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Vincennes, France

The Water Framework Directive and the French law related to the implementation of the "Grenelle de l'environnement" process plan to ensure, by 2012, the protection of about 500 catchments for drinking water production (called "Grenelle"] which are among the most affected catchments by non-point source pollution. In order to achieve this objective, the Ministries of Ecology and Agriculture, Onema, and the water agencies have been working with research institutes to provide methodological tools that will be used to identify relevant measures. A technical working group on catchment protection for drinking water production affected by non-point source pollution has been created in early 2010 under Onema's leadership. The aim of this technical working group is to identify gaps and potential Research and Development (R&D) studies needed to improve the making of action plans by integrating technical and socio-economical topics. An analysis of R&D studies about this topic has been undertaken. In addition, new research studies are launched. Since 2007, BRGM has developed a delineation and vulnerability mapping guide for catchment for drinking water production. It has performed a feedback, updated this guide and analysed the efficiency of action plans in terms of water quality. At the same time, a similar study was performed by Irstea on water supply catchments where runoff and subsurface flows control the pollutant transfers. Furthermore, a collaborative study between Irstea and BRGM was carried out to develop a methodology based on the pollutant transfer typology allowing to select appropriate actions. INRA is responsible for carrying out a typology of the "Grenelle" water supply catchments (state of water pollution, agricultural practices, local socio-economical situations...) and for developing a thorough study about actions implemented on selected water supply catchments. Given the relatively short deadlines for "Grenelle" water catchments, these studies will also be useful for other water catchments that are vulnerable to non-point source pollution and for improving the existing or future action plans. Source

Tomanova S.,Delegation Interregionale Center | Tedesco P.A.,French Natural History Museum | Roset N.,Onema | Berrebi dit Thomas R.,Onema | Belliard J.,IRSTEA
Fisheries Management and Ecology | Year: 2013

Compared with small rivers and streams, the study of fish communities in large rivers remains challenging as spatial and temporal data variability can be greatly influenced by sampling strategy and operator choice. In an attempt to limit this variability, a new sampling protocol for fish communities in medium- to large-sized rivers was developed, based on point sampling by electric fishing and using standardised procedures and effort. Here, change in data quality (assemblage abundance, richness, structure and biotic index) with increasing sampling effort (from 1 to 100 sampling points) was evaluated. A total of 75 sampling points are proposed as the standard number of samples per site. Broadly, the results show that the application of 75 sampling points provides a reproducible representation of fish community structure in medium and large rivers, with little additional information provided by further sampling except under certain conditions, when 100 points are recommended to maintain data quality. © 2013 John Wiley & Sons Ltd. Source

Rejiba F.,CNRS Transfers and Interactions in Hydrosystems and Soils | Bobee C.,CEA Saclay Nuclear Research Center | Maugis P.,Onema | Camerlynck C.,CNRS Transfers and Interactions in Hydrosystems and Soils
Journal of Applied Geophysics | Year: 2012

Local agriculture in Senegal is dependent on truck farming, which is concentrated in the narrow interdunal zone of peat deposits, called "niayes". The viability of the niayes significantly depends on the sand dune aquifer, as a consequence of recent over-pumping. In the present paper, we discuss the ability of GPR to locate the water table, in a highly vegetated interdunal area which includes peat fields, as well as internal dips, which were shown to be complex. Three profiles determined in the interdunal zone have been associated with several boreholes. Analysis of the radargrams clearly shows that 1) the presence of dense vegetation is not a penalising factor; 2) phase inversion in the measured signal could be useful in distinguishing between the presence of a significant water contrast, and that of a strong stratigraphic reflector; 3) in sand dunes, the electromagnetic contrast resulting from a wetting front is likely to be of the same order as that of the water table. The outcome of this study may provide clues to the characterisation and management of water resources in niayes area. © 2011 Elsevier B.V.. Source

Blanchet S.,French National Center for Scientific Research | Blanchet S.,CNRS Biological Evolution and Diversity Laboratory | Reyjol Y.,Onema | April J.,Laval University | And 4 more authors.
Global Ecology and Biogeography | Year: 2013

Aim: We investigated the relationship between geographic range size (GRS), longitude and latitude (Rapoport's rule) in Canadian freshwater fishes. We tested hypotheses regarding the phenotypic and phylogenetic determinants of GRS to unravel processes driving the spatial patterns of GRS in Canada. Because GRS is negatively correlated with extinction risk, we also aimed at identifying biological proxies that may be used to predict extinction risks. Location: North-America, Canadian Shield. Methods: We built a database combining range area, seven ecological traits, and a molecular phylogeny for native Canadian freshwater fishes. We tested latitudinal and longitudinal patterns in GRS by the mean of Pearson correlations. We combined phylogenetic generalized least squares (PGLS) models and a model selection procedure to tease apart hypotheses (and hence ecological traits) that best explained GRS in our dataset. PGLSs were also used to explore relationships between ecological traits, phylogeny, and species mid-range latitude and longitude. Partial regressions were used to determine direct and indirect relationships driving spatial patterns of GRS in Canadian freshwater fishes. Results: There was a significant and positive correlation between GRS, latitude and longitude. According to PGLSs, three ecological traits, related to the habitat use, migratory and thermal tolerance hypotheses, were significantly correlated with GRS, mid-range longitude and mid-range latitude. Two traits related to locomotion were further related to GRS. There was no phylogenetic effect on GRS (i.e. no phylogenetic conservatism). Partial regressions revealed complex direct and indirect relationships between ecological traits, mid-range latitude, mid-range longitude and GRS. Main conclusions: Our results show that traits related to the ability to use dispersal corridors, as well as traits directly related to mobility, are useful in understanding biodiversity patterns such as Rapoport's rule. However, because of a weak explanatory power, we conclude that using biological proxies of GRS to predict species at risk of extinction would be premature. © 2013 John Wiley & Sons Ltd. Source

Dekker W.,Swedish University of Agricultural Sciences | Beaulaton L.,Onema | Beaulaton L.,French National Institute for Agricultural Research
ICES Journal of Marine Science | Year: 2015

Few fish stocks are as influenced by (intentional and inadvertent) human impacts as the European eel, all across the continent. The dynamics of this stock, however, are poorly understood - neither the causes of the historically low abundance, nor minimal protection levels, are beyond discussion. Rather than analysing contemporary processes, this article turns back in time - two centuries or more - unravelling historical abundances and distribution patterns; reviewing historical actions and objectives; and discussing technical developments and scientific advice - picturing the slippery slope the eel stock has come down from. The first claim, that the continental stock was in decline, dates from the early 1800s; stock-enhancement actions were initiated shortly after. Diffuse objectives, technical innovations, eternal optimism, and - above all - no quantification impede the exact evaluation of historical reports. After 1950, when quantification improved, a slow but consistent decline was observed, but it is only two decades after the crash in glass eel recruitment (in 1980), that protection plans addressed the bad status of the stock. A slippery slope, full of pitfalls - yet, we now observe several years of increasing recruitment. © 2015 International Council for the Exploration of the Sea 2015. All rights reserved. Source

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