BIOL-208 Lecture Notes - Lecture 18: Primary Succession, Climax Community, Secondary Succession
17 Dec 2016
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Succession and stability
- Introduction
- Succession: gradual change in plant and animal communities in an area post
(after) disturbance
- Pioneer community: plants/lichens that colonize within first few years after
disturbance
- Primary succession: on newly exposed geological substrates
- Secondary succession: following disturbance that does not destroy soil
- In most cases of disturbance, secondary succession is first
- Climax communities: late successional community that remains stable until
disrupted by disturbance
- Disclimax community: maintained only under continual disturbances
- Community changes during succession
- During succession nearly every aspect of community structure changes
- Richness
- Dominance and evenness
- Diversity
- Composition
- Ecological processes leads to succession
- Changes can be:
- Predictable and follow assembly rules
- Unpredictable and stochastic
- Primary succession after glacier
- Closest to the glacier, where it is still melting, has very few species
- Farther and farther from the glacier shows more species and is more
dense
- Secondary succession
- Canada’s dominant community
- Frequently disturbed by humans and natural fires
- Ignore the extremes
- Kills some plants
- Increases light penetration allowing for woody recruitment and
early colonizers
- Increase nutrient availability
- Stimulate microbial activity
- Difference in species between recently burned and not burned for some
time
- Pre-fire: much variation in forest composition
- Post fire: regular pattern changes over time
- Moderate fire: no primary succession
- Spruce budworm
- Chronosequence: sites that share similar attributes but are of
different ages. Since many processes in forest ecology take a long
find more resources at oneclass.com
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Document Summary
Succession: gradual change in plant and animal communities in an area post (after) disturbance. Pioneer community: plants/lichens that colonize within first few years after disturbance. Primary succession: on newly exposed geological substrates. Secondary succession: following disturbance that does not destroy soil. In most cases of disturbance, secondary succession is first. Climax communities: late successional community that remains stable until disrupted by disturbance. Disclimax community: maintained only under continual disturbances. During succession nearly every aspect of community structure changes. Closest to the glacier, where it is still melting, has very few species. Farther and farther from the glacier shows more species and is more dense. Frequently disturbed by humans and natural fires. Increases light penetration allowing for woody recruitment and early colonizers. Difference in species between recently burned and not burned for some time. Post fire: regular pattern changes over time. Chronosequence: sites that share similar attributes but are of different ages.
