BIO120H1 Lecture Notes - Lecture 22: Soil Seed Bank, Temperate Deciduous Forest, Pioneer Species
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BIO120H1 Full Course Notes
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Communities dynamics: predictable successional change in plant communities. Pioneer species get in first (from dispersal or seed bank in soil) Soil-building processes and shade thought to be critical. Happens at many levels, but most heavily studied in human-impacted landscapes in eastern north america, especially old-field succession from abandoned land to forest. Agricultural succession: farms being abandoned in east, allowed to revert to natural vegetation. Vegetation changes spontaneously as the vegetation itself modifies the environment. Annual weeds, good dispersal ability, make a lot of offspring. Ends at climax stage, stable equilibrium, no more change. Climax forest: set of trees, all able to grow under own shade, able to replace themselves indefinitely. Start with nothing, get pioneers, go through series of stages, stabilize. Primary succession: new substrate created, no pre-existing vegetation (uncommon) How a vegetation community builds up where there was nothing before. New land created, no pre-existing soil or vegetation.
