M2 internship: Long-term changes in taxonomic and functional diversity of aquatic communities in large French

One internship position focusing on the taxonomic diversity and functional trait diversity in French river ecological communities is available at the RECOVER laboratory in Aix-En-Provence (France). The student will work under the supervision of Juliette VALLIN and Arnaud SENTIS.

Topic:
Climate change is causing an increase of the mean global temperature and of the intensity and frequency of extreme events. This can strongly impact organisms depending on their physiological and functional traits. Some species can benefit from increased temperature and increase their growth and abundances, while others will be negatively impacted. When negatively impacted by warm temperatures, species can resist or migrate to cooler environments if possible. If none of those strategies are possible, the fitness and survival of species will decline, sometimes leading to the extinction of whole populations. This can lead to vast turnover in taxonomic and functional composition of natural communities, with immediate consequences for ecosystem stability and functioning, and thus ecosystem services.
Studying biodiversity trends in the long term is crucial to understand the impacts of climate change on biodiversity and to forecast future evolution of life on earth under climate change. Moreover, it is crucial to identify species that are at higher risk of extinction under climate change, and functional traits that make species sensitive to temperature changes, to set up appropriate management and conservation measures.
Freshwater organisms are of particular concern, because they are mainly composed of ectotherms, that are dependent on ambient temperature to regulate their body temperature.
This project aims at understanding how freshwater biodiversity have changed in large French rivers over the past few decades, and how these temporal dynamics had impacted the composition in functional traits.

Objectives:
The aim of the internship is to (1) gather functional trait data (e.g. life organisms size, trophic level, upper thermal limit) for a list of fish species and macroinvertebrate families, to (2) study and compare the taxonomic structure and temporal dynamics of aquatic communities in two large French rivers (the Loire and Rhône rivers), to (3) study the functional trait structure and temporal dynamics in those same sites and compare them between sites, and to (4) conclude about the sensitivity to environmental changes (in particular to climate change) of the studied species in the light of their dynamics and functional traits.

Methods and data:
Long term monitoring time series have already been assembled, with one study site on the Loire River (25 years of data available) and one study site on the Rhône River (42 years of data available), in France. Each site is made up of several sampling stations. Data include fish and macroinvertebrate time series at community level. The internship consists in gathering (from scientific literature and available trait databases) functional traits for all fish species and macroinvertebrate families present in the dataset, and to investigate the above-mentioned objectives with diverse statistical methods like linear models, temporal trend and multivariate analyses.
Key-words: rivers, communities, temporal dynamics, functional traits, fish, macroinvertebrate, climate change

Candidate competences:
We are seeking a highly motivated student with good organizational skills and interests in river ecology, temporal ecology, functional ecology or statistics. Master students (preferably 2nd year master students or equivalent) in ecology, applied mathematics, natural-system modeling or a related field are welcomed. Knowledge of an analytical language like R is essential and a previous experience with data analysis would be highly appreciated.
To apply (before the 15th of November), please send your CV and motivation letter (1 page maximum in French or English) to Juliette Vallin (juliette.vallin@inrae.fr) and Arnaud Sentis (arnaud.sentis@inrae.fr). Informal enquiries are welcome – please contact us by email in French or English.

Practical information:
Starting date (flexible): January to March 2025
Duration: 6 months
Main advisors: Juliette Vallin and Arnaud Sentis
Location: INRAE, 3275 route Cézanne, 13182 Aix-en-Provence, France

References

Maire, A., Thierry, E., Viechtbauer, W., & Daufresne, M. (2019). Poleward shift in large-river fish communities detected with a novel meta-analysis framework. Freshwater Biology, 64(6), 1143 1156. https://doi.org/10.1111/fwb.13291

Daufresne, M., Roger, M. C., Capra, H., & Lamouroux, N. (2004). Long-term changes within the invertebrate and fish communities of the Upper Rhône River : Effects of climatic factors. Global Change Biology, 10(1), 124 140. https://doi.org/10.1046/j.1529-8817.2003.00720.x

Daufresne, M., Bady, P., & Fruget, J.-F. (2007). Impacts of global changes and extreme hydroclimatic events on macroinvertebrate community structures in the French Rhône River. Oecologia, 151(3), 544 559. https://doi.org/10.1007/s00442-006-0655-1

Bruno, D., Belmar, O., Maire, A., Morel, A., Dumont, B., & Datry, T. (2019). Structural and functional responses of invertebrate communities to climate change and flow regulation in alpine catchments. Global Change Biology, 25(5), 1612 1628. https://doi.org/10.1111/gcb.14581

Haase, P., Bowler, D. E., Baker, N. J., Bonada, N., Domisch, S., Garcia Marquez, J. R., Heino, J., Hering, D., Jähnig, S. C., Schmidt-Kloiber, A., Stubbington, R., Altermatt, F., Álvarez-Cabria, M., Amatulli, G., Angeler, D. G., Archambaud-Suard, G., Jorrín, I. A., Aspin, T., Azpiroz, I., … Welti, E. A. R. (2023). The recovery of European freshwater biodiversity has come to a halt. Nature, 620(7974), 582 588. https://doi.org/10.1038/s41586-023-06400-1

Floury, M., Usseglio-Polatera, P., Ferreol, M., Delattre, C., & Souchon, Y. (2013). Global climate change in large European rivers : Long-term effects on macroinvertebrate communities and potential local confounding factors. Global Change Biology, 19(4), 1085 1099. https://doi.org/10.1111/gcb.12124

Latli, A., Descy, J.-P., Mondy, C. P., Floury, M., Viroux, L., Otjacques, W., Marescaux, J., Depiereux, E., Ovidio, M., Usseglio-Polatera, P., & Kestemont, P. (2017). Long-term trends in trait structure of riverine communities facing predation risk increase and trophic resource decline. Ecological Applications, 27(8), 2458 2474. https://doi.org/10.1002/eap.1621

Floury, M., Usseglio-Polatera, P., Delattre, C., & Souchon, Y. (2017). Assessing long-term effects of multiple, potentially confounded drivers in ecosystems from species traits. Global Change Biology, 23(6), 2297 2307. https://doi.org/10.1111/gcb.13575

Le contenu de cette offre est la responsabilité de ses auteurs. Pour toute question relative à cette offre en particulier (date, lieu, mode de candidature, etc.), merci de les contacter directement. Un email de contact est disponible: juliette.vallin@inrae.fr

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