Succession

Front 1

What is succession?

Back 1

The process by which an ecosystem changes overtime.

Front 2

What can succession start with?

Back 2

Bare rock, a sand dune, a bucket of water etc

Front 3

What can we predict?

Back 3

The order in which plants will arrive and grow in the habitat. Different communities replace each other in a predictable way

Front 4

What is each plant community called?

Back 4

A sere

Front 5

What does each sere do?

Back 5

It changes the habitat in was that make it more habitable for the next sere.

Front 6

What is associated with each plant sere?

Back 6

A community of animals

Front 7

What is the final plant community called?

Back 7

The climax community

Front 8

What is a climax community?

Back 8

A stable and long lasting community

Front 9

How does a primary succession start?

Back 9

A pioneer species colonises the habitat, it must be adapted to cope with the harsh abiotic factors.

Front 10

What are some of these harsh abiotic factors?

Back 10

No soil,

Few minerals,

High light intensity,

Extremes of temperature,

Windy

Front 11

Why is light intensity high in initial conditions?

Back 11

There's no shade from other plants

Front 12

What happens in stage 1 of primary succession? (example)

Back 12

On bare rock, lichens are pioneers. They can survive with little water or soil. They anchor themselves in cracks and dissolve bare rock to get minerals. They can also withstand long periods of drought.

Front 13

What happens when the lichens die?

Back 13

They decompose to become organic matter. This is the beginning of a thin soil able to retain some moisture and slowly release nutrients through decomposition

Front 14

What can organic matter also be called?

Back 14

Humus

Front 15

What happens in stage 2 of primary succession?

(example)

Back 15

A moss sere grows+ some grasses. They can germinate and grow using moisture in the thin soil. When they die, their decomposition adds to the thin soil layer.

Front 16

What happens in stage 3 of primary succession?(example)

Back 16

A herbaceous sere (plants which need more water) grows as conditions improve.They have good seed dispersal mechanisms so large numbers of seeds dispersed by wind can grow in the thin soil. Decomp adds to the soil layer.

Front 17

How does the herbaceous sere affect abiotic factors and the previous sere?

Back 17

It out-competes the pioneers and moss for light and space.

They also reduce wind speed and light intensity and improve moisture and nutrient content of soil.

Front 18

What happens in stage 4 of primary succession?(example)

Back 18

A shrub sere grows as the soil has changed significantly, it is deeper, has more humus and has a pH closer to 7 than the underlying rock. Other abiotic conditions also improve.

Front 19

What do these larger plants form?

Back 19

The sub-climax community. They grow fast and out-compete the lower level shrub sere for light and space

Front 20

What happens in stage 5 of primary succession?(example)

Back 20

Woody trees grow slowly but when they are established, they out-compete the shrubs for light, minerals and water.

Front 21

What does this final sere provide?

Back 21

A diverse set of niches to support a large variety of insects and other animal species, A complex food web is now established with many trophic levels.

Front 22

What is a summary of the seres in this example?

Back 22

Pioneer sere

Moss sere

Herbaceous plant sere

Shrub sere

Woodland sere

Front 23

What does each seral community do?

Back 23

They change the conditions in such a way to promote the growth of the next sere. Each sere out-competes the previous one

Front 24

What does the species present depend on?

Back 24

The type of rock or substrate and the climate

Front 25

What is stage one of sand dune succession?

Back 25

Embryo dunes- these have small patches of marram grass self seeded or growing from rhizomes. Only pioneer species can grow in salty, dry nutrient poor conditions with extreme temperatures and shifting sand.

Front 26

What is stage two of sand dune succession?

Back 26

Mobile dunes (yellow dunes)- some large areas of bare moving sand, but more cover of marram grass.

Front 27

What is stage three of sand dune succession?

Back 27

Semi fixed dunes (grey dunes)- Smaller patches of bare sand with a greyish tinge. Many plants besides marram grass

Front 28

What is stage four of sand dune succession?

Back 28

Fixed dunes- almost complete vegetation cover. Marram grass is sparse and ultimately disappears. Many other plant species present

Front 29

What is stage five of sand dune succession?

Back 29

Dune slacks- areas which develop when sand is eroded so the water table is reached. The sand forms a damp depression and is prone to flooding. Large number of rabbits keep the vegetation short but cause blow outs when bare sand is exposed.

Front 30

What is stage six of sand dune succession?

Back 30

Climax- sand dunes normally develop into scrub, then woodland

Front 31

What does the climax community depend on?

Back 31

Abiotic conditions and climate

Front 32

When does secondary succession occur?

Back 32

When a climax community is removed or lost

Front 33

What happens in secondary succession?

Back 33

Pioneers and possibly other plants from later in the primary succession re-establish and succession starts again.

Front 34

How is the process compared to primary succession?

Back 34

It's much quicker as there's already a well developed soil and may contain lots of seeds

Front 35

What is plagioclimax?

Back 35

Where human activity deliberately stops or reverse a primary succession to maintain an earlier stage.

Front 36

What is a plagioclimax also known as?

Back 36

Deflected succession

Front 37

What do humans use to stop succession?

Back 37

Use animals to graze on plants which may move succession on