My broad research interests lie in understanding how biodiversity distributes on Earth and predicting how species respond to global change. A phenomenon that particularly interests me is the large-scale migrations and movements of highly-mobile organisms, and my work aims to improve understanding of the causes and consequences of migration at large scale. My research integrates spatially-explicit analyses and mechanistic modeling using large observational and ecological datasets.

Explaining the seasonal distribution of birds: the global ecology of migration
Collaborators: Andrea Manica (U. Cambridge), Ana Rodrigues (CNRS)

This is the main research project on which I have been working during my PhD and first postdoc. I mapped, for the first time, global diversity patterns associated with bird migration and found that despite the great biological and ecological diversity in migratory birds, strong spatial patterns emerge when all species are pooled together (Somveille et al. 2013). Then, I focused on exploring the processes underpinning these patterns. I found strong support for the hypotheses that migratory birds move to their breeding grounds to exploit a seasonal surplus in energy and resources and avoid competition from residents, and then redistribute to the nearest suitable non-breeding grounds (Somveille et al. 2015). I also showed that species' contemporary migratory destinations (i.e. the combination of their breeding and non-breeding ranges) are such that they allow them to track a temperature regime throughout the year (but not habitat), to escape local competition and reach areas with better access to resources, and to minimize the spatial distance travelled, within the limitations imposed by the geographical location of each species (Somveille et al. 2018a). These results paved the way for a mechanistic understanding of the global seasonal distribution of birds. Using bird migration as a natural experiment and a mechanistic model of the seasonal geographical distribution of land bird species, I showed for the first time that birds distribute across the world in the most energy-efficient way (Somveille et al. 2018b). The results provide strong evidence that bird species appear to minimize the energy used for survival while targeting areas with maximum energy available, considering the distributional strategies of all the other species, with migration allowing species to further optimize energy budget in the face of seasonality and competition. This study has far reaching implications for understanding the global distribution of biodiversity.
Using the mechanistic model that I developed, I am now working on reconstructing the global seasonal distribution of birds back to the Last Glacial Maximum. I also aim to make a set of predictions for the impact of future global change.

Global distribution of migratory bird species.

Extreme long-distance migrations. Lines connect the centroid of species' breeding and non-breeding ranges.

Predicting population-level migration pathways
Collaborator: Christopher Revell (U. Cambridge)

Collaborating with a physicist, we developed a novel individual-based mechanistic model of migratory movement patterns. We combined data on wind velocity and food density to produce an "environmental potential" landscape in which seabirds navigate during their non-breeding season. The model only contains two unknown parameters and was able to predict well observed migration pathways for various populations of Black-browed Albatross in the Southern Ocean (Revell & Somveille 2017). Our model improve our understanding of the environmental factors influencing bird migration and can be used to predict the emergence of migration pathways at the population level under various environmental conditions.
We are now working on adapting the model to simulate migration pathways for various land bird species.
All the simulation code from the project is available here.

Simulated migrations of Black-browed albatrosses. Predicted movements out of South Georgia and Kerguelen islands.

Spread of information in populations of mobile animals
Collaborators: Robin Thompson, Josh Firth, Ben Sheldon (U. Oxford), Lucy Aplin, Damien Farine (Max Planck).

I am interested in exploring how movement affects the spread of socially-transmitted information (but also propagules) in populations of highly-mobile organisms.
The social transmission of information plays a key role in the lives of many animal species, and understanding how it is influenced by ecological and social processes is crucial if we want to understand the conditions under which animal culture (i.e. regional variations in behaviour that are stable through time) emerges. I collaborated with researchers at Oxford and the Max Planck Institute for Ornithology to develop a spatially-explicit model of the spread of behavioural preference, which integrates two processes: the movement of individuals across the landscape and conformist social learning (i.e. the disproportionate likelihood to copy the most common behavioural trait). The model is able to replicate a real-world cultural diffusion experiment that was performed on great tits, Parus major, in Wytham Woods, UK (Aplin et al. 2015 Nature), and it allows to make a range of predictions for the emergence of animal culture under various initial conditions, habitat fragmentation, movement patterns and strength of conformist bias. Our results reveal a strong interplay between movement and conformity for determining whether local traditions establish across a landscape (i.e., some part dominated by one behavioural preference while the rest is dominated by the alternative preference) or whether the whole population adopts one single behavioural preference (Somveille et al. 2018c). This work opens up new research path for exploring the role of movement in the emergence of animal culture.

Spread of information across Wytham Woods. First row: no conformity bias; second row: conformity weak relative to movement; third row: conformity strong relative to movement. In orange: behavioural preference s1; in blue: behavioural preference s2

Other Macroecological work

Brood parasitism and the evolution of cooperative breeding in birds
Collaboration with William Feeney (U. Queensland), Naomi Langmore (ANU)

In this collaborative work with researchers at Cambridge and in Australia (Feeney, Medina, Somveille et al. 2013), we found that reciprocally selected interactions may explain the strong association between brood parasitism and cooperative breeding in birds, opening up new research avenues for the field. My specific contribution was to conduct the spatial analysis comparing the global distributions of avian brood parasites and cooperative breeding species.

Analysing the global distribution of bird plumage patterns
Collaborators: Thanh-Lan Gluckman (College de France), Kate Marshall (U. Cambridge)

Using a global dataset on avian plumage patterns and phylogenetic comparative analyses, we tested for the first time for an association between habitat and plumage patterns across the world's birds, but found no evidence for it as well as little phylogenetic signal (Somveille et al. 2016).