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Auteur Virgili, A.; Authier, M.; Boisseau, O.; Cañadas, A.; Claridge, D.; Cole, T.; Corkeron, P.; Dorémus, G.; David, L.; Di‐Méglio, N.; Dunn, C.; Dunn, T.E.; García‐Barón, I.; Laran, S.; Lauriano, G.; Lewis, M.; Louzao, M.; Mannocci, L.; Martínez‐Cedeira, J.; Palka, D.; Panigada, S.; Pettex, E.; Roberts, J.J.; Ruiz, L.; Saavedra, C.; Santos, M.B.; Canneyt, O.V.; Bonales, J.A.V.; Monestiez, P.; Ridoux, V. url  doi
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  Titre Combining multiple visual surveys to model the habitat of deep-diving cetaceans at the basin scale Type Article scientifique
  Année 2019 Publication Revue Abrégée Global Ecology and Biogeography  
  Volume (down) 28 Numéro 3 Pages 300-314  
  Mots-Clés beaked whales; data-assembling; deep-diving cetaceans; habitat modelling; kogiids; sperm whales  
  Résumé Aim Deep-diving cetaceans are oceanic species exposed to multiple anthropogenic pressures including high intensity underwater noise, and knowledge of their distribution is crucial to manage their conservation. Due to intrinsic low densities, wide distribution ranges and limited presence at the sea surface, these species are rarely sighted. Pooling data from multiple visual surveys sharing a common line-transect methodology can increase sightings but requires accounting for heterogeneity in protocols and platforms. Location North Atlantic Ocean and Mediterranean Sea. Time period 1998 to 2015. Major taxa Ziphiidae; Physeteriidae; Kogiidae. Methods About 1,240,000 km of pooled effort provided 630 sightings of ziphiids, 836 of physeteriids and 106 of kogiids. For each taxon, we built a hierarchical model to estimate the effective strip width depending on observation conditions and survey types. We then modelled relative densities in a generalized additive modelling framework. Geographical predictions were limited to interpolations identified with a gap analysis of environmental space coverage. Results Deeper areas of the North Atlantic gyre were mostly environmental extrapolation in the predictions, thereby highlighting gaps in sampling across the different surveys. For the three species groups, the highest relative densities were predicted along continental slopes, particularly in the western North Atlantic Ocean where the Gulf Stream creates dynamic frontal zones and eddies. Main conclusions Pooling a large number of surveys provided the first basin-wide models of distribution for deep-diving cetaceans, including several data-deficient taxa, across the North Atlantic Ocean and the Mediterranean Sea. These models can help the conservation of elusive and poorly known marine megafauna.  
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  ISSN 1466-8238 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2756  
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Auteur Boyd, C.; Grunbaum, D.; Hunt, G.L.; Punt, A.E.; Weimerskirch, H.; Bertrand, S. doi  openurl
  Titre Effectiveness of social information used by seabirds searching for unpredictable and ephemeral prey Type Article scientifique
  Année 2016 Publication Revue Abrégée Behav. Ecol.  
  Volume (down) 27 Numéro 4 Pages 1223-1234  
  Mots-Clés agent-based model; albatrosses; antarctic krill; central place foragers; colonies; evolution; foraging model; gannets; Habitat selection; insights; local enhancement; local enhancement; models; public information; search strategies  
  Résumé Understanding how seabirds and other central place foragers locate food resources represents a key step in predicting responses to changes in resource abundance and distribution. Where prey distributions are unpredictable and ephemeral, seabirds may gain up-to-date information by monitoring the direction of birds returning to the colony or by monitoring the foraging behavior of other birds through local enhancement. However, search strategies based on social information may require high population densities, raising concerns about the potential loss of information in declining populations. Our objectives were to explore the mechanisms that underpin effective search strategies based on social information under a range of population densities and different foraging conditions. Testing relevant hypotheses through field observation is challenging because of limitations in the ability to manipulate population densities and foraging conditions. We therefore developed a spatially explicit individual-based foraging model, informed by data on the movement and foraging patterns of seabirds foraging on pelagic prey, and used model simulations to investigate the mechanisms underpinning search strategies. Orientation of outbound headings in line with returning birds enables departing birds to avoid areas without prey even at relatively low population densities. The mechanisms underpinning local enhancement are more effective as population densities increase and may be facilitated by other mechanisms that concentrate individuals in profitable areas. For seabirds and other central place foragers foraging on unpredictable and ephemeral food resources, information is especially valuable when resources are spatially concentrated and may play an important role in mitigating poor foraging conditions.  
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  ISSN 1045-2249 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2068  
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Auteur Matthews, T.J.; Triantis, K.A.; Rigal, F.; Borregaard, M.K.; Guilhaumon, F.; Whittaker, R.J. url  doi
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  Titre Island species–area relationships and species accumulation curves are not equivalent: an analysis of habitat island datasets Type Article scientifique
  Année 2016 Publication Revue Abrégée Global Ecology and Biogeography  
  Volume (down) 25 Numéro 5 Pages 607-618  
  Mots-Clés Boosted regression trees; conservation biogeography; fragmentation; habitat islands; island biogeography; island species–area relationship; macroecology; nestedness; species accumulation curve; species–area relationship  
  Résumé Aim The relationship between species number and area is of fundamental importance in macroecology and conservation science, yet the implications of different means of quantitative depiction of the relationship remain contentious. We set out (1) to establish the variation in form of the relationship between two distinct methods applied to the same habitat island datasets, (2) to explore the relevance of several key dataset properties for variation in the parameters of these relationships, and (3) to assess the implications for application of the resulting models. Locations Global. Methods Through literature search we compiled 97 habitat island datasets. For each we analysed the form of the island species–area relationship (ISAR) and several versions of species accumulation curve (SAC), giving priority to a randomized form (Ran-SAC). Having established the validity of the power model, we compared the slopes (z-values) between the ISAR and the SAC for each dataset. We used boosted regression tree and simulation analyses to investigate the effect of nestedness and other variables in driving observed differences in z-values between ISARs and SACs. Results The Ran-SAC was steeper than the ISAR in 77% of datasets. The differences were primarily driven by the degree of nestedness, although other variables (e.g. the number of islands in a dataset) were also important. The ISAR was often a poor predictor of archipelago species richness. Main conclusions Slopes of the ISAR and SAC for the same data set can vary substantially, revealing their non-equivalence, with implications for applications of species–area curve parameters in conservation science. For example, the ISAR was a poor predictor of archipelagic richness in datasets with a low degree of nestedness. Caution should be employed when using the ISAR for the purposes of extrapolation and prediction in habitat island systems.  
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Auteur Mante, C.; Kide, S.O.; Yao-Lafourcade, A.-F.; Mérigot, B. doi  openurl
  Titre Fitting the truncated negative binomial distribution to count data A comparison of estimators, with an application to groundfishes from the Mauritanian Exclusive Economic Zone Type Article scientifique
  Année 2016 Publication Revue Abrégée Environ. Ecol. Stat.  
  Volume (down) 23 Numéro 3 Pages 359-385  
  Mots-Clés Birth-and-dead models; classification; curves; diversity; habitat; Log-series; Minimum Hellinger distance; Negative binomial; parametric models; population; series; Species abundance; species abundance distributions; zeros  
  Résumé Modeling empirical distributions of repeated counts with parametric probability distributions is a frequent problem when studying species abundance. One must choose a family of distributions which is flexible enough to take into account very diverse patterns and possess parameters with clear biological/ecological interpretations. The negative binomial distribution fulfills these criteria and was selected for modeling counts of marine fish and invertebrates. This distribution depends on a vector of parameters, and ranges from the Poisson distribution (when ) to Fisher's log-series, when . Moreover, these parameters have biological/ecological interpretations which are detailed in the literature and in this study. We compared three estimators of K, and the parameter of Fisher's log-series, following the work of Rao CR (Statistical ecology. Pennsylvania State University Press, University Park, 1971) on a three-parameter unstandardized variant of the negative binomial distribution. We further investigated the coherence underlying parameter values resulting from the different estimators, using both real count data collected in the Mauritanian Exclusive Economic Zone (MEEZ) during the period 1987-2010 and realistic simulations of these data. In the case of the MEEZ, we first built homogeneous lists of counts (replicates), by gathering observations of each species with respect to “typical environments” obtained by clustering the sampled stations. The best estimation of was generally obtained by penalized minimum Hellinger distance estimation. Interestingly, the parameters of most of the correctly sampled species seem compatible with the classical birth-and-dead model of population growth with immigration by Kendall (Biometrika 35:6-15, 1948).  
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  ISSN 1352-8505 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2067  
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Auteur Hattab, T.; Albouy, C.; Lasram, F.B.R.; Somot, S.; Le Loc'h, F.; Leprieur, F. url  doi
openurl 
  Titre Towards a better understanding of potential impacts of climate change on marine species distribution: a multiscale modelling approach Type Article scientifique
  Année 2014 Publication Revue Abrégée Global Ecology and Biogeography  
  Volume (down) 23 Numéro 12 Pages 1417-1429  
  Mots-Clés climate change; exploited species; habitat loss; hierarchical filtering; Mediterranean Sea; spatial scale; species distribution modelling  
  Résumé Aim In this paper, we applied the concept of ‘hierarchical filters’ in community ecology to model marine species distribution at nested spatial scales. Location Global, Mediterranean Sea and the Gulf of Gabes (Tunisia). Methods We combined the predictions of bioclimatic envelope models (BEMs) and habitat models to assess the current distribution of 20 exploited marine species in the Gulf of Gabes. BEMs were first built at a global extent to account for the full range of climatic conditions encountered by a given species. Habitat models were then built using fine-grained habitat variables at the scale of the Gulf of Gabes. We also used this hierarchical filtering approach to project the future distribution of these species under both climate change (the A2 scenario implemented with the Mediterranean climatic model NEMOMED8) and habitat loss (the loss of Posidonia oceanica meadows) scenarios. Results The hierarchical filtering approach predicted current species geographical ranges to be on average 56% smaller than those predicted using the BEMs alone. This pattern was also observed under the climate change scenario. Combining the habitat loss and climate change scenarios indicated that the magnitude of range shifts due to climate change was larger than from the loss of P. oceanica meadows. Main conclusions Our findings emphasize that BEMs may overestimate current and future ranges of marine species if species–habitat relationships are not also considered. A hierarchical filtering approach that accounts for fine-grained habitat variables limits the uncertainty associated with model-based recommendations, thus ensuring their outputs remain applicable within the context of marine resource management.  
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  Numéro d'Appel LL @ pixluser @ collection 391  
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