AQA · A-Level · Geography
Course version: 7037 · Version from Sept 2018
The effects of human activity on succession – illustrated by one…
Full specification wording
Ecosystems in the British Isles over time: The effects of human activity on succession – illustrated by one plagioclimax such as a heather moorland.
Human activities such as deforestation, grazing, and controlled burning can arrest natural succession, preventing an ecosystem from reaching its climatic climax.
Checked against the AQA 7037 specification (opens in a new tab) on .
- Point 3 of 3
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Human activities such as deforestation, grazing, and controlled burning can arrest natural succession, preventing an ecosystem from reaching its climatic climax. This deflected succession results in a plagioclimax community. A prime example is the heather moorland of the UK uplands, which is actively managed for red grouse shooting and sheep grazing. Rotational burning (muirburn) on a 10 to 15-year cycle destroys tree saplings and encourages new, nutritious heather shoots. Without this continuous human intervention, the moorland would naturally undergo secondary succession, eventually reverting to scrub and then temperate deciduous or coniferous woodland, depending on the specific altitude and local climate.
What earns the marks
- Define a plagioclimax as a stable plant community that has arisen as a result of human intervention deflecting natural succession.
- Identify specific human activities that arrest succession, such as controlled burning, grazing by livestock, and deforestation.
- Explain the management of heather moorlands, detailing how rotational burning prevents the establishment of larger shrubs and trees.
- Describe the ecological consequences of these activities, such as reduced biodiversity but high dominance of specific species like heather (Calluna vulgaris).
Common mistakes and how to put them right
Describing heather moorland as a natural climatic climax.
Put it right: Clearly identify heather moorland as a plagioclimax maintained only through continuous human management.
Stating that burning destroys the ecosystem.
Put it right: Explain that controlled rotational burning rejuvenates the heather, providing nutritious shoots for grouse while preventing tree succession.
Using the terms primary succession and secondary succession interchangeably when discussing human impacts.
Put it right: Specify that if human management stops, the plagioclimax will undergo secondary succession towards the climatic climax.
Exam tips
- Always name a specific plagioclimax environment, such as the North York Moors, to ground your explanation in a real-world context.
- Clearly distinguish between the human activities that created the plagioclimax (e.g., historical deforestation) and those that maintain it (e.g., grazing and burning).
- Discuss the concept of deflected succession, showing a clear understanding of what the ecosystem would become if human intervention ceased.
Try the lesson
The start of the Ecosystems in the British Isles over time: The effects of human activity on succession – illustrated by one plagioclimax such as a heather moorland. lesson, made from checked teaching notes for this specification point.
Have a go first
Which human activity is primarily responsible for maintaining heather moorland as a plagioclimax community in the British Isles?
Listen
Human activities such as deforestation, grazing, and controlled burning can arrest natural succession, preventing an ecosystem from reaching its climatic climax. This deflected succession results in a plagioclimax community. A prime example is the heather moorland of the UK uplands, which is actively managed for red grouse shooting and sheep grazing. Rotational burning (muirburn) on a 10 to 15-year cycle destroys tree saplings and encourages new, nutritious heather shoots. Without this continuous human intervention, the moorland would naturally undergo secondary succession, eventually reverting to scrub and then temperate deciduous or coniferous woodland, depending on the specific altitude and local climate. A strong answer earns marks for these points. Define a plagioclimax as a stable plant community that has arisen as a result of human intervention deflecting natural succession. Identify specific human activities that arrest succession, such as controlled burning, grazing by livestock, and deforestation. Explain the management of heather moorlands, detailing how rotational burning prevents the establishment of larger shrubs and trees. Describe the ecological consequences of these activities, such as reduced biodiversity but high dominance of specific species like heather (Calluna vulgaris). A common slip: Describing heather moorland as a natural climatic climax. Instead, Clearly identify heather moorland as a plagioclimax maintained only through continuous human management. Exam tip: Always name a specific plagioclimax environment, such as the North York Moors, to ground your explanation in a real-world context.
See it
Key words
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Plagioclimax
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Human intervention
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Succession
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See every definition
- Plagioclimax
- A stable plant community that has arisen as a result of human intervention deflecting natural succession.
- Human intervention
- Human activities such as deforestation, grazing, and controlled burning that can arrest natural succession and prevent an ecosystem from reaching its climatic climax.
- Succession
- The natural process that would otherwise lead an ecosystem to its climatic climax, but which can be arrested by human activity.
Label the diagram
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1Box 1
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3Box 3
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