Ecological Succession

Question 1

What is primary succession?

Answer 1

Changes in an ecosystem over a period of time when there was previously no life present

Question 2

When might primary succession occur?

Answer 2

• Following a volcanic eruption
• Following glacial periods

Question 3

What is secondary succession?

Answer 3

Changes in an ecosystem following a disturbance when there is existing soil

Question 4

When might secondary succession occur?

Answer 4

• Forest regrowth after logging
• Plant growth after flooding

Question 5

What is a sere?

Answer 5

The sequence of stages in ecological succession where a habitat develops into the climax community

Question 6

What are the 3 seres?

Answer 6

• Lithosere (bare rock)
• Hydrosere (water)
• Psammosere (sand)

Question 7

What are colonisers / pioneer species?

Answer 7

The first organisms to colonise an area during succession

Question 8

How are pioneer species adapted?

Answer 8

Adapted to the harsh abiotic conditions (e.g. wind speed, temperature)

Question 9

Which pioneer species are present in a lithosere?

Answer 9

Mosses and lichens

Question 10

Which pioneer species are present in a hydrosere?

Answer 10

Algae (e.g. blue-green algae)

Question 11

Which pioneer species are present in a psammosere?

Answer 11

Marram grass

Question 12

How do pioneer species change abiotic conditions?

Answer 12

Death and decay of species contributes to soil formation

Question 13

How does soil change as more species colonise an area?

Answer 13

Soil becomes deeper and more fertile

Question 14

What is the climax community?

Answer 14

The final stage of ecological succession from which there are no further changes

Question 15

What is the climax community in the UK?

Answer 15

Broadleaf woodland

Question 16

What happens in a lithosere?

Answer 16

1. Mosses and lichens colonise
2. Death and decay leads to humus and soil formation
3. More plant colonise and outcompete other species
4. Climax community is eventually formed

Question 17

What happens in a hydrosere?

Answer 17

1. Algae colonises
2. Death and decay leads to organic matter and sediment raising the lakebed
3. Continued death and decay dries the soil
4. Climax community is eventually formed

Question 18

What happens in a psammosere?

Answer 18

1. Marram grass colonises
2. Sand dunes become stabilised
3. Death and decay leads to humus and soil formation
4. Climax community is eventually formed

Question 19

What is a plagioclimax community?

Answer 19

An area or habitat in which human influences have prevented further succession

Question 20

What is another term for plagioclimax?

Answer 20

Deflected succession

Question 21

What are the 5 most common management practices in plagioclimax communities?

Answer 21

• Grazing (e.g. lowland heathland)
• Burning (e.g. upland moorland)
• Mowing
• Coppicing
• Pollarding