spec points

the process of primary succession in the development of an ecosystem

• to include succession from pioneer species to a climax community

• deflected succession

intro

• Key Concepts:

  • Dynamic Ecosystems: Ecosystems are constantly changing, transitioning from simple to complex structures through succession.

  • Succession: The process of gradual ecological change where biotic (living) and abiotic (non-living) conditions evolve over time.

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  Primary Succession:

  • Occurs on newly formed/exposed land without prior life (e.g., volcanic rock, sand dunes, dried lakes) + gradually colonised by increasing no. of species

  • Stages:

    1. Pioneer Species: First colonizers (e.g., lichens, mosses) survive harsh conditions, break down rock, and create basic soil.

    2. Small Plants: Grasses and shrubs grow in shallow, nutrient-poor soil, further enriching it.

    3. Larger Vegetation: Deeper, nutrient-rich soil supports shrubs, small trees, and eventually large trees.

    4. Climax Community: Stable, self-sustaining ecosystem with dominant species.

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  Environmental Changes During Succession:

  • Species modify the environment, making it more suitable for other species but less hospitable to themselves.

  • E.g., lichens break rock into soil but are replaced by mosses and grasses as soil develops.

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  Secondary Succession:

  • Occurs in previously colonized areas cleared by disturbances (e.g., fires).

  • Starts with existing soil, progressing to a climax community faster than primary succession.

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  Conservation and Management:

  • Deflected Succession: Human activities (e.g., mowing, grazing) prevent succession, halting climax community development.

  • Benefits of Intermediate Stages:

    • Support diverse plant and animal species.

    • Preserve rare or ecologically important species (e.g., pollinators).

  • Methods to Prevent Succession:

    • Grazing: Animals eat growing shoots, preventing tree/shrub establishment.

    • Managed Burning: Controlled fires reset succession, maintaining early-stage ecosystems.

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  Examples:

  • Primary Succession: Lichens on volcanic rock gradually form soil, leading to grass, shrub, and tree growth.

  • Managed Moorlands (Scotland): Burning preserves heather and prevents spruce forest, supporting high biodiversity.