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Abstract

In my thesis, I studied the effect of environmental changes such as the induction of abiotic stress and spatial structure in the link between evolution and ecology with the aim to develop an understanding when and how often ecological and evolutionary dynamics interplay to affect the fate of natural populations. The first chapter is a conceptual work discussing the processes through which abiotic stress can enhance or impede the link between evolution and ecology. Here I synthesize the knowledge from the fields of evolutionary biology and ecology to discuss the potential processes through which abiotic stress can affect the link between evolution and ecology. I identify gaps in our knowledge and propose further experimental and theoretical directions that need to be investigated. This chapter has been an important driver for my thesis. In the second chapter, I follow one of the experimental directions that I propose in my first chapter. Based on the experimental model system, with the alga Chlorella variabilis as a host and the virus PBCV-1, I combined a mathematical and an experimental approach to test if abiotic stress can break the link between resistance evolution and ecology through changes in the strength of the host resistance-growth trade-off and host mortality rate. I use an experimental approach to verify the predictions of my mathematical model that an abiotic stressor could break the link between evolution and ecology by increasing the strength of the trade-off between host resistance and growth rate and increasing host mortality. This chapter underlines the importance of combining mathematical modelling approaches with experimental evolution. It is also a significant step in developing a predictive understanding of when and how eco-evolutionary dynamics might occur in nature. In the third chapter, I extend the mathematical model of chapter two that describes the host-virus community and I add a predator for the host as an additional consumer for the algal host. My motivation is to investigate the role of another environmental factor such as spatial structure for eco-evolutionary feedback dynamics. Already in the first chapter I highlight the potential of dispersal to affect the link between evolution and ecology and thus eco-evolutionary feedback dynamics. In my chapter III, I model the eco-evolutionary dynamics of the three species first in one patch and then I extend it to more complex spatial scales of eight patches that are connected by dispersal. This chapter shows that when there is spatial homogeneity, dispersal network structure has no significant effect on the species eco-evolutionary dynamics as well as on species coexistence. In addition, I test the effect of dispersal network structure in the absence of eco-evolutionary dynamics (i.e., only ecological dynamics) and I find that the species specific interactions play a more important role for species coexistence compare to dispersal network structure. This chapter is an important the first step towards testing more realistic cases and predictions from metapopulation theory.