Search results for "FLOW"
showing 10 items of 5185 documents
Spatial heterogeneity of spring phytoplankton in a large tropical reservoir: could mass effect homogenize the heterogeneity by species sorting?
2018
Reservoirs are river–lake hybrid ecosystems characterized by a marked longitudinal zonation and variable flushing rates depending on the use of stored waters. The structure of their phytoplankton is therefore subjected to the interplay between the environmental conditions of the different zones (species sorting) and the strength of the unidirectional flow (mass effect). The spatial distribution of spring phytoplankton was investigated in a tropical reservoir across its different zones. Phytoplankton displayed heterogeneous spatial patterns from the turbulent, nutrient-rich riverine zones to the relatively stable lacustrine zone. The analysis of this spatial heterogeneity revealed the relati…
Impact of Freshwater Inflow From the Volturno River on Coastal Circulation
2020
The coastal area located in front of the Volturno river's estuary (Gulf of Gaeta, central-eastern Tyrrhenian Sea) has been synoptically sampled during seven surveys, between June 2012 and October 2014. The vertical profiles of temperature and salinity have been acquired on a high resolution nearly-regular grid, in order to describe the spatial and temporal variability of the water masses characteristics. Moreover, to provide a first assessment of the steady circulation at small scale, the three-dimensional velocity field associated to each survey has been obtained through the full momentum equations of the Princeton Ocean Model. The data analysis has shown the entire water column characteri…
Colonisation and diversification of the Zenaida dove (Zenaida aurita) in the Antilles: phylogeography, contemporary gene flow and morphological diver…
2013
12 pages; International audience; Caribbean avifaunal biogeography has been mainly studied based on mitochondrial DNA. Here, we investigated both past and recent island differentiation and micro-evolutionary changes in the Zenaida Dove (Zenaida aurita) based on combined information from one mitochondrial (Cytochrome c Oxydase subunit I, COI) and 13 microsatellite markers and four morphological characters. This Caribbean endemic and abundant species has a large distribution, and two subspecies are supposed to occur: Z. a. zenaida in the Greater Antilles (GA) and Z. a. aurita in the Lesser Antilles (LA). Doves were sampled on two GA islands (Puerto Rico and the British Virgin Islands) and six…
New insight into the colonization processes of common voles: inferences from molecular and fossil evidence.
2008
Biologie et Gestion des Populations, Campus International de Baillarguet, Montferrier/Lez, FranceElucidating the colonization processes associated with Quaternary climatic cycles is important in order to understand the distribution of biodiversity and the evolutionary potential of temperate plant and animal species. In Europe, general evolutionary scenarios have been defined from genetic evidence. Recently, these scenarios have been challenged with genetic as well as fossil data. The origins of the modern distributions of most temperate plant and animal species could predate the Last Glacial Maximum. The glacial survival of such populations may have occurred in either southern (Mediterranea…
GenExP, un logiciel simulateur de paysages agricoles pour l'étude de la diffusion de transgènes
2007
; The software GENEXP allows to simulate 2-dimensional agricultural landscapes by using a traditional algorithmic geometry. Based on real or realistic field-patterns, GENEXP provides multiannual maps of agricultural landscapes, which are used by softwares simulating the dispersal of GM pollen grains and seeds at various scales.; GENEXP est un simulateur de paysages agricoles qui engendre des découpages parcellaires en utilisant une géométrie algorithmique classique. GENEXP fournit, sur la base de parcellaires réels ou réalistes, des cartes pluriannuelles de paysages agricoles utilisables par des logiciels qui simulent la dispersion des pollens et des graines d'OGM à différentes échelles.
Comparative host–parasite population structures: disentangling prospecting and dispersal in the black-legged kittiwake Rissa tridactyla
2005
Although much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black-legged kittiwake ( Rissa tridactyla ) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species’ range and, at the same time, collected individuals of one of its common ectoparasites, the tick Ixodes uriae . Parasites were …
Comparative study of the efficiency of buffer zones and harvest discarding on gene flow containment in oilseed rape. A modelling approach
2009
International audience; Oilseed rape (OSR) genes can escape fields in space via pollen and seeds and in time via volunteers resulting from seeds lost before or during oilseed rape harvests. Previous simulation studies and field observations showed that co-existence at the landscape level of contrasting OSR varieties such as genetically modified (GM) and non-GM varieties require costly measures that are difficult to implement, such as isolation distances between OSR fields and stringent volunteer control in all fields and road margins. In the present study, two local strategies, non-GM buffer zones aroundGMfields and discarding the harvest of boundary plants of non-GM fields, were tested in …
Genetic roadmap of the Arctic: plant dispersal highways, traffic barriers and capitals of diversity.
2013
This is the peer reviewed version of the following article: Eidesen, P.B., Ehrich, D., Bakkestuen, V., Alsos, I.G., Gilg, O., Taberlet, P. & Brochmann, C. (2013). Genetic roadmap of the Arctic: plant dispersal highways, traffic barriers and capitals of diversity. New Phytologist, 200(3), 898-910. https://doi.org/10.1111/nph.12412, which has been published in final form at https://doi.org/10.1111/nph.12412. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. We provide the first comparative multispecies analysis of spatial genetic structure and diversity in the circumpolar Arctic using a common strategy for sam…
Assessing the indirect and long-term ecological impacts of innovation in agriculture is a real challenge: the GM example
2003
All innovation in agriculture constitutes a significant and complex ecological disturbance, even if limited to a single and simple action. Indeed, whatever the nature and objective of the action, a large number of ecological processes are affected and numerous discontinuities may occur within the agro-ecosystem, in both time and space. As the GMO example illustrates, it is not sufficient to focus on direct effect of innovation, it is necessary to forecast mid- and long-term impacts of innovation with respect to the environment. Modelling phenomena appear then to be a key element to achieve this goal.
Can the problem of hybridization in threatened species be evaluated using a fieldwork research? A case study in snapdragons
2019
Abstract Hybridization, natural or artificial, is considered disadvantageous for species biodiversity when it threatens the population integrity of endangered species. Frequently, studies investigating whether hybridization poses a legitimate risk to rare species are based on genetic data obtained in molecular biology laboratories. In this study, we used field research to approach the problem that hybridization could cause for the viability of a population of a rare species and to be able to propose the most appropriate initial conservation strategy. Specifically, using the model genus Antirrhinum, the reproductive barriers between the rare A. pulverulentum and its common congener A. litigi…