Quantitative Biology Colloquium

The competitive exclusion principle states, in its most basic form, that a number of species competing for a smaller number of resources cannot coexist. Both experimental and theoretical studies have shown that in some instances environmental fluctuations can facilitate coexistence for competing species. Hutchinson conjectured that one can get coexistence because nonequilibrium conditions would make it possible for different species to be favored by the environment at different times. In this talk I will look at how random environmental fluctuations can facilitate coexistence. I will show that, contrary to Hutchinson's explanation, if one switches randomly between two environments in which species 1 persists and species 2 goes extinct, so that the same species is favored at all times, one can still get coexistence.