first time from the Early Burdigalian (Early Miocene) sandy deposits of the Aquitaine Basin, south-western France. The species studied here, D. multiradiata (de Morgan, 1915), originally described from the Middle Miocene of the Loire Basin, north-western France, is characterized by a small size, ornamentation of numerous (up to 100), fine but distinct and beaded tuberculate ribs, and an apex situated subposteriorly to subcentrally. The ecological and taphonomic aspects of this species are also presented. The attribution of some previously described Discinisca Dall, 1871 species from the Tertiary to the genus Discradisca is discussed.

The influence of salina landscape structures on terrestrial bird distribution in the Guérande basin (Northwestern France)

Capsule The salinas of the Guérande basin show highly fragmented landscapes that significantly structure the distribution of terrestrial birds. Aim To test the potential influence of landscape structures of a fragmented landscape on the distribution of terrestrial birds. Methods The salinas were mapped using a Geographical Information System and landscape metrics were calculated to quantify landscape structures. Birds were surveyed with a point count method. Multivariate analyses and multiple linear regressions were used to test for potential links between landscape metrics and bird distribution. Results The landscape structures of the salinas influenced bird assemblages significantly. The core of the salinas, with more-fragmented and less-diverse landscapes, contained the lowest abundance, richness and diversity of birds, but this assemblage tended to be homogeneous and distinct. Bird abundance, richness and diversity mainly increased with landscape richness and diversity, the terrestrial area available and the proximity to the continental domain. Conclusion This study is the first to demonstrate and quantify the influence of salina landscape structures on terrestrial bird assemblages.

Typification ofNitella gracilis(Sm.) C. Agardh var.confervaceaBrébisson (=N.confervacea(Brébisson) A. BraunexLeonhardi) with Remarks on Its Nomenclatural History

The correct name of the species of Nitella known as the ‘Least Stonewort’ has long been under debate. The problem has now been resolved as Nitella confervacea (Brébisson) A. Braun ex Leonhardi. This taxon, once thought to be an endemic of northwestern France, was neglected for a long time. The basionym Nitella gracilis var. confervacea Brébisson and other taxa connected to this name are typified, and their taxonomic status is assessed.

Correlation between Environmental Relative Moldiness Index (ERMI) values in French dwellings and other measures of fungal contamination

The Environmental Relative Moldiness Index (ERMI) is a DNA-based metric developed to describe the fungal contamination in US dwellings. Our goal was to determine if the ERMI values in dwellings in north western France were correlated with other measures of fungal contamination. Dust and air samples were obtained from 40 dwellings and analyzed by quantitative PCR and/or by culturing. These dwellings were also inspected and the amount of visible fungal growth estimated in m2. The ERMI values in these dwellings ranged from –2.7 to 28.8 and the fungal contamination estimates ranged from 0 to 20m2. The 40 dwellings were divided into those with a low (<6) or high (>8) ERMI values (n=20 in each). The average ERMI value was 15.70 for the high ERMI compared to 2.68 for the low ERMI dwellings. ERMI values were correlated (significant Kendall's tau values) with concentrations of fungi in air samples analyzed by QPCR or culturing. ERMI values were also correlated (significant Kendall's tau values) with the visible estimates of fungal contamination. Older dwellings were more likely to have higher ERMI values. These results suggest that the ERMI dust sample, which is quick and easy to collect, may be useful in making decisions about reducing fungal exposures in homes.

Spatial organization of earthworm assemblages in pastures of northwestern France

Studying spatial patterns of soil engineers has become an important issue that may contribute to a better understanding of soil functioning. We investigated the spatial patterns of earthworm species assemblages in a recently settled and an old temperate pasture. Earthworms were sampled following a spatially explicit sampling design. Data were analysed using Spatial Analysis by Distance IndicEs methods to describe the main characteristics of earthworm spatial patterns: aggregation index, patch and/or gap number and size, and the frequencies of species association or dissociation. Ten lumbricid species composed the earthworm assemblages in both pastures, some of them displaying a spatial distribution characterized by clusters with areas of patches and gaps. By comparing aggregation indices between the pastures, an increase of the spatial organization level in the community was observed in the old pasture. We also observed differences between the pastures in the number of aggregated species, cluster characteristics, ratio between spatial association/dissociation and spatial overlap. We also found some significant relationships between species pairs that were already described in the literature, enabling us to discuss the possible nature of interactions. Our results suggest that earthworm spatial distribution and community assembly are likely driven by interspecific interactions at the local scale.

Links between NAO fluctuations and inter-annual variability of winter-months precipitation in the Seine River watershed (north-western France)

The inter-annual to multi-decadal winter variability (DJFM) of precipitation on the Seine River watershed (France) was analysed using continuous wavelet transform analysis and compared to the winter North Atlantic Oscillation Index (NAOI). Nine weather stations were used over the 1951 to 2004 period and confirmed the homogeneity of inter-annual fluctuations for all stations but one. Wavelet coherence between SLP over the Icelandic and Azores regions and precipitation highlighted coherence for different scales of variability according to the centre of action considered. Segmentation and wavelet analysis and coherence between precipitation and NAOI over a long period of time (1873–2004) showed: i) increasing variability across the last century at most time scales, especially for NAOI; ii) the existence of change points for the mean and variance of both signals; iii) overall discontinuity of the coherence whatever the scale considered, especially between ∼1910 and ∼1955 for inter-decennial to pluri-decennial scales.

Adapting the coupled hydrological model ISBA-TOPMODEL to the long-term hydrological cycles of suburban rivers: Evaluation and sensitivity analysis

The hydrological model ISBA-TOPMODEL, initially developed for large rural basins prone to flash floods, has been adapted to suburban basins. Impervious surfaces were taken into account assuming very low infiltration, production of runoff drained through the sewer network when the maximal surface stock capacity is exceeded and groundwater infiltration. This model was evaluated on a French basin, located in the northwestern France, within a suburb of the city of Nantes. A sensitivity study was first performed on the major urban parameters in order to determine which ones had to be calibrated. A ten-year period (2001–2010) was simulated, with the first three years for calibration purposes and the last seven for the actual evaluation. The statistical criteria reveal that the model tends to underestimate total discharge during dry periods while it overestimates discharge during wet weather. The underestimation seems to be caused by an unrealistic deep drainage through the soil, whereas the overestimation can be attributed to impervious surface runoff overestimation. Nevertheless, over the entire simulated period, the statistical criteria still indicate satisfactory results.