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Questions and Answers
What is the process of directional change in communities over time called?
Which type of succession occurs after a volcanic eruption?
What is the main factor that distinguishes primary from secondary succession?
Which event would most likely trigger secondary succession?
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What characteristic defines a sterile habitat in terms of plant life?
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What is the main difference between early successional species and late successional species?
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In the context of succession, what is the role of pioneer species?
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Which model of succession involves only the chance survival of different species and random colonization by new species?
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What common characteristic is shared by late successional species?
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In secondary succession, when can it occur?
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Which scenario involves an early successional species with a rapid growth rate and shade intolerance?
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'The invasion of alder dramatically changes soil pH, inhibiting the growth of early species' - This statement refers to which type of succession?
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'Species 2: moderate growth, longer life' - In which scenario is Species 2 described with this growth pattern?
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'Community progresses to ultimate stage — a stable climax community' - This statement aligns with which classical idea of succession?
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'Pioneer plants, as well as gulls, helped later plants establish' - This statement exemplifies which model of succession?
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Study Notes
Ecological Community
- An ecological community is an assemblage of populations living in a prescribed area or habitat
- Ecological communities are not stationary and continue to change over time
Succession
- Succession is the process of directional change in communities over time
- Two types of succession: primary succession and secondary succession
Primary Succession
- Primary succession is the colonization of new, sterile habitats
- Examples: after volcanic eruption or glaciations
- Characteristics of primary succession:
- Sterile habitats (no plants, no seeds, no bacteria in soil)
- Low or no nutrient availability
- Erosion
Primary Succession on Mount St. Helens
- Number of species occurring in 1-m^2 plot near the south cone of Mount St. Helens after its 1980 eruption
- Number of species reached a plateau 10-15 years after the eruption
Primary Succession: Glacial Moraines in Alaska
- Successional development following the retreat of glaciers
- Invasion of alder dramatically changes soil pH, inhibiting early species and facilitating later-stage species
Secondary Succession
- Secondary succession is the re-colonization of disturbed sites
- Examples: after fire, flood, avalanche
- Characteristics of secondary succession:
- Seed banks of plants that occur later in succession are present
- Bacteria and other soil organisms are present
Characteristics of Early and Late Successional Species
- Early successional species:
- Ability to grow in low-nutrient soils
- Fast growing
- Small seeds
- Long dispersal
- Short-lived
- Late successional species:
- Unable to survive in low-nutrient soils
- Slower growth
- Large seeds
- Short dispersal
- Longer life span
Concept of Succession
- Facilitation: early species in succession facilitate the arrival of late species
- Inhibition: species present early in succession inhibit the establishment of later species
- Tolerance: presence of early successional species is not essential; any species can start succession
- Random colonization: succession involves only the chance survival of different species and the random colonization by new species
Classical Idea of Succession (Facilitation Model)
- Pioneer species colonize habitat
- Each species modifies the environment, facilitating the arrival of later species
- Community progresses to an ultimate stage — a stable climax community
Case Study: Surtsey, Iceland
- Facilitation model of succession with a twist
- Pioneer plants and gulls helped later plants establish
- Number of higher plants present on the volcanic island of Surtsey, Iceland, after the eruption
Case Study: Lake Michigan Sand Dunes
- Plant succession on the sand dunes of northern Lake Michigan
- Examples: Marram grass, pine trees, willow shrubs, juniper bushes, and bracken fern
Case Study: Insects on Carrion
- Hypothetical diagram of arthropod succession on a carcass
- Populations of differing sizes of a given species as the succession proceeds
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Description
Test your knowledge on ecological succession with this quiz! Questions cover topics such as primary and secondary succession, the impact of species on soil pH, and the development of ecosystems after natural disturbances.
