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Auteur Fablet, R.; Chaigneau, A.; Bertrand, S. url  doi
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  Titre Multiscale analysis of geometric planar deformations : application to wild animal electronic tracking and satellite ocean observation data Type Article scientifique
  Année 2014 Publication Revue Abrégée Ieee Transactions on Geoscience and Remote Sensing  
  Volume 52 Numéro 6 Pages 3627-3636  
  Mots-Clés Animal movements; geophysical fields; multiscale geometry; planar curve; trajectory analysis; wavelet analysis  
  Résumé The development of animal tracking technologies (including GPS and ARGOS satellite systems) and the increasing resolution of remote-sensing observations call for tools extracting and describing the geometric patterns along a track or within an image over a wide range of spatial scales. Whereas shape analysis has largely been addressed over the last decades, the multiscale analysis of the geometry of opened planar curves has received little attention. We here show that classical multiscale techniques cannot properly address this issue and propose an original wavelet-based scheme. To highlight the generic nature of our multiscale wavelet technique, we report applications to two different observation data sets, namely, wild animal movement paths recorded by electronic tags and satellite observations of sea-surface geophysical fields.  
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  ISSN 0196-2892 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 328  
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Auteur Courbin, N.; Besnard, A.; Peron, C.; Saraux, C.; Fort, J.; Perret, S.; Tornos, J.; Gremillet, D. doi  openurl
  Titre Short-term prey field lability constrains individual specialisation in resource selection and foraging site fidelity in a marine predator Type Article scientifique
  Année 2018 Publication Revue Abrégée Ecol. Lett.  
  Volume 21 Numéro 7 Pages 1043-1054  
  Mots-Clés behavior; Behavioural consistency; Calonectris diomedea; diet; ecology; foraging site fidelity; gannets; habitat selection; mediterranean sea; models; movement; resource selection; Scopoli's shearwater; seabirds; strategies; temporal resource dynamic; Western Mediterranean  
  Résumé Spatio-temporally stable prey distributions coupled with individual foraging site fidelity are predicted to favour individual resource specialisation. Conversely, predators coping with dynamic prey distributions should diversify their individual diet and/or shift foraging areas to increase net intake. We studied individual specialisation in Scopoli's shearwaters (Calonectris diomedea) from the highly dynamic Western Mediterranean, using daily prey distributions together with resource selection, site fidelity and trophic-level analyses. As hypothesised, we found dietary diversification, low foraging site fidelity and almost no individual specialisation in resource selection. Crucially, shearwaters switched daily foraging tactics, selecting areas with contrasting prey of varying trophic levels. Overall, information use and plastic resource selection of individuals with reduced short-term foraging site fidelity allow predators to overcome prey field lability. Our study is an essential step towards a better understanding of individual responses to enhanced environmental stochasticity driven by global changes, and of pathways favouring population persistence.  
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  ISSN 1461-023x ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2380  
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Auteur Carpentier, A.S.; Berthe, C.; Ender, I.; Jaine, F.R.A.; Mourier, J.; Stevens, G.; De Rosemont, M.; Clua, E. doi  openurl
  Titre Preliminary insights into the population characteristics and distribution of reef (Mobula alfredi) and oceanic (M. birostris) manta rays in French Polynesia Type Article scientifique
  Année 2019 Publication Revue Abrégée Coral Reefs  
  Volume 38 Numéro 6 Pages 1197-1210  
  Mots-Clés aggregation; australia; bottle-nosed dolphins; california; Citizen science; conservation; Ecotourism management; habitat use; identification; marine park; movements; sharks; Site fidelity; Spatial connectivity; Sympatry  
  Résumé In French Polynesia, both currently recognized manta ray species, Mobula alfredi and M. birostris, are observed. Despite being an important cultural asset and generating significant economic benefits through manta ray watching tourism, published data on the ecology and threats to these species in the region are scarce. Based on an 18-year dataset of sighting records collected by citizen scientists and during two scientific expeditions, this study provides the first insights into the population characteristics and regional distribution of the two manta ray species in French Polynesia. A total of 1347 manta ray photographs (1337 for M. alfredi and 10 for M. birostris) were examined for the period January 2001-December 2017, with photo-identification techniques leading to the successful identification of 317 individual M. alfredi and 10 individual M. birostris throughout the Society, Tuamotu and Marquesas Islands. We provide the first confirmation of sympatric distribution of both species in the Society Islands. Our results highlight strong and long-term site fidelity of M. alfredi individuals to certain aggregation sites (> 9 years for 16 individuals) and reveal some degree of connectivity between populations, with 10 individuals recorded moving between islands located up to 50 km apart. Analysis of photographs of individuals bearing sub-lethal injuries (n = 68) suggests that M. alfredi are more likely to be injured at inhabited islands (Maupiti or Bora Bora; 75% of all injured individuals) than at uninhabited islands, with 75% of injuries related to boat propeller strikes and fishing gear entanglements. Our findings emphasize the need for further research to allow for a comprehensive evaluation of population structure, size and threats to manta rays in this region.  
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  ISSN 0722-4028 ISBN Médium  
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  Notes WOS:000496024100010 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2658  
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Auteur Boyd, C.; Punt, A.E.; Weimerskirch, H.; Bertrand, S. url  doi
openurl 
  Titre Movement models provide insights into variation in the foraging effort of central place foragers Type Article scientifique
  Année 2014 Publication Revue Abrégée Ecological Modelling  
  Volume 286 Numéro Pages 13-25  
  Mots-Clés Animal movement; Foraging ecology; Hidden Markov model; Provisioning theory; Seabirds; Sula variegata  
  Résumé Ecology and conservation depend on an understanding of how animals adjust their behaviour patterns in response to changes in their environment. Central place foragers (CPFs) are well-suited for developing ecological models of adaptive processes because their objective functions and operational constraints can be reasonably inferred. Central place foraging and provisioning theory provide the theoretical framework for this analysis. Analysis of CPF time allocation and energy budgets can provide insights into their strategies for responding to environmental variation. However, until recently, suitable high-resolution data on the behaviour of seabirds and other CPFs at sea have not been available. Previous studies of breeding seabirds have investigated variation in foraging trip duration and colony attendance, but few studies have analyzed variation in time allocation within foraging trips. Here, we develop a conceptual energy-based model for analysing variation in the time allocation of CPFs during foraging trips, and apply it to the movement patterns of Peruvian boobies (Sula variegata). Foraging trips of Peruvian boobies, recorded using high-resolution global positioning systems (GPS), were first partitioned into movement modes consistent with travel and foraging behaviours using a hidden Markov model (HMM) adapted to account for gaps in the GPS tracks associated with diving behaviour. Analysis of the HMM results based on the conceptual model indicated that differences in foraging effort between two treatments were best explained by a combination of differences in travel time and in time spent searching for prey. The conceptual model provides the basis for an integrated approach to analysis of variation in foraging strategies in which identification of various behaviours is coupled with assessments of time and energy budgets. This integrated approach can contribute to greater understanding of the processes determining foraging strategies and the limits to these strategies in the context of competition for resources and global climate change.  
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  ISSN 0304-3800 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 355  
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Auteur van Gils, J.A.; van der Geest, M.; De Meulenaer, B.; Gillis, H.; Piersma, T.; Folmer, E.O. url  doi
openurl 
  Titre Moving on with foraging theory: incorporating movement decisions into the functional response of a gregarious shorebird Type Article scientifique
  Année 2015 Publication Revue Abrégée Journal of Animal Ecology  
  Volume 84 Numéro Pages 554-564  
  Mots-Clés competition continuous-time Markov chain cryptic interference diet distribution habitat choice intake rate movement ecology predation toxic prey SPATIAL-DISTRIBUTION RED KNOTS MODELING INTERFERENCE CRYPTIC INTERFERENCE STOCHASTIC VERSION BEHAVIORAL ECOLOGY MULTISTATE MODELS BANC-DARGUIN GROUP-SIZE PREY Ecology Zoology  
  Résumé 1. Models relating intake rate to food abundance and competitor density (generalized functional response models) can predict forager distributions and movements between patches, but we lack understanding of how distributions and small-scale movements by the foragers themselves affect intake rates. Using a state-of-the-art approach based on continuous-time Markov chain dynamics, we add realism to classic functional response models by acknowledging that the chances to encounter food and competitors are influenced by movement decisions, and, vice versa, that movement decisions are influenced by these encounters. We used a multi-state modelling framework to construct a stochastic functional response model in which foragers alternate between three behavioural states: searching, handling and moving. Using behavioural observations on a molluscivore migrant shorebird (red knot, Calidris canutus canutus), at its main wintering area (Banc d'Arguin, Mauritania), we estimated transition rates between foraging states as a function of conspecific densities and densities of the two main bivalve prey. Intake rate decreased with conspecific density. This interference effect was not due to decreased searching efficiency, but resulted from time lost to avoidance movements. Red knots showed a strong functional response to one prey (Dosinia isocardia), but a weak response to the other prey (Loripes lucinalis). This corroborates predictions from a recently developed optimal diet model that accounts for the mildly toxic effects due to consuming Loripes. Using model averaging across the most plausible multi-state models, the fully parameterized functional response model was then used to predict intake rate for an independent data set on habitat choice by red knot. Comparison of the sites selected by red knots with random sampling sites showed that the birds fed at sites with higher than average Loripes and Dosinia densities, that is sites for which we predicted higher than average intake rates. We discuss the limitations of Holling's classic functional response model which ignores movement and the limitations of contemporary movement ecological theory that ignores consumer-resource interactions. With the rapid advancement of technologies to track movements of individual foragers at fine spatial scales, the time is ripe to integrate descriptive tracking studies with stochastic movement-based functional response models.  
  Adresse [van Gils, Jan A.; van der Geest, Matthijs; De Meulenaer, Brecht; Gillis, Hanneke; Piersma, Theunis; Folmer, Eelke O.] NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, NL-1790 AB Den Burg, Texel, Netherlands. [van der Geest, Matthijs; Piersma, Theunis] Univ Groningen, Anim Ecol Grp, Ctr Ecol & Evolutionary Studies CEES, Chair Global Flyway Ecol, NL-9700 CC Groningen, Netherlands. van Gils, JA (reprint author), NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, POB 59, NL-1790 AB Den Burg, Texel, Netherlands. Jan.van.Gils@nioz.nl  
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  Langue English Langue du Résumé Titre Original  
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  ISSN 0021-8790 ISBN Médium  
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  Notes ISI Document Delivery No.: CB9RB Times Cited: 0 Cited Reference Count: 61 van Gils, Jan A. van der Geest, Matthijs De Meulenaer, Brecht Gillis, Hanneke Piersma, Theunis Folmer, Eelke O. NWO WOTRO [W.01.65.221.00]; NWO [R 84-639]; NWO VIDI [864.09.002] We thank Parc National du Banc d'Arguin (PNBA) for their hospitality, the hosting of our presence and the permission to work in and from the Iwik scientific station. Lemhaba ould Yarba made the logistic arrangements. Joop van Eerbeek, Erik J. Jansen, Han Olff and El-Hacen Mohamed El-Hacen helped collecting and sorting benthos samples. Valuable comments on the manuscript were given by Allert Bijleveld, Jaap van der Meer, Ola Olsson, Thomas Oudman, Isabel M. Smallegange, an anonymous referee and by the 'literature club' of the Centre for Integrative Ecology during JAvG's sabbatical at Deakin University. Dick Visser polished the figures. This work is supported by an NWO WOTRO Integrated Programme grant (W.01.65.221.00) to TP, an NWO travel grant (R 84-639) to EOF, and an NWO VIDI grant (864.09.002) to JAvG. 0 WILEY-BLACKWELL HOBOKEN J ANIM ECOL Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ 1412 collection 1383  
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