levo

Ecosystems

Sub-climax and plagioclimax communities

  • 3 things to know
  • Component 3 Section B

Overview

Sub-climax community, three physical factors that can arrest succession and edaphic factor.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

What is a sub-climax community?

Key term

Name three physical factors that can arrest succession.

Key term

What is an edaphic factor?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is a sub-climax community?

    Model answer

    A sub-climax community is one where succession has been halted before the climatic climax. A persistent physical factor holds it at an earlier stage.

  2. 2

    Name three physical factors that can arrest succession.

    Model answer

    Waterlogging, salinity and exposure to wind can all arrest succession. Thin or unstable soils and repeated fire have the same effect.

  3. 3

    What is an edaphic factor?

    Model answer

    An edaphic factor is a soil characteristic that influences vegetation. Waterlogging, salinity, acidity and depth are the main edaphic controls.

  4. 4

    Explain how waterlogging arrests succession.

    Model answer

    Saturated ground excludes oxygen from the soil, so tree roots cannot respire. The community stays as bog or fen rather than developing into woodland.

  5. 5

    Explain how salinity arrests succession.

    Model answer

    Salt draws water out of plant roots by osmosis, so only halophytes survive. A saltmarsh therefore stays at the salt-tolerant stage while the tide still reaches it.

  6. 6

    Explain how exposure arrests succession.

    Model answer

    Strong, salt-laden wind damages buds and shoots and dries out leaves. Vegetation on an exposed cliff top stays as low heath rather than growing into woodland.

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book
2Open book
3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Coastal Landscapes
Glaciated Landscapes
Changing Places
Water and Carbon Cycles

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

One therefore represents 250 metres.
centimetremetremillimetre

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

ACustomary rights are often unwritten.
BA government can lease the same land to an investor.
COccupants then have no legal defence against eviction.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

Due west is a bearing of 270°.
TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Ecosystems, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Or £46 a year, about £3.83 a month. Cancel anytime.