Directional change in the composition of a plant community is called succession. Primary succession occurs if there is no remnant of a prior biological community. If a volcano erupts lava that cools to rock, then life can take hold. Disturbances such as fire, flood, windstorms that destroy plants but leave a remnant of the biological community V in soil, seeds, resprouts V lead to secondary succession. We can think of a shifting mosaic of patches in the environment.
Disturbance resets a patch to age zero and it then proceeds to change through succession.
Each patch is a different age since disturbance and has a different disturbance history. Thus there can be more different kinds of environments in the same local area. This would be true because species that are adapted to more extreme conditions could coexist in this middle ground. Perhaps a better idea is the variable disturbance hypothesis that says that varying frequency and intensity in a place will increase coexistence. Another aspect of diversity and species specialization is space.