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Ecosystems

Wetlands at risk

  • 3 things to know
  • Component 3 Section B

Overview

Four services provided by wetlands, main causes of wetland loss and loss of the Mesopotamian Marshes.

What you need to know

Answer each one before you reveal it.

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Key term

Define a wetland.

Key term

Why are wetlands so productive?

Key term

Name four services provided by wetlands.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define a wetland.

    Model answer

    A wetland is land that is saturated with water permanently or seasonally. Marshes, bogs, fens, mangroves, floodplains and shallow lakes all count as wetlands.

  2. 2

    Why are wetlands so productive?

    Model answer

    Wetlands combine abundant water, warmth and a continuous supply of nutrients from sediment. Swamps and marshes reach a net primary productivity of around 2,000 g m⁻² yr⁻¹.

  3. 3

    Name four services provided by wetlands.

    Model answer

    Wetlands store floodwater, filter pollutants, store carbon and provide nursery grounds for fish. Reed beds and peatlands also supply materials and fuel.

  4. 4

    How much of the world's wetland has been lost?

    Model answer

    Assessments published in 2018 estimated that around 35% of the world's wetlands were lost between 1970 and 2015. Losses continue fastest in Asia.

  5. 5

    Name the main causes of wetland loss.

    Model answer

    Drainage for agriculture, urban expansion, water abstraction and pollution are the main causes. Dams also cut off the flooding on which many wetlands depend.

  6. 6

    Why are peatlands important carbon stores?

    Model answer

    Permanent waterlogging stops dead plant material from decomposing, so carbon accumulates as peat. Peatlands cover about 3% of the land surface but hold roughly twice the carbon of all forests.

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