Nick Barton abstract
Nick Barton, Institute of Science and Technology, Austria:
What limits a species' range?
If a population fails to adapt to its environment, its population size will fall. This makes adaptation harder, both because random fluctuations become stronger, and because the population may be swamped by immigration. This positive feedback can set a sharp limit to a species' range, even when the environment changes gradually. I describe two kinds of model: a large number of subpopulations, with no spatial structure, and a gradient in one-dimensional continuous space. In both cases, analytical approximations can be found when very many genes affect fitness.