Range Expansions

I am interested in the expansion of microbial populations in spatially-heterogeneous and temporally-fluctuating environments. I use protists, bacteria and yeast as model organisms.

In https://doi.org/10.1073/pnas.1809587115, I studied the competition dynamics between two strains of yeast whose relative fitness changed when grown at 30C and at 12C. I showed that mechanical interactions between the two strains cause each strain to survive for very long times at the temperature in which they are at a disadvantage, allowing them to recover at the frontier of the colony following temperature changes.

In http://doi.org/10.1073/pnas.1321167110, we studied the effect of demographic stochasticity on the variability of replicated experimental invasions. Furthermore, we verified Fisher's prediction for the speed of an invasion front relating the local growth rate and movement behavior to the invasion speed at the macroscopic scale.

In http://doi.org/10.1111/oik.04330, we investigated how the interaction between demographic stochasticity and the heterogeneity of resource distributions affect the speed of range expansion, via a combination of laboratory experiments with the alga Euglena gracilis and modeling via stochastic reaction-diffusion equations accounting for demographic stochasticity. We showed that demographic stochasticity causes local extinctions in unfavorable regions of the landscape which cause a reduction in the speed of range expansions.