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Auteur (up) Almoussawi, A.; Lenoir, J.; Jamoneau, A.; Hattab, T.; Wasof, S.; Gallet-Moron, E.; Garzon-Lopez, C.X.; Spicher, F.; Kobaissi, A.; Decocq, G. doi  openurl
  Titre Forest fragmentation shapes the alpha-gamma relationship in plant diversity Type Article scientifique
  Année 2019 Publication Revue Abrégée J. Veg. Sci.  
  Volume Numéro Pages  
  Mots-Clés agricultural landscapes; alpha diversity; anthropogenic disturbances; assemblages; community assembly; community patterns; competition; connectivity; dispersal limitations; gamma diversity; habitat conservation strategies; habitat fragmentation; local-regional richness relationship; metacommunity dynamics; regional species richness; relative importance; saturation; specialists; succession  
  Résumé Questions Forest fragmentation affects biodiversity locally (alpha diversity) and beyond – at relatively larger scales (gamma diversity) – by increasing dispersal and recruitment limitations. Yet, does an increase in fragmentation affect the relationship between alpha and gamma diversity and what can we learn from it? Location Northern France. Methods We surveyed 116 forest patches across three fragmentation levels: none (continuous forest); intermediate (forest patches connected by hedgerows); and high (isolated forest patches). Plant species richness of both forest specialists and generalists was surveyed at five nested spatial resolutions across each forest patch: 1 m(2); 10 m(2); 100 m(2); 1,000 m(2); and total forest patch area. First, we ran log-ratio models to quantify the alpha-gamma relationship. We did that separately for all possible combinations of fragmentation level (none vs intermediate vs high) x spatial scale (e.g., alpha-1 m(2) vs gamma-10 m(2)) x species type (e.g., alpha-specialists vs gamma-specialists). We then used linear mixed-effects models to analyze the effect of fragmentation level, spatial scale, species type and all two-way interaction terms on the slope coefficient extracted from all log-ratio models. Results We found an interaction effect between fragmentation level and species type, such that forest specialists shifted from a linear (i.e., proportional sampling) to a curvilinear plateau (i.e., community saturation) relationship at low and high fragmentation, respectively, while generalists shifted from a curvilinear to a linear pattern. Conclusions The impact of forest fragmentation on the alpha-gamma relationship supports generalist species persistence over forest specialists, with contrasting mechanisms for these two guilds. As fragmentation increases, forest specialists shift from proportional sampling towards community saturation, thus reducing alpha diversity likely due to dispersal limitation. Contrariwise, generalists shift from community saturation towards proportional sampling, thus increasing alpha diversity likely due to an increase in the edge:core ratio. To ensure long-term conservation of forest specialists, one single large forest patch should be preferred over several small ones.  
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  ISSN 1100-9233 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2676  
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Auteur (up) Andrello, M.; Guilhaumon, F.; Albouy, C.; Parravicini, V.; Scholtens, J.; Verley, P.; Barange, M.; Sumaila, U.R.; Manel, S.; Mouillot, D. doi  openurl
  Titre Global mismatch between fishing dependency and larval supply from marine reserves Type Article scientifique
  Année 2017 Publication Revue Abrégée Nat. Commun.  
  Volume 8 Numéro Pages 16039  
  Mots-Clés biodiversity conservation; climate-change; Connectivity; dispersal; fisheries management; impacts; Populations; protected areas; reef fishes; world  
  Résumé Marine reserves are viewed as flagship tools to protect exploited species and to contribute to the effective management of coastal fisheries. Yet, the extent to which marine reserves are globally interconnected and able to effectively seed areas, where fisheries are most critical for food and livelihood security is largely unknown. Using a hydrodynamic model of larval dispersal, we predict that most marine reserves are not interconnected by currents and that their potential benefits to fishing areas are presently limited, since countries with high dependency on coastal fisheries receive very little larval supply from marine reserves. This global mismatch could be reversed, however, by placing new marine reserves in areas sufficiently remote to minimize social and economic costs but sufficiently connected through sea currents to seed the most exploited fisheries and endangered ecosystems.  
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  Volume de collection Numéro de collection Edition  
  ISSN 2041-1723 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2162  
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Auteur (up) Briscoe, D.K.; Hobday, A.J.; Carlisle, A.; Scales, K.; Eveson, J.P.; Arrizabalaga, H.; Druon, J.N.; Fromentin, J.-M. doi  openurl
  Titre Ecological bridges and barriers in pelagic ecosystems Type Article scientifique
  Année 2017 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 140 Numéro Pages 182-192  
  Mots-Clés arctic marine mammals; atlantic bluefin tuna; Billfish; Brazilian episode; climate-change; el-nino; interannual variation; Marine mammal; marlin makaira-nigricans; Migration corridors; Oceanographic features; population connectivity; satellite archival tags; sea-turtles; site fidelity; species distribution; thunnus-maccoyii; Tuna  
  Résumé Many highly mobile species are known to use persistent pathways or corridors to move between habitat patches in which conditions are favorable for particular activities, such as breeding or foraging. In the marine realm, environmental variability can lead to the development of temporary periods of anomalous oceanographic conditions that can connect individuals to areas of habitat outside a population's usual range, or alternatively, restrict individuals from areas usually within their range, thus acting as ecological bridges or ecological barriers. These temporary features can result in novel or irregular trophic interactions and changes in population spatial dynamics, and, therefore, may have significant implications for management of marine ecosystems. Here, we provide evidence of ecological bridges and barriers in different ocean regions, drawing upon five case studies in which particular oceanographic conditions have facilitated or restricted the movements of individuals from highly migratory species. We discuss the potential population-level significance of ecological bridges and barriers, with respect to the life history characteristics of different species, and inter- and intra-population variability in habitat use. Finally, we summarize the persistence of bridge dynamics with time, our ability to monitor bridges and barriers in a changing climate, and implications for forecasting future climate mediated ecosystem change.  
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  ISSN 0967-0645 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2178  
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Auteur (up) Cahill, A.E.; De Jode, A.; Dubois, S.; Bouzaza, Z.; Aurelle, D.; Boissin, E.; Chabrol, O.; David, R.; Egea, E.; Ledoux, J.-B.; Mérigot, B.; Weber, A.A.-T.; Chenuil, A. doi  openurl
  Titre A multispecies approach reveals hot spots and cold spots of diversity and connectivity in invertebrate species with contrasting dispersal modes Type Article scientifique
  Année 2017 Publication Revue Abrégée Mol. Ecol.  
  Volume 26 Numéro 23 Pages 6563-6577  
  Mots-Clés genetic diversity; dispersal; life-history traits; reef fishes; marine connectivity; pelagic larval duration; mediterranean sea; amphipholis-squamata; brooding brittle star; coralligenous assemblages; larvae; marine invertebrates; phylogeographical breaks; population structure; population genetic-structure; species genetic diversity correlation  
  Résumé Genetic diversity is crucial for species' maintenance and persistence, yet is often overlooked in conservation studies. Species diversity is more often reported due to practical constraints, but it is unknown if these measures of diversity are correlated. In marine invertebrates, adults are often sessile or sedentary and populations exchange genes via dispersal of gametes and larvae. Species with a larval period are expected to have more connected populations than those without larval dispersal. We assessed the relationship between measures of species and genetic diversity, and between dispersal ability and connectivity. We compiled data on genetic patterns and life history traits in nine species across five phyla. Sampling sites spanned 600km in the northwest Mediterranean Sea and focused on a 50-km area near Marseilles, France. Comparative population genetic approaches yielded three main results. (i) Species without larvae showed higher levels of genetic structure than species with free-living larvae, but the role of larval type (lecithotrophic or planktotrophic) was negligible. (ii) A narrow area around Marseilles, subject to offshore advection, limited genetic connectivity in most species. (iii) We identified sites with significant positive contributions to overall genetic diversity across all species, corresponding with areas near low human population densities. In contrast, high levels of human activity corresponded with a negative contribution to overall genetic diversity. Genetic diversity within species was positively and significantly linearly related to local species diversity. Our study suggests that local contribution to overall genetic diversity should be taken into account for future conservation strategies.  
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  Volume de collection Numéro de collection Edition  
  ISSN 0962-1083 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2262  
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Auteur (up) Calo, A.; Lett, C.; Mourre, B.; Perez-Ruzafa, A.; Antonio Garcia-Charton, J. doi  openurl
  Titre Use of Lagrangian simulations to hindcast the geographical position of propagule release zones in a Mediterranean coastal fish Type Article scientifique
  Année 2018 Publication Revue Abrégée Mar. Environ. Res.  
  Volume 134 Numéro Pages 16-27  
  Mots-Clés circulation; Mediterranean Sea; sea; dispersal; larval; habitat; marine protected areas; recruitment; variability; population connectivity; Dispersal distance; Lagrangian simulations; mesoscale eddies; Propagule release zones; Sea bream  
  Résumé The study of organism dispersal is fundamental for elucidating patterns of connectivity between populations, thus crucial for the design of effective protection and management strategies. This is especially challenging in the case of coastal fish, for which information on egg release zones (i.e. spawning grounds) is often lacking. Here we assessed the putative location of egg release zones of the saddled sea bream (Oblada melanura) along the southeastern coast of Spain in 2013. To this aim, we hindcasted propagule (egg and larva) dispersal using Lagrangian simulations, fed with species-specific information on early life history traits (ELTs), with two approaches: 1) back-tracking and 2) comparing settler distribution obtained from simulations to the analogous distribution resulting from otolith chemical analysis. Simulations were also used to assess which factors contributed the most to dispersal distances. Back-tracking simulations indicated that both the northern sector of the Murcia region and some traits of the North-African coast were hydrodynamically suitable to generate and drive the supply of larvae recorded along the coast of Murcia in 2013. With the second approach, based on the correlation between simulation outputs and field results (otolith chemical analysis), we found that the oceanographic characteristics of the study area could have determined the pattern of settler distribution recorded with otolith analysis in 2013 and inferred the geographical position of main O. melanura spawning grounds along the coast. Dispersal distance was found to be significantly affected by the geographical position of propagule release zones. The combination of methods used was the first attempt to assess the geographical position of propagule release zones in the Mediterranean Sea for O. melanura, and can represent a valuable approach for elucidating dispersal and connectivity patterns in other coastal species.  
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  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0141-1136 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2313  
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