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Auteur (down) Violle, C.; Thuiller, W.; Mouquet, N.; Munoz, F.; Kraft, N.J.B.; Cadotte, M.W.; Livingstone, S.W.; Mouillot, D.
Titre Functional Rarity: The Ecology of Outliers Type Article scientifique
Année 2017 Publication Revue Abrégée Trends Ecol. Evol.
Volume 32 Numéro 5 Pages 356-367
Mots-Clés biodiversity; community ecology; Conservation; ecosystem function; intraspecific variability; niche; phylogenetic diversity; plant-communities; spatial mismatch; trait
Résumé Rarity has been a central topic for conservation and evolutionary biologists aiming to determine the species characteristics that cause extinction risk. More recently, beyond the rarity of species, the rarity of functions or functional traits, called functional rarity, has gained momentum in helping to understand the impact of biodiversity decline on ecosystem functioning. However, a conceptual framework for defining and quantifying functional rarity is still lacking. We introduce 12 different forms of functional rarity along gradients of species scarcity and trait distinctiveness. We then highlight the potential key role of functional rarity in the long-term and large-scale maintenance of ecosystem processes, as well as the necessary linkage between functional and evolutionary rarity.
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ISSN 0169-5347 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2131
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Auteur (down) Villon, S.; Mouillot, D.; Chaumont, M.; Subsol, G.; Claverie, T.; Villeger, S.
Titre A new method to control error rates in automated species identification with deep learning algorithms Type Article scientifique
Année 2020 Publication Revue Abrégée Sci Rep
Volume 10 Numéro 1 Pages 10972
Mots-Clés aerial vehicles; biodiversity; reject
Résumé Processing data from surveys using photos or videos remains a major bottleneck in ecology. Deep Learning Algorithms (DLAs) have been increasingly used to automatically identify organisms on images. However, despite recent advances, it remains difficult to control the error rate of such methods. Here, we proposed a new framework to control the error rate of DLAs. More precisely, for each species, a confidence threshold was automatically computed using a training dataset independent from the one used to train the DLAs. These species-specific thresholds were then used to post-process the outputs of the DLAs, assigning classification scores to each class for a given image including a new class called “unsure”. We applied this framework to a study case identifying 20 fish species from 13,232 underwater images on coral reefs. The overall rate of species misclassification decreased from 22% with the raw DLAs to 2.98% after post-processing using the thresholds defined to minimize the risk of misclassification. This new framework has the potential to unclog the bottleneck of information extraction from massive digital data while ensuring a high level of accuracy in biodiversity assessment.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 2045-2322 ISBN Médium
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Notes WOS:000546533700003 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2861
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Auteur (down) Villeger, S.; Maire, Eva; Leprieur, F.
Titre On the risks of using dendrograms to measure functional diversity and multidimensional spaces to measure phylogenetic diversity: a comment on Sobral et al. (2016) Type Article scientifique
Année 2017 Publication Revue Abrégée Ecol. Lett.
Volume 20 Numéro 4 Pages 554-557
Mots-Clés assemblages; cophenetic distance; dendrogram; Euclidean space; functional diversity; functional space; phylogenetic diversity; reveals
Résumé Sobral et al. (Ecology Letters, 19, 2016, 1091) reported that the loss of bird functional and phylogenetic diversity due to species extinctions was not compensated by exotic species introductions. Here, we demonstrate that the reported changes in biodiversity were underestimated because of methodological pitfalls.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1461-023x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2116
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Auteur (down) 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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Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1466-8238 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1178
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Auteur (down) Villeger, S.; Grenouillet, G.; Brosse, S.
Titre Decomposing functional β-diversity reveals that low functional β-diversity is driven by low functional turnover in European fish assemblages Type Article scientifique
Année 2013 Publication Revue Abrégée Global Ecology and Biogeography
Volume 22 Numéro 6 Pages 671-681
Mots-Clés Europe; Functional richness; beta-diversity; convex hull volume; freshwater fish; functional diversity; functional traits; overlap
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Volume de collection Numéro de collection Edition
ISSN 1466-8238 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 507
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