Landscapes, cataclysms and population explosions

A common phenomenon in biological systems is for an environmental catastrophe to trigger population explosions by one or more rare species, causing them to burst into prominence, suddenly replacing populations that were dominant previously. A common mechanism is for a rare population to be suppressed by dominant populations until a cataclysm, such as a fire, a storm or a cometary impact triggers explosive growth. The example of forest change during the postglacial period is considered here in detail. Simulations show that dispersal across the landscape is important in the process: abrupt transitions and explosive growth occur only if dispersal distances are normally short.