Ecological Succession

Ecological succession is defined as, A change in the community in which new populations of organisms gradually replace existing ones.

There are two types of ecological succession

1) Primary Succession

Occurs where there is no soil, e.g. after a   volcanic eruption or a glacial retreat.
Pioneer organisms
Simple plants first – no or shallow roots.
Gradual influx of more complicated and larger plants as the habitat changes
Unfavourable for life at first.
Ends with a “climax community” – ecosystem stays constant, provided there are no changes in abiotic influences.

2) Secondary Succession

Community development in the areas that were previously occupied by other community.

Occurs after a disturbance. E.g., loss of trees after disease, Fire or wind, deforestation etc.
Conditions are favourable, as soil and nutrients are already present.
More rapid than primary succession