Aurèle Toussaint

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Chargé de recherche (CR) / Researcher

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Centre de Recherche sur la Biodiversité et l'Environnement
UMR5300 — UPS · CNRS · IRD · INP
Université de Toulouse
Bât. 4R1, bureau 29
118 Route de Narbonne
31062 Toulouse, France
Website

Metrics

Full CV available here
ResearchGate
Google Scholar
ORCID: 0000-0002-5738-4637

Contact

aurele.toussaint@cnrs.fr
aurele.toussaint@utoulouse.fr

Research

My research sits at the interface of macroecology, functional ecology, and conservation biology, with a focus on understanding how the functional diversity of vertebrates and plants is distributed across the globe, what processes generate and maintain these patterns, and how anthropogenic pressures are reshaping them.

A central theme of my work is the functional diversity of freshwater fishes. During my PhD and subsequent projects, I built one of the largest morphological trait databases for freshwater fishes, covering more than 9,000 species across more than 1,000 river basins worldwide. This work revealed that functional diversity is highly concentrated in the Neotropics — which host more than 75% of global functional diversity — and is only weakly correlated with species richness at macroecological scales. I showed that the introduction of non-native species has fundamentally restructured the functional composition of fish assemblages worldwide, increasing functional diversity by up to 150% on average while simultaneously driving taxonomic homogenization through the dominance of a few widespread invasive species.

A second major axis of my research concerns the consequences of biodiversity loss for functional diversity. I have demonstrated that the extinction of threatened vertebrates will not lead to uniform losses of functional diversity, but rather to idiosyncratic changes that vary substantially across biogeographic realms and taxonomic groups. In birds, I showed that non-native species will not compensate for the functional and phylogenetic diversity lost following the extinction of threatened species, highlighting the irreplaceable role of native biodiversity in sustaining ecosystem functioning. This work contributed to a broader programme on the erosion of functional diversity across the tree of life, which demonstrated that extinction risk is non-randomly distributed in functional trait space and that threatened species disproportionately occupy unique functional positions.

More recently, I have been investigating intraspecific trait variability as a neglected but critical component of functional diversity. The INTRAIT project, supported by CEBA and TREMPLIN, aims to quantify morphological variation within freshwater fish species in French Guiana and to assess how ignoring this variability biases community-level estimates of functional diversity. This work bridges individual-level phenotypic variation and macroecological patterns, and is carried out in close collaboration with master and PhD students at CRBE.

Across all these research axes, I employ a combination of large-scale trait databases, multivariate statistics, and simulation approaches implemented in R. I am particularly interested in methodological questions surrounding the measurement and comparison of functional diversity indices, and in developing reproducible analytical pipelines for handling large biodiversity datasets. My work has been published in leading international journals including Nature, Nature Communications, Science Advances, Ecology Letters, and Global Ecology and Biogeography.

Word cloud of research themes

Current grants

2025–2026  |  INTRAIT — Influence of Intraspecific trait variability on the functional diversity of fish communities in French Guiana.
Supported by CEBA here and TREMPLIN here.

Previous grants

2020–2023  |  Research Fellow — Estonian Research Council (PSG-505). Details
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2017–2019  |  Post-doctoral Fellow — Estonian Research Council (MOBJD-276). Details
2016  |  Erasmus MUNDUS — Kyung Hee University, Seoul, Korea.

Publications

A full list is available on Google Scholar and ResearchGate. Data repository available here.

  1. 2025
  2. Partel M., Tamme R., …, Toussaint A., …, Zobel M. Global impoverishment of natural vegetation revealed by dark diversity. Nature, 641, 917–924. PDF · Press release CNRS · Actualité CRBE · EurekAlert
  3. Chen Z., Xu C., Brosse S., Toussaint A., Xu J., Su G. Global Patterns and Determinants of Multiple Facets of Freshwater Fishes Beta Diversity. Global Ecology and Biogeography. PDF
  4. 2024
  5. Toussaint A., Pärtel M., Carmona C.P. Contrasting impacts of non-native and threatened species on morphological, life-history, and phylogenetic diversity in bird assemblages. Ecology Letters, 27, e14373. PDF
  6. Tordoni E., Carmona C.P., Toussaint A., Tamme R., Pärtel M. Global patterns and determinants of multiple facets of plant diversity. Global Ecology and Biogeography, e13823. PDF
  7. Carmona C.P., Pärtel M., Tamme R., Toussaint A. OTSIMAS ELURIKKUSE MÕÕTMEID LOOMADE JA TAIMEDE SEAST, MAA ALT JA MAA PEALT. EESTI VABARIIGI PREEMIAD. PDF
  8. Coulon N., Pilet S., Lizé A., Lacoue-Labarthe T., Sturbois A., Toussaint A., Feunteun E., Carpentier A. Shark critical life stage vulnerability to monthly temperature variations under climate change. Marine Environmental Research, 198, 106531. PDF
  9. 2023
  10. Toussaint A., Pärtel M., Carmona C.P. Contrasting impacts of non-native and threatened species on morphological, life-history, and phylogenetic diversity in birds' assemblages. Authorea. PDF
  11. Coulon N., Lindegren M., Goberville E., Toussaint A., Receveur A., Auber A. Threatened fish species in the Northeast Atlantic are functionally rare. Global Ecology and Biogeography, 1–19. PDF
  12. Bueno C.G., Toussaint A., Träger S. et al. Reply to: The importance of trait selection in ecology. Nature, 618, E31–E34. PDF
  13. Toussaint A., Pärtel M., Carmona C.P. Non-native bird species will not compensate for the loss of phylogenetic and functional diversity after the extinction of threatened species. Authorea. PDF
  14. de Tombeur F., Raven J.A., Toussaint A., Lambers H., Cooke J., Hartley S.E., Johnson S.N., Coq S., Katz O., Schaller J., Violle C. Why do plants silicify? Trends in Ecology and Evolution, 38(3), 275–288. PDF
  15. 2022
  16. Auber A., Waldock C., Maire A., Goberville E., Albouy C., Algar A.C., McLean M., Brind'Amour A., Green A.L., Tupper M., Vigliola L., Kaschner K., Kesner-Reyes K., Beger M., Tjiputra J., Toussaint A., Violle C., Mouquet N., Thuiller W., Mouillot D. A functional vulnerability framework for biodiversity conservation. Nature Communications, 13, 4774. PDF
  17. Paganeli B., Toussaint A., Bueno C.G., Fujinuma J., Reier Ü., Pärtel M. Dark diversity at home describes the success of cross-continent tree invasions. Diversity and Distributions, 28(6), 1202–1213. PDF
  18. Su G., Tedesco P.A., Toussaint A., Villeger S., Brosse S. Contemporary environment and historical legacy explain functional diversity of freshwater fishes in the world rivers. Global Ecology and Biogeography, 31, 700–713. PDF
  19. 2021
  20. Carmona C.P., Tamme R., Pärtel M., de Bello F., Brosse S., Capdevila P., Gonzalez-M R., Gonzalez-Suarez M., Salguero-Gomez R., Vasquez-Valderrama M., Toussaint A. Erosion of global functional diversity across the tree of life. Science Advances, 7(13), eabf2675. PDF · Press release CNRS · EurekAlert!
  21. Tordoni E., Toussaint A., Pärtel M., Nogues-Bravo D., Carmona C.P. Combining taxonomic, phylogenetic and functional diversity reveals new global priority areas for tetrapod conservation. bioRxiv. doi: 10.1101/2021.07.01.450689
  22. Toussaint A., Brosse S., Bueno C.G., Pärtel M., Tamme S., Carmona C.P. Extinction of threatened vertebrates will lead to idiosyncratic changes in functional diversity across the world. Nature Communications, 12(1), 1–12. PDF
  23. Carmona C.P., Bueno C.G., Toussaint A., Träger S., Diaz S., Moora M., Munson D.A., Pärtel M., Zobel M., Tamme R. Fine-root traits in the global spectrum of plant form and function. Nature, 597(7878), 683–687. PDF
  24. Brosse S., Charpin N., Su G., Toussaint A., Herrera-R. G.A., Tedesco P.A., Villeger S. FISHMORPH: A global database on morphological traits of freshwater fishes. Global Ecology and Biogeography, 30(12), 2330–2336. PDF
  25. 2020
  26. Toussaint A., Bueno C.G., Davison J., Moora M., Tedersoo L., Zobel M., Opik M., Partel M. Asymmetric patterns of global diversity among plants and mycorrhizal fungi. Journal of Vegetation Science, 31(2), 355–366. PDF
  27. Derezal O., Mondy P.C., Dembski S., Kreutzenberger K., Reyjol Y., Chanderis A., Valette L., Brosse S., Toussaint A., Beillard J., Merg M.L., Usseglio-Polatera P. A diagnostic-based approach to assess specific risks of river degradation in a multiple pressure context: Insights from fish communities. Science of The Total Environment, 734, 139467. PDF
  28. Carmona C.P., Tamme R., Partel M., de Bello F., Brosse S., Capdevila P., Gonzalez-M R., Gonzalez-Suarez M., Salguero-Gomez R., Vasquez-Valderrama M., Toussaint A. Mapping extinction risk in the global functional spectra across the tree of life. bioRxiv. doi: 10.1101/2020.06.29.179143
  29. 2018
  30. Tedersoo L., Laanisto L., Rahimlou S., Toussaint A., Hallikma T., Pärtel M. Global database of plants with root-symbiotic nitrogen fixation: Nod DB. Journal of Vegetation Science, 29(3), 560–568. PDF
  31. Kuczynski L., Côte J., Toussaint A., Brosse S., Buisson L., Grenouillet G. Spatial mismatch in morphological, ecological and phylogenetic diversity in historical and contemporary European freshwater fish faunas. Ecography, 41, 1665–1674. PDF
  32. Toussaint A., Charpin N., Beauchard O., Grenouillet G., Oberdorff T., Tedesco P.A., Villéger S., Brosse S. Non-native species led to marked shifts in functional diversity of the world freshwater fish faunas. Ecology Letters, 21(11), 1649–1659. PDF · Press release CNRS · Press release IRD · Blog post · Supplementary
  33. 2016
  34. Toussaint A., Beauchard O., Oberdorff T., Brosse S., Villeger S. Worldwide freshwater fish homogenization is driven by a few widespread non-native species. Biological Invasions, 18, 1295–1304. PDF
  35. Toussaint A., Charpin N., Brosse S., Villéger S. Global functional diversity of freshwater fish is concentrated in the Neotropics. Scientific Reports, 6, 22125. PDF · Press release CNRS · Radio (France Inter, 11/04/2016) · Supplementary
  36. 2015
  37. Allard L., Toussaint A., Vigouroux R., Brosse S. Length-weight relationship of 58 fish species in streams of French Guiana. Journal of Applied Ichthyology, 31, 567–570. PDF
  38. 2014
  39. Toussaint A., Beauchard O., Oberdorff T., Brosse S., Villéger S. Historical assemblage distinctiveness and the introduction of widespread non-native species explain worldwide changes in freshwater fish taxonomic dissimilarity. Global Ecology and Biogeography, 23, 574–584. PDF · Press release CNRS · Supplementary 1 · Supplementary 2

Student supervision

  • Adrien Lagalle. Master. 2026. Comparaison des méthodes de mesure des traits fonctionnels des poissons d'eau douce.
  • Anouk Schneider. Master. 2026. Quantification du biais utilisateur dans la mesure des traits morphologiques des poissons d'eau douce.
  • Laura Boutic. Bachelor. 2026. Quantification du biais utilisateur dans la mesure des traits morphologiques des poissons d'eau douce.
  • Joseph Crochez. Bachelor. 2026. Quantification du biais utilisateur dans la mesure des traits morphologiques des poissons d'eau douce.
  • Pierre Bertrand. Master. 2026. Quantification de la diversité intraspécifique des poissons d'eau douce de Guyane française et impact sur les mesures de diversité fonctionnelle.
  • Nell Pause. Master. 2025. Disentangling morphological, life-history, and dietary predictors of extinction risk and population trends in birds.
  • Pierre Bouchet. PhD Student. 2024–2027. Diversité fonctionnelle des vertébrés et utilisation par l'homme : liens entre traits fonctionnels, utilisation anthropique et crise de biodiversité.
  • Adrien Solacroup. Master. 2014. Characterization of the morphological intra-specific variability in the French Guyana and European freshwater fish community.

Communication

2025

  • France 3 Occitanie. Article sur la 'diversité fantôme'. Link

Awards

2024

Estonian Research Award for research on the functional diversity of plants and vertebrates at global scale. Key publications: Science Advances and Nature Communications.

Conferences

  • 2024 — Annual meeting for macroecology of the Ecological Society of Germany, Austria and Switzerland, Marburg, Germany. Contrasting impacts of non-native and threatened species on morphological, life-history, and phylogenetic diversity in bird assemblages.
  • 2023 — 19th International Symposium on River and Lake Environment (ISRLE 19), China. Mapping extinction risk in the global functional spectra across the tree of life.
  • 2020 — Annual meeting for macroecology of the Ecological Society of Germany, Austria and Switzerland, Konstanz, Germany. Mapping extinction risk in the global functional spectra across the tree of life.
  • 2018 — Annual meeting for macroecology of the Ecological Society of Germany, Austria and Switzerland, Birmendorf, Switzerland. Global mismatch between the species richness of vascular plants and symbiosis fungi.
  • 2017 — 60th IAVS Annual Symposium, Palermo, Italy. Global mismatch between the species richness of vascular plants and symbiosis fungi across biogeographic realms.
  • 2016 — 7th EAFES International Congress, Daegu, South Korea. Functional diversity and vulnerability of freshwater fish at the global scale.
  • 2015 — 9th Symposium for European Freshwater Sciences, Geneva, Switzerland. Introductions of non-native freshwater fish affected differently the taxonomic and functional biodiversity facets.
  • 2015 — 7th Biennial Conference of the International Biogeography Society, Bayreuth, Germany. Functional diversity of the freshwater fish fauna. (poster)
  • 2013 — 8th Symposium for European Freshwater Sciences, Münster, Germany. Historical assemblage distinctiveness and the introduction of widespread non-native species explain worldwide changes in freshwater fish taxonomic dissimilarity.

PhD Thesis

During my PhD, I investigated the functional diversity of freshwater fishes at the world scale under the advisement of Pr. Sébastien Brosse and Dr. Sébastien Villéger.

Toussaint A. 2016. Diversité fonctionnelle des poissons d'eau douce à l'échelle mondiale : patrons, déterminants et impacts des activités humaines. Université de Toulouse. 223p. PDF (in French only)

Detailed thesis abstract

Biodiversity is often characterized only through its taxonomic facet, i.e. the number and list of species present in assemblages. However, recent studies show that biodiversity cannot be summarized by this facet alone, as it does not reflect the ecological characteristics of species. Several facets can describe biodiversity, including functional diversity, which considers the ecological traits of species and thus their role in ecosystem functioning. Yet, few studies have described this facet at large scales, its links with taxonomic diversity, or its responses to global change.

The objectives of this thesis were to (1) describe and understand the distribution of the functional diversity of freshwater fish assemblages at the global scale and (2) quantify the consequences of human activities on both taxonomic and functional biodiversity facets. To these ends, a morphological traits database was built for more than 9,000 freshwater fish species occurring in more than 1,000 river basins worldwide.

Results demonstrate that functional diversity is unequally distributed across the world and weakly related to taxonomic diversity at global scale. Species-rich Neotropical rivers host more than 75% of global functional diversity, whereas African or Asian rivers — also rich in species — host less than a quarter of world functional diversity. This pattern is explained by the functional uniqueness of certain Neotropical fish orders. The functional diversity of different biogeographic realms is also unequally vulnerable to extinction: Europe and North America could lose between 35% and 45% of their functional diversity, while the Neotropical realm appears less sensitive, with only 10% of its functional diversity supported by vulnerable species.

The introduction of non-native species has contributed to profoundly changing historical patterns of biodiversity, promoting taxonomic homogenization accompanied by a decrease in unique species in the poorest assemblages — largely driven by a few widely introduced non-native species. Non-native species have also contributed to increasing functional diversity of assemblages by 150% on average, up to seven times greater than the increase reported for taxonomic diversity (~20% on average). These results underscore the high sensitivity of functional diversity to changes in species composition and the need to account for it when assessing the impact of current and future human activities on freshwater biodiversity.