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.