AQA A-Level Geography Paper 1, June 2025: Question 6

Question 6 Ecosystems under stress

Total

Qu Part Marking guidance

marks

06 1 Outline the concept of climatic climax. 4

AO1=4

Point marked

Allow 1 mark per valid point with extra mark(s) for developed points (d).

For example:

Notes for answers

AO1

• This is the final stage of succession in an area where the dominant

vegetation has reached equilibrium with the surrounding environment

(1). No further changes will occur unless the environment changes or

a new more suitably adapted species is introduced (1) (d). Any new

species would need to outcompete the existing dominant vegetation in

the community (1) (d). This vegetation community is best adapted to

the prevailing climatic conditions of the area (1) (d).

• To reach this stage pioneers initially colonise the area requiring nothing

more than light, heat, water and the most basic nutrients found on bare

rock (1). Examples includes moss and lichen (1) (d).

• When these pioneers die (and with some weathering of parent rock) a

very basic soil forms allowing other species to colonise (1). The

addition of organisms (decomposers) also aids this process (1) (d).

• New species continue to hold the niche but they themselves are

outcompeted (succession) until the climax is achieved (1).

• Max 1 for example e.g. temperate deciduous woodland (1).

– A-LEVEL GEOGRAPHY – –

The notes for answers are not exhaustive. Credit any valid points.

06 2 Analyse the data shown in Figure 11. 6

AO3=6

AO3 – Analysis relates to identification of pattern and trends as well as

anomaly. There is also opportunity to manipulate data.

Mark scheme

Level 2 (4–6 marks)

AO3 – Clear analysis of the quantitative evidence provided, which makes

appropriate use of data in support. Clear connection(s) between different

aspects of the data and evidence.

Level 1 (1–3 marks)

AO3 – Basic analysis of the quantitative evidence provided, which makes

limited use of data and evidence in support. Basic connection(s)

between different aspects of the data and evidence.

Notes for answers

AO3

• Tropical wet and moist store most of their carbon in the biomass

40 compared to the other biomes. For example, Tropical moist stores

over 150 gigatonnes of carbon in its biomass compared to 25 gigatons

for warm temperate moist, a difference of over 125 gigatons.

• In terms of total biomass, Tropical moist may at first glance appear to

be the biggest store at around 300 gigatons (155 biomass, 75 topsoil

and 70 subsoil). However, this is comfortably exceeded by the Boreal

moist biome which has around 365 gigatons stored in total (25 in

biomass, 160 in topsoil and 190 in subsoil). This is a difference of 65

gigatons.

• Tropical wet and moist also represent an anomaly in that they are the

only two biomes with more carbon in the biomass than the combined

soils total, e.g. tropical wet has around 140 gigatons in biomass

compared to a combined 125 gigatons in the two soil types.

• There are three biomes with more carbon in the topsoil compared to

the subsoil. The difference appears to be around 5-10 gigatons.

• Boreal moist has the largest differential between topsoil and subsoil; a

difference of around 30–35 gigatons.

– A-LEVEL GEOGRAPHY – –

Credit any other valid analysis.

06 3 Using Figure 12 and your own knowledge, assess impacts of human 9

activity on the cycling of nutrients in a temperate deciduous AO1=4

woodland. AO2=5

AO1 – Knowledge and understanding of nutrient cycling. Awareness of

ecosystem responses to changes in one or more of their components.

AO2 – Application of knowledge and understanding to assess the impact

of human activity on nutrient cycling.

Mark scheme

Level 3 (7–9 marks)

AO1 – Demonstrates detailed knowledge and understanding of concepts,

processes, interactions and change. These underpin the response 41

throughout.

AO2 – Applies knowledge and understanding appropriately with detail.

Connections and relationships between different aspects of study are

fully developed with complete relevance. Assessment is detailed and

well supported with appropriate evidence.

Level 2 (4–6 marks)

AO1 – Demonstrates clear knowledge and understanding of concepts,

processes, interactions and change. These are mostly relevant though

there may be some minor inaccuracy.

AO2 – Applies clear knowledge and understanding appropriately.

Connections and relationships between different aspects of study are

evident with some relevance. Assessment is evident and supported with

clear and appropriate evidence.

Level 1 (1–3 marks)

AO1 – Demonstrates basic knowledge and understanding of concepts,

processes, interactions and change. This offers limited relevance with

inaccuracy.

AO2 – Applies limited knowledge and understanding. Connections and

relationships between different aspects of study are basic with limited

relevance. Assessment is basic and supported with limited appropriate

evidence.

Notes for answers

AO1

• Mineral nutrient cycling.

• Ecosystem responses to changes in one or more of their components

or environmental controls.

• Factors influencing the changing of ecosystems including human

exploitation.

• Succession and climatic climax as illustrated by lithoseres.

• The characteristics of the climatic climax: temperate deciduous–A-LEVEL GEOGRAPHY– –

woodland biome.

42 AO2

• Deforestation is one obvious activity which would impact on mineral

nutrient cycling. This would immediately remove the biomass store

and also remove the transfer to the litter.

• Afforestation would have the opposite effect to the above but this

depends on the species planted. An orchard or a plantation for the

timber industry would inevitably change the size of the biomass store

depending upon what was planted.

• Similarly, if trees are planted for specific purposes, such as Christmas

trees (fir and spruce conifers), these are likely to have negative

impacts on the litter as they are evergreen. Needles are less easy to

decompose and release fewer nutrients into the soil.

• If trees are removed and nothing is replanted, the area becomes at risk

of increased loss by leaching, thus increasing the size of that pathway

out of the system. Similarly, loss by run off is likely to increase with no

canopy to protect the soil underneath.

• Input from dissolved nutrients in rainfall may increase with no canopy

to intercept vegetation. With more water reaching the ground there

may be more infiltration and percolation. This may possibly increase

the input of nutrients from weathered rock.

• Knowledge of specific nutrients are not required but some reference to

nitrogen, phosphorus and potassium etc.–A-LEVEL GEOGRAPHY – –

Credit any other valid assessment.

06 4 Assess the potential impact of climate change upon people living in 9

savanna grasslands. AO1=4

AO2=5

AO1 – Knowledge and understanding of pressures facing the savanna

grasslands.

AO2 – Application of knowledge and understanding to assess the

potential impact of climate change on this region for people, plants and

animals.

Mark scheme

Level 3 (7–9 marks)

AO1 – Demonstrates detailed knowledge and understanding of concepts,

processes, interactions and change. These underpin the response

throughout.

AO2 – Applies knowledge and understanding appropriately with detail.

Connections and relationships between different aspects of study are

fully developed with complete relevance. Assessment is detailed and

well supported with appropriate evidence.

Level 2 (4–6 marks)

AO1 – Demonstrates clear knowledge and understanding of concepts,

processes, interactions and change. These are mostly relevant though

there may be some minor inaccuracy.

AO2 – Applies clear knowledge and understanding appropriately.

Connections and relationships between different aspects of study are

evident with some relevance. Assessment is evident and supported with

clear and appropriate evidence.

Level 1 (1–3 marks)

AO1 – Demonstrates basic knowledge and understanding of concepts,

processes, interactions and change. This offers limited relevance with

inaccuracy.

AO2 – Applies limited knowledge and understanding. Connections and

relationships between different aspects of study are basic with limited

relevance. Assessment is basic and supported with limited appropriate–A-LEVEL GEOGRAPHY– –

evidence.

Notes for answers

AO1

• The concept of the biome. The global distribution of major terrestrial

biomes.

• Savanna grassland to include:

o the main characteristics of the biome

o ecological responses to the climate, soil and soil moisture budget –

adaptations by flora and fauna

o human activity and its impact on the biome

o typical development of issues in the biome to include changes in

population, economic development, agricultural extension and

intensification, implications for biodiversity and sustainability.

44 AO2

• The climate of the savanna is considerably varied depending on

location. It is characterised by a wet and dry season, but within this

both precipitation and temperature show considerable variation.

• Species are highly adapted to these conditions: the baobab and acacia

are two examples of species adapted to cope with the high

temperature and lack of all-year-round water; grasses are well adapted

to cope with drought and fire.

• Most agree that temperatures are set to increase generally across the

savanna and rainfall will become less reliable and predictable in terms

of volume and timeliness.

• The ramifications of this for people are expected to be substantial.

• The grasses provide the basis of the food chain, whilst the rains

provide the water for the arable farmers in the savanna. This has

implications for both the pastoralists and arable farmers.

• Similarly, the wildlife is wholly dependent on the seasonal rains for

food from grass or water for drinking. Those species further up the

food chain have little chance of surviving if there is no water and their

food source is under threat.

• Other industries such as tourism are also totally (albeit indirectly)

reliant on a reliable climate. Hotels require substantial quantities of

water for guests and most tourists are in these areas to visit the wildlife

of the game reserves.

• It is hard to see anything other than a very challenging future for the

people and ecosystem of the savanna grasslands.

Credit any other valid approach. Assessment–A-LEVEL GEOGRAPHYshould be based upon– –

preceding content.

06 5 With reference to a coral reef that you have studied, assess the 20

sustainability of human activity within the area. AO1=10

AO2=10

AO1 – Knowledge and understanding of the pressures facing coral reefs.

AO2 – Application of knowledge and understanding to assess the

sustainability of coral reef exploitation.

Notes for answers

AO1

• The distribution and main characteristics of coral reef ecosystems. 45

• Environmental conditions associated with reef development. The

following aspects should be examined with reference to a named,

located coral reef:

o factors in the health and survival of reefs

o natural: water temperature, acidity, salinity, algal blooms

o human activity and its impact: major drainage basin schemes,

onshore development, desalination, pollution, tourism, fishing

o future prospects for coral reefs.

AO2

• The direction of the response will depend on the choice of supporting

material.

• Most are likely to argue that current practices exploiting coral reefs are

unsustainable. There are many threats facing the reef systems.

Pollution (from factories on land and boats at sea), overfishing

(particularly dangerous practices include dynamite fishing as well as

the use of cyanide), souvenir hunting as well as coral extraction for use

in industries such as construction.

• Probably the biggest threat is from climate change. Though the human

activity has a limited link to the area itself, the impacts certainly are

within the area. Coral bleaching occurs when the temperatures

become too high for the coral. The algae dies and the mutually

dependent symbiotic relationship is destroyed.

• Natural predators such as the crown of thorns starfish may be

increasing in number due to certain human activities. Offshore

dredging for example is thought to increase the amount of

phytoplankton which the starfish larvae feed off.

• Finally, increased frequency and intensity of tropical storms may also

be indirectly attributable to human activity through climate change.

Whilst coral protects coastlines from the worst impacts of tropical

storms, the associated storm surges can do enormous damage to the

coral once they strike the coast.

• There are a number of success stories in sustainable coral

management. In Australia, work has been undertaken to promote the

growth of algae on corals which are more tolerant to increased global

temperatures, surviving in temperatures up to 31 °C.

• Corals in the Gulf of Aqaba, in the northernmost region of the Red Sea,

are capable of withstanding ocean temperature fluctuations that

normally cause coral bleaching elsewhere.–A-LEVEL GEOGRAPHYIdentifying the durability of– –

the reef may be key to maintaining the protection of coral reefs in other

46 regions of the world with vulnerability to ocean temperature

increases. In 2020, experts applied to UNESCO to designate the

2500-mile coral reef of the Red Sea a Marine World Heritage Site.

• Dense root systems of mangrove trees capture sediments moving

down rivers. Mangrove helps to protect the coastline and prevents

tides and hurricanes from eroding. The trees also shield coral reefs

and seagrass meadows from being smothered in sediment. Protecting

mangrove is increasingly becoming seen as having an associated

positive impact on coral as often they occupy adjacent locations in the

same places.

• Overall, the future is not looking positive but there are measures in

place to try to improve this outlook. – A-LEVEL GEOGRAPHY – –

Credit any other valid approach.

Marking grid for Question 06.5

Level/ Criteria/Descriptor

Mark

Range

Level 4 • Detailed evaluative conclusion that is rational and firmly based on knowledge and

(16–20 understanding which is applied to the context of the question. Interpretations are

marks) comprehensive, sound and coherent (AO2).

• Detailed, coherent and relevant analysis and evaluation in the application of knowledge

and understanding throughout (AO2).

• Full evidence of links between knowledge and understanding to the application of

knowledge and understanding in different contexts (AO2).

• Detailed, highly relevant and appropriate knowledge and understanding of place(s) and

environments used throughout (AO1).

• Full and accurate knowledge and understanding of key concepts, processes and

interactions and change throughout (AO1).

• Detailed awareness of scale and temporal change which is well integrated where

appropriate (AO1).

Level 3 • Clear evaluative conclusion that is based on knowledge and understanding which is

(11–15 applied to the context of the question (AO2).

marks) • Generally clear, coherent and relevant analysis and evaluation in the application of

knowledge and understanding (AO2).

• Generally clear evidence of links between knowledge and understanding to the

application of knowledge and understanding in different contexts (AO2).

• Generally clear and relevant knowledge and understanding of place(s) and

environments (AO1).

• Generally clear and accurate knowledge and understanding of key concepts and

processes (AO1).

• Generally clear awareness of scale and temporal change which is integrated where

appropriate (AO1).

Level 2 • Some sense of an evaluative conclusion partially based upon knowledge and

(6–10 understanding which is applied to the context of the question (AO2).

marks) • Some partially relevant analysis and evaluation in the application of knowledge and

understanding (AO2).

• Some evidence of links between knowledge and understanding to the application of

knowledge and understanding in different contexts (AO2).

• Some relevant knowledge and understanding of place(s) and environments which is

partially relevant (AO1).

• Some knowledge and understanding of key concepts, processes and interactions and

change (AO1). 47

• Some awareness of scale and temporal change which is sometimes integrated where

appropriate. There may be a few inaccuracies (AO1).

Level 1 • Very limited and/or unsupported evaluative conclusion that is loosely based upon

(1–5 knowledge and understanding which is applied to the context of the question (AO2).

marks) • Very limited analysis and evaluation in the application of knowledge and understanding.

This lacks clarity and coherence (AO2).

• Very limited and rarely logical evidence of links between knowledge and understanding

to the application of knowledge and understanding in different contexts (AO2).

• Very limited relevant knowledge and understanding of place(s) and environments (AO1).

• Isolated knowledge and understanding of key concepts and processes (AO1).

• Very limited awareness of scale and temporal change which is rarely integrated where

appropriate. There may be a number of inaccuracies (AO1).

Level 0 • Nothing worthy of credit.

(0 marks)