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succession
- non-seasonal, directional, and continuous pattern of colonization and extinction on site
- process of community change over time
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degradative
- type of succession that results in depletion of resource "packets" (ie. dead body, leaf litter) by community of decomposers, detrivores, and scavengers
- decomposer: breaks down resource "packets"
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primary succession
- succession on a previously unoccupied site
- ex: production of lava fields; volcano erupts, lava flows down side, lava cools, plants begin to colonize
- ex: carcass succession because the site had not been colonized in any real sense before the new colonizing community members
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secondary succession
succession on a previously occupied site
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allogenic
- results from external geological, physical, and/or community forces
- ex:bacterial communites in the bottoms of lakes are ponds; rate of succession is dependent on rate of sedimentation from subsequent rains
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autogenic
succession driven by the action of the community members themselves
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classical view of succession
- Clement's monoclimax hypothesis
- if succession occurs, change will occur, but change will eventually stop and a given community will reach the monoclimax
- monoclimax: single, repeatable end
- ex: old field succession monoclimax = deciduous forests
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facilitation
- successional mechanism in which only certain pioneers can colonize
- pioneers alter site conditions
- later species require such site alteration
- competition eliminates early species
- sequence continues until facilitation stops
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tolerance
- succession mechanism in which all species can be a pioneers
- pioneers have little effect on subsequent recruitment
- competition eliminates early species
- sequence continues until only superior competitors are present (k-selection)
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inhibition
- opposite of facilitation
- all species can be pioneers
- pioneers make site less suitable for others
- succession stops at pioneers
- disturbance are required for continued succession and new, late colonizer
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