What is the difference between succession and variation?
Succession - replacement of one dominant species by another until a climax community is reached. Pioneer community -> pioneer species (autotrophic, high reproduction, extremophile, N2 fixing…) -> intermediate community (pioneer species die, humus in soil, able to support secondary coloniser)… -> until climax community (stable).
Biodiversity is greatest in the intermediate community - in the climax community, the most adapted species would have outcompeted the less adapted. Primary succession - new area of land that has become accessible. Secondary succession - only soil present, no living organisms (forest fire…)
Deflected succession - reach plagioclimax community due to human action (e.g continually mowing grass halts succession in your garden).