3.2.5: Ecosystems at a local scale

Question 1

Ecological succession

Answer 1

The replacement of a species by others overtime

Question 2

Serial stage

Answer 2

Each period and location when a particular type of vegetation is the most important in an ecosystem.

Question 3

Climax community

Answer 3

Final stage of development where the ecosystem has reached equilibrium with the local climate

Question 4

UK’s climax community

Answer 4

deciduous woodland,

oak, birch and ash

Question 5

Ecosystems can develop into 4 different conditions

Answer 5

hydrosere
halosere
lithosere
psammosere

Question 6

Hydrosere

Answer 6

An that ecosystem that develops in fresh water conditions

Question 7

Halosere

Answer 7

An that ecosystem that develops in salt water conditions

Question 8

Lithosere

Answer 8

An that ecosystem that develops on bare rock

Question 9

Psammosere

Answer 9

An that ecosystem that develops on bare sand

Question 10

Types of succession

2

Answer 10

primary and secondary

Question 11

Primary succession

Answer 11

Occurs on a surface that has had no previous succession/vegetation.

Question 12

Secondary succession

Answer 12

Occurs on a surface that has been previously vegetated but has since been modified or destroyed.

Question 13

Example of primary succession

Answer 13

vegetation growing on a solidified bare rock after a lava flow

Question 14

Example of secondary succession

Answer 14

regrowth of vegetation after a forest fire

Question 15

Sub-climax

Answer 15

The development of an ecological community to a stage short of the expected climax due to a natural factor.

Question 16

Examples of a natural factor which causes a sub-climax

3

Answer 16

repeated forest fires, underlying geology producing poor soils, too windy

Question 17

Plagioclimax

Answer 17

Where repeated disturbances by human activity can deflect succession, preventing it from reaching its climax community.

Question 18

Examples of human activity which causes a sub-climax

6

Answer 18

fire clearance
deforestation
animal grazing
agriculture
industrialisation
tourism

Question 19

Process of succession

4 steps

Answer 19

1. Colonisation by pioneer species
2. Weathering of a rock + decomposition of pioneer species, soil layer forms, allowing a field layer to form
3. Taller plants will start to dominate sunlight and provide shelter fort smaller plants to grow underneath
4. Each new serial stage shows an increase in height of plants and number of species

Question 20

Field layer

Answer 20

Soil with herbs and grasses

Question 21

Sand dune formation process

Answer 21

1. Wind is slowed down when it comes into contact with an object and deposits sand, pioneer species, embryo dunes
2. Fore dunes
3. Yellow dunes
4. Grey dunes
5. Deciduous woodland with mature trees

Question 22

Yellow dunes

Answer 22

are well established with vegetation eg: marram grass form a ridge, the sand is yellow coloured.

Question 23

Fore dunes

Answer 23

develop as sand accumulates, more vegetation begins to grow eg: lyme grass.

Question 24

Grey dunes

Answer 24

Have grey sand due to the mixing of hummus and organic matter with sand, they have much more vegetation with perennial species and moss and lichen. Fixed and permanent dunes.

Question 25

Mobiles dunes

Answer 25

can be destroyed by severe storms

Question 26

Example of mobile dunes

3

Answer 26

embryo dunes
fore dunes
yellow dunes

Question 27

Embryo dunes

Answer 27

Formed by wind deposited sand on objects such as driftwood, vegetation and flotsam

Question 28

Flotsam

Answer 28

debris in the water perhaps from shipwrecks

Question 29

Plagioclimax casestudy

Answer 29

Heather moorland: The North Yorkshire Moors

Question 30

Cycle of growth of heather

natural

Answer 30

1. Pioneer phase, heather seedlings are established and rapid root growth occurs
2. Building phase, most productive and valuable phase, vigorous growth, increase biomass
3. Mature phase, ground cover becomes discontinuous and the plants become woodier
4. Degenerate phase, growth slows and old branches die

Question 31

North Yorkshire Moors

how did the ecosystem form and characteristics

Answer 31

• heavily managed by people
• areas used to be covered in deciduous woodland but 3000yrs ago the climax community was cleared to farm
• exposed ground became eroded and leaching occurred
• thin, acidic, less fertile soil remained and then became colonised by hardy plants such as heather

Question 32

How is the plagioclimax maintained in the North Yorkshire Moors

Answer 32

controlled burning of heather keeps the max. amount of heather possible in the building phase so lots of edible green shoots are available

Question 33

Arresting factors

Answer 33

Interruptions which prevent the climax community from being reached.

Question 34

Main arresting factors on Surtsey

2

Answer 34

coastal erosion and extremely harsh conditions

Question 35

Species on Surtsey

Answer 35

30 established plant species in 2008
initial colonisation by lichens
permanent bird colonies
nesting birds and wind bring new plant species