Download Ecological Succession

Ecological Succession
definitions
• Ecological Succession:
• Gradual process of change and replacement of
some or all of the species in a community
• Two types
• Primary succession:
– Occurs on a surface where no soil exists
• Secondary succession:
– Occurs on a surface where an ecosystem has
previously existed
– More common
– Often the ecosystem was disturbed by humans
What happened before?
Primary succession: no soil
• Lava flow
• Glacier receding
• Rock avalanche
Secondary: starts with soil
• Forest fire
• Fallow fields
Leads to Primary or Secondary
succession?
Leads to Primary or Secondary
succession?
Leads to Primary or Secondary
succession?
• http://www.liveleak.com/view?i=fc8_1339108
936
Leads to Primary or Secondary
succession?
Primary:
• First soil must be established
• Pioneer species = the first to colonize
• usually mosses and lichen
Mosses and
Lichen
• trap moisture
• produce enzymes
that break up
small parts of rock
surface over time
Once soil is established…
• small plants/grasses
• Small bushes
• Pioneer trees
– Birch and Aspen are an example
– “Pioneer tree species, like aspen, prefer open
sunny environments and cannot grow well in the
shade of other trees.”
http://connectingthecoast.uwex.edu/Investigate/habitat.html
Finally…
• Climax Community
• Final, dynamic, yet stable, if not disturbed
Ecological Succession
• Each organism paves the way for the next to
establish
Fire and Succession
• Can cycle
• Can be healthy for regrowth and biodiversity
• Part of healthy forest management
Fire and Succession