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Auteur Walker, T.R.; Grant, J.; Weise, A.M.; McKindsey, C.W.; Callier, M.D.; Richard, M.
Titre Influence of suspended mussel lines on sediment erosion and resuspension in Lagune de la Grande Entree, Iles-de-la-Madeleine, Quebec, Canada Type Article scientifique
Année 2014 Publication Revue Abrégée Aquaculture
Volume 433 Numéro Pages 450-457
Mots-Clés Aquaculture; Biodeposits; biogeochemical fluxes; culture; dynamics; intertidal cohesive sediments; lagoon; Mytilus; Mytilus edulis; Particle; rates; Resuspension; Sediment erosion; Shear velocity; size; stability
Résumé Downward fluxes of organically rich biodeposits under suspended mussel lines can cause benthic impacts such as changes in benthic community structure or microbial mat production. Quantifying sediment erosion in these coastal ecosystems is important for understanding how fluxes of organic matter and mussel biodeposits contribute to benthic pelagic coupling. Critical shear velocity (u(crit)*(t)), erosion rates and particle size distributions of resuspended sediment were measured at four stations distributed along a transect perpendicular to a mussel farm in Lagune de la Grande Entree, Iles-de-la-Madeleine (Quebec, Canada). Stations were selected underneath the outer-most mussel line (0 m) and at distances of 15,30 m and at a reference station (500 m) further along the transect. Shear velocity was measured using a calibrated portable Particle Erosion Simulator, also referred to as the BEAST (Benthic Environmental Assessment Sediment Tool). Undisturbed sediment cores obtained by divers were exposed to shear stress to compare differences between stations. Erosion sequences indicated no significant differences in u(crit)* between stations, but there were significant differences in erosion rates beneath mussel lines compared to other stations. Erosion rates were the highest in cores from beneath mussel lines, but paradoxically had the lowest u(crit)* Mean erosion rates at u*crit varied between 25 and 47 g m(-2) min(-1) and critical erosion thresholds varied between 1.58 and 1.73 cm s(-1), which compare with intensive mussel culture sites elsewhere in eastern Canada. Significant differences existed in biotic and abiotic properties of sediments which could explain variation in maximum erosion rates within and between stations. Particle sizes measured by videography of resuspended sediment at different shear velocities ranged from 02 to 3.0 mm. Quantifying sediment erosion from intact marine sediments helps to improve our mechanistic understanding of these processes, and the BEAST further contributes to predictive capability in benthic pelagic coupling modeling. (C) 2014 Elsevier B.V. All rights reserved.
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Notes <p>ISI Document Delivery No.: AQ1GH<br/>Times Cited: 0<br/>Cited Reference Count: 39<br/>Walker, Tony R. Grant, Jon Weise, Andrea M. McKindsey, Christopher W. Callier, Myriam D. Richard, Marion<br/>Natural Sciences and Engineering Research Council of Canada (NSERC); Aquaculture Collaborative Research and Development Program (ACRDP); Societe de Development de l'Industrie Maricole (SODIM); Fisheries and Oceans Canada<br/>We thank MAPAQ and B. Hargrave for the collaboration and C. Eloquin and associates for the permission to use their site. Funding was provided by the Aquaculture Collaborative Research and Development Program (ACRDP), the Societe de Development de l'Industrie Maricole (SODIM) and the Fisheries and Oceans Canada. We thank B. Schofield and M. Merrimen for the fabrication of the BEAST which formed part of the equipment necessary for the Canadian Arctic Shelves Exchange Study (CASES), a Research Network funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).<br/>Elsevier science bv<br/>Amsterdam</p> Approuvé pas de
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Auteur Villeger, S.; Grenouillet, G.; Brosse, S.
Titre Functional homogenization exceeds taxonomic homogenization among European fish assemblages Type Article scientifique
Année 2014 Publication Revue Abrégée Global Ecology and Biogeography
Volume 23 Numéro 12 Pages 1450-1460
Mots-Clés beta-diversity; exotic species; functional diversity; Non-native species; taxonomic dissimilarity; translocation
Résumé Aim Human activities and the consequent extirpations of native species and introductions of non-native species have been modifying the composition of species assemblages throughout the world. These anthropogenic impacts have modified the richness of assemblages as well as the biological dissimilarity among them. However, while changes in taxonomic dissimilarity (i.e. accounting for species composition) have been assessed intensively during the last decade there are still few assessments of changes in functional dissimilarity (i.e. accounting for the diversity of biological traits). Here, we assess the temporal changes in both taxonomic and functional dissimilarities for freshwater fish assemblages across Europe. Location Western Palaearctic, 137 river basins. Methods The Jaccard index was used to quantify the changes in both taxonomic and functional dissimilarity. We then partitioned dissimilarity to extract its turnover component and measured the changes in the contribution of turnover to dissimilarity. Results Functional homogenization exceeded taxonomic homogenization six-fold. More importantly, we found only a moderate positive correlation between these changes. For instance, 40% of assemblages that experienced taxonomic differentiation were actually functionally homogenized. Taxonomic and functional homogenizations were stronger when the historical level of taxonomic dissimilarity among assemblages was high and when a high number of non-native species were introduced in the assemblages. Moreover, translocated species (i.e. non-native species originating from Europe) played a stronger role than exotic species (i.e. those coming from outside Europe) in this homogenization process, while extirpation did not play a significant role. Main conclusions Change in taxonomic diversity cannot be used to predict changes in functional diversity. In addition, as functional diversity has been proven to be a better indicator of ecosystem functioning and stability than taxonomic diversity, further studies are required to test the potential effects of functional homogenization at the local scale.
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ISSN 1466-8238 ISBN Médium
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Auteur Valladares, F.; Matesanz, S.; Guilhaumon, F.; Araujo, M.B.; Balaguer, L.; Benito-Garzon, M.; Cornwell, W.; Gianoli, E.; van Kleunen, M.; Naya, D.E.; Nicotra, A.B.; Poorter, H.; Zavala, M.A.
Titre The effects of phenotypic plasticity and local adaptation on forecasts of species range shifts under climate change Type Article scientifique
Année 2014 Publication Revue Abrégée Ecology Letters
Volume 17 Numéro 11 Pages 1351-1364
Mots-Clés change impacts; climate change; climate variability hypothesis; ecological niche models; edge populations; environments; evolution; genetic differentiation; global change; intraspecific variation; local adaptation; niche; phenotypic plasticity; population differentiation; quercus-coccifera; reaction norms; thermal tolerance; tree populations
Résumé Species are the unit of analysis in many global change and conservation biology studies; however, species are not uniform entities but are composed of different, sometimes locally adapted, populations differing in plasticity. We examined how intraspecific variation in thermal niches and phenotypic plasticity will affect species distributions in a warming climate. We first developed a conceptual model linking plasticity and niche breadth, providing five alternative intraspecific scenarios that are consistent with existing literature. Secondly, we used ecological niche-modeling techniques to quantify the impact of each intraspecific scenario on the distribution of a virtual species across a geographically realistic setting. Finally, we performed an analogous modeling exercise using real data on the climatic niches of different tree provenances. We show that when population differentiation is accounted for and dispersal is restricted, forecasts of species range shifts under climate change are even more pessimistic than those using the conventional assumption of homogeneously high plasticity across a species' range. Suitable population-level data are not available for most species so identifying general patterns of population differentiation could fill this gap. However, the literature review revealed contrasting patterns among species, urging greater levels of integration among empirical, modeling and theoretical research on intraspecific phenotypic variation.
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ISSN 1461-023x ISBN Médium
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Notes <p>ISI Document Delivery No.: AT8YX<br/>Times Cited: 4<br/>Cited Reference Count: 80<br/>Valladares, Fernando Matesanz, Silvia Guilhaumon, Francois Araujo, Miguel B. Balaguer, Luis Benito-Garzon, Marta Cornwell, Will Gianoli, Ernesto van Kleunen, Mark Naya, Daniel E. Nicotra, Adrienne B. Poorter, Hendrik Zavala, Miguel A.<br/>Spanish Ministry for Innovation and Science with the grant Consolider Montes [CSD2008 00040]; Community of Madrid grant REMEDINAL 2 [CM S2009 AMB 1783]; CYTED network ECONS [410RT0406]; Spanish Ministry of Economy and Competitiveness [1/SAE-SCTN/ALENT-07-0224-FEDER-001755, CGL2011-26852]<br/>This work was supported by the Spanish Ministry for Innovation and Science with the grant Consolider Montes [CSD2008 00040], the Community of Madrid grant REMEDINAL 2 [CM S2009 AMB 1783], and CYTED network ECONS (410RT0406). The Pinus sylvestris provenance tests used in this research are part of the Spanish Network of Genetic Trials (GENFORED). We thank all those involved in the establishment, maintenance and measurement of the trials. MBA also thanks the Portuguese IC&DT Call No 1/SAE-SCTN/ALENT-07-0224-FEDER-001755 and CGL2011-26852 project of the Spanish Ministry of Economy and Competitiveness for support of his research.<br/>Wiley-blackwell<br/>Hoboken</p> Approuvé pas de
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Auteur Triki, H.Z.; Daly-Yahia, O.K.; Malouche, D.; Komiha, Y.; Deidun, A.; Brahim, M.; Laabir, M.
Titre Distribution of resting cysts of the potentially toxic dinoflagellate Alexandrium pseudogonyaulax in recently-deposited sediment within Bizerte Lagoon (Mediterranean coast, Tunisia) Type Article scientifique
Année 2014 Publication Revue Abrégée Marine Pollution Bulletin
Volume 84 Numéro 1-2 Pages 172-181
Mots-Clés Alexandrium pseudogonyaulax; autocorrelation; bay; Benthic; blooms; cysts; dynamics; eutrophication; gonyaulax-excavata; gulf; Harmful algae; Mapping; Mediterranean Lagoon of Bizerte; resting cysts; Sediment characteristics; spatial-distribution; surface sediments
Résumé This study investigated the spatial distribution of Alexandrium pseudogonyaulax resting cysts in recently-deposited sediment of Bizerte lagoon (South-Western Mediterranean, Tunisia). This lagoon is the subject of many anthropogenic impacts, such as holding important fishing and aquaculture activities. A. pseudogonyaulax has been shown to produce Goniodomin A, which is a biologically-active compound. We showed that this dinoflagellate produces two types of resting cysts, which could be distinguished by the presence or the absence of a paratabulate wall. The average cyst density across the whole lagoon was rather high, reaching 639 cysts g(-1) of dry sediment (DS). Cyst densities varied widely among the sampled stations, with the highest density of 1685 cyst g(-1) DS being recorded at station 51 near a mussel farm. With respect to sediment characteristics, the highest cyst densities were found within silty sediments with high water content values. The distribution of A. pseudongoyaulax cysts in Bizerte lagoon appears to be related to hydrodynamic factors. (C) 2014 Elsevier Ltd. All rights reserved.
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Notes <p>ISI Document Delivery No.: AL0GF<br/>Times Cited: 0<br/>Cited Reference Count: 45<br/>Triki, Habiba Zmerli Daly-Yahia, Ons Kefi Malouche, Dhafer Komiha, Yosr Deidun, Alan Brahim, Mouldi Iaabir, Mohamed<br/>JEAI ECO-BIZ (Jeune Equipe Associee, Ecologie de la lagune de Bizerte) program – IRD (Institut Francais pour la Recherche et le Developpement), IRD; TOTAL Foundation<br/>This work benefitted from financial supports from the JEAI ECO-BIZ (Jeune Equipe Associee, Ecologie de la lagune de Bizerte) program funded by IRD (Institut Francais pour la Recherche et le Developpement), IRD also funded 2 months stay of Dr. Mohamed Laabir in Tunis (INAT). Thanks to TOTAL Foundation for funding LAGUNOTOX project which supported financially the stay of Mrs Triki-Zmerli in Montpellier.<br/>Pergamon-elsevier science ltd<br/>Oxford</p> Approuvé pas de
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Auteur Toussaint, A.; Beauchard, O.; Oberdorff, T.; Brosse, S.; Villeger, S.
Titre Historical assemblage distinctiveness and the introduction of widespread non-native species explain worldwide changes in freshwater fish taxonomic dissimilarity Type Article scientifique
Année 2014 Publication Revue Abrégée Global Ecology and Biogeography
Volume 23 Numéro 5 Pages 574-584
Mots-Clés Beta diversity; differentiation; freshwater fish; homogenization; macroecology; partitioning; turnover
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ISSN 1466-8238 ISBN Médium
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