How do Ecological Interactions Influence Adaptation to the Abiotic Environment? – InterAdapt

In the face of global environmental change, the need for understanding the limits of ecological niches and constraints on adaptation is becoming increasingly pressing. This question is often formulated with respect to the abiotic, physical environment, which determines the fundamental niche of a species, as measured by its environmental tolerance curve. Yet, both within- and between-species ecological interactions are crucial not only to relate this fundamental niche to the realized niche in the field, but also to understand evolution of the abiotic niche itself. Indeed, tolerance of abiotic stress and ecological interactions involve functional traits that are likely to trade-off in adaptive evolution. And when a species occupies a broad environmental gradient, the strength and nature of ecological interactions shape variation in selective pressures and evolutionary dynamics along this gradient. The main goal of InterAdapt is to provide a unified understanding of the contribution of ecological interactions to adaptation to the abiotic environment and evolution of the fundamental niche. To reach this goal, we will investigate a rich array of interconnected questions, using a diversity of approaches: theoretical modelling, analysis of natural populations, and experimental evolution in the laboratory. We will use as model species Dunaliella salina, a unicellular green alga that can tolerate a vast range of salinities through outstanding physiological mechanisms. We will evolve this species in the laboratory with different interactors (competitor, predator, mutualist), and across salinity, uncoupling biotic and abiotic gradients that are correlated in the field. We will analyze the evolved responses throughout the genotype-environment-phenotype map, including the underlying molecular mechanisms of plasticity. We will then compare these results to the genetic and phenotypic structure across natural salinity gradients in Mediterranean salterns.