Summary
The gradual, directional change in a community over time, primary on bare rock and secondary after disturbance.
In depth
Primary succession starts on bare substrate (lava, glacier retreat): pioneer species such as lichens and mosses make soil, then grasses, shrubs and trees follow. Secondary succession follows disturbance of existing soil (fire, farming) and is faster. A climax community may be stable but disturbances are common.
Early succession species are fast-growing r-strategists; later ones are shade-tolerant K-strategists. Facilitation, tolerance and inhibition are mechanisms. Disturbance resets succession.
Example: fire-adapted forests rely on periodic burning.
Climax community ideas have changed: Clements saw succession as ordered development toward a stable climax, while Gleason stressed individualistic responses of species. Today succession is seen as variable, with multiple outcomes depending on chance, dispersal and disturbance, and communities rarely reach a fixed state. Facilitation (early species improve conditions), tolerance and inhibition are three models (Connell and Slatyer).
In Glacier Bay, Alaska, ice retreat since 1794 shows a sequence from bare rock to mosses, dryas, alder (nitrogen-fixing), willows and eventually spruce and hemlock forest over about 200 years. Secondary succession after fire or farm abandonment is faster, since soil and seeds remain.
Example: Krakatoa, sterilised by the 1883 eruption, was recolonised and covered with forest within about 50 years.
Frequently asked questions
What is Ecological Succession?
The gradual, directional change in a community over time, primary on bare rock and secondary after disturbance.
Which area of biology covers Ecological Succession, and how advanced is it?
Ecological Succession is one of the 54 topics in Ecology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Ecology, Competitive Exclusion, Survivorship Curves.
Can you give an example of Ecological Succession?
Glacier Bay in Alaska shows primary succession over about 200 years.
What should I learn before Ecological Succession?
Work through the Beginner topics in Ecology first, such as Ecology, Ecosystem, Biotic and Abiotic Factors, then return to Ecological Succession. Intermediate topics assume the Beginner vocabulary.
What topics are related to Ecological Succession?
The closest topics to Ecological Succession are Ecology, Competitive Exclusion, Survivorship Curves, Carrying Capacity. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Ecological Succession?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Ecological Succession. To practise the whole of Ecology, use the Ecology quiz.
How is Ecological Succession different from Ecology?
Ecological Succession: The gradual, directional change in a community over time, primary on bare rock and secondary after disturbance. Ecology: The study of how organisms interact with each other and with their physical environment. Read both side by side and note what each one explains.
How should I study Ecological Succession step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Ecology and explain the difference aloud. Finally, take the Ecology quiz and come back to this page for any question you miss.