Ecological Succession
A series of predictable changes that occur in a community over time.
Ecosystems change over time especially after disturbances, as some species die out and new species move in.
Ecological model: a model scientists use to predict changes that will happen in an ecosystem that occurs over a long distance or over a long period of time.
number of different species present typically increases.
How many changes over time can you find?
Primary Succession Succession that begins in an area with no remnants of an older
community
No life present
only rock and eventually soil
Occurs at a very slow rate
Examples:
retreating glaciers
emerging islands
formation of new lake
Secondary Succession
The existing community almost completely destroyed by disturbances.
Proceeds faster than primary succession, because soil is present.
As a result, new and surviving vegetation can regrow rapidly, reach climax community faster
Examples:
Fire
Floods
Bulldozers
Climax Community Last stage of succession
Succession does not always follow the same stages for every community.
Healthy ecosystems will often reach the original climax community.
Example: succession caused by storms and forest fires
Some ecosystems, due to extensive human caused disturbances, may never fully recover
Examples: succession due to clearing and farming of tropical rainforests (deforestation)
Caused by pollution