Missions

In the context of the current biodiversity crisis, there is a pressing need to understand how biodiversity patterns have been created and assembled. The number of species is not distributed evenly around the globe (Rohde et al. 1992, Pennisi 2005, Mittelbach et al. 2006) as there are many more species in the tropics than in the temperate regions. This pattern called the latitudinal diversity gradient is arguably the most famous unexplained biogeographical pattern on Earth (Pianka 1966, Rohde 1992, Mittelbach 2006). Since its first description at the beginning of the XIXth century by Humboldt (Hawkins 2001, Lomolino et al. 2010), it has now been described among most clades of animals, plants and microbes (Hillebrand 2004, Rolland & Freeman 2023) and it remains one of the greatest unsolved mysteries of evolution and ecology (Pennisi 2005).

A classic explanation of the latitudinal diversity gradient is that the increase of species diversity in the tropics should be associated to an increase in biotic interactions ('diversity begets diversity' hypothesis, e.g. Mayer & Pimm 1997, Schemske 2009), that ultimately also increase speciation rate. Although this 'biotic interaction' hypothesis is well known in evolutionary biology, it has not been properly tested at a global scale (Moles & Ollerton 2016). In theory, biotic interactions should impact the shape of phylogenies (Moen & Morlon 2014, Condamine et al. 2019) and the evolution of phenotypes of species. The divergent selection associated with competition is expected to cause shifts in trait evolution in order to partition resources among competitors (“character displacement”, Schluter 2000, Pfennig & Pfennig 2009). New models have recently been developed to specifically detect these biotic interactions using large phylogeny and trait datasets (see Drury et al. 2021).

Activities

In this project, the Postdoc will study whether biotic interactions vary with latitude, using phylogenetic models of trait evolution. More specifically, she/he will test the hypothesis that species interactions are stronger in the tropics, using models of phenotypic evolution which detect interactions among lineages. The Postdoc will test whether tropical clades show more support for diversity-dependent phenotypic evolutionary models (Drury et al. 2016) than for other models not including biotic interactions. All of those models will be fitted on mega-phylogenies and exceptionally large dataset of traits for nearly 54 000 species of vertebrates to test this hypothesis.

Skills

The candidate should have a PhD in Biology/Evolutionary Biology and skills in bioinformatics and macroevolution (ideally models of phenotypic evolution). The technical challenge will be to manage large datasets for many clades and fitting a large number of models. Softwares will be mostly in R but will likely involve other bioinformatics tools (Bash, python) and the use of computational clusters. The candidate should be motivated to interact with other scientists in the group (currently 3 PhDs and 1 postdoc), proficient in English, with a good publication record.

Work Context

He/she will be mainly supervised by Jonathan Rolland (CNRS, at the University of Toulouse), in close collaboration with other members of the latitudinalMysteries ANR project: with international collaborators (J. Drury and D. Schluter) and other french collaborators (such as J. Clavel, J. Chave, G. Grenouillet, J. Murienne, P. Tedesco, A. Fouquet). Our lab combines genetics/genomics, phylogenetics, niche modelling, paleontology and computational methods to investigate how diversity is distributed on earth and how latitudinal gradients have been shaped through time.

Constraints and risks

At a local scale, the postdoc will be involved in the organization of seminars/journal clubs in the laboratory Centre de Recherche sur la Biodiversité et l'Environnement (CRBE). The project will also benefit from the rich scientific environment in the laboratory CRBE in the university of Toulouse.
Toulouse is the main city in the South-West of France with a lively atmosphere, located one hour from the Pyrenees mountains, two hours away from Montpellier and three hours from the Atlantic Ocean.
The successful candidate is supposed to move to France (ideally from the beginning of 2026). Please apply on the "Portail emploi" of the CNRS with
(1) a short statement (~1 page) that describes your research accomplishments and motivation for applying, including the contact information for two references (2) a CV.

For more information about research in our lab, please visit:
https://jorolland.wordpress.com , https://crbe.cnrs.fr and https://scholar.google.com/citations?user=RibBKAYAAAAJ&hl=fr