"Coevolution of species' range and niche in changing environments"Polechová, JitkaI will focus on developments of fundamental theory of species' range and our understanding of resilience of natural populations in changing environments. What rate of temporal change can a species still withstand, and what are the effects of temporal variation on its range and niche? Both spatial and temporal variation influence genetic variation - a core determinant of the rate of adaptation. Genetic variance generally increases with both spatial and temporal variation, yet with temporal variation, the increase is only sustained under limited conditions. In both cases, there are limits to the maximum rate of change - and they are not independent of each other. I use dimensional analysis and simulations to integrate earlier theories and highlight the effect of the interaction between demography and evolution under both spatial and temporal variation. In populations with large densities (neighbourhood sizes), increasing spatial variability enables adaptation to faster temporal change, for a broad range of conditions. In contrast, as neighbourhood size of the population decreases, the interaction becomes more complex: adaptation to a temporally changing optimum may become hindered as spatial heterogeneity increases. I explain when the threshold arises at which genetic drift overwhelms adaptation to combined spatial and temporal change. |
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