Land use — AQA GCSE Combined Science
Test yourself on Land use with AQA GCSE practice questions.
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Land use explained
Land is a finite resource shared by humans and wildlife.
Read the full explanation
When people build houses, roads and factories, that ground is sealed or occupied, so plants cannot grow and animals lose feeding, shelter and breeding sites. Quarrying removes surface rock for materials such as limestone, destroying habitats and leaving bare, slow-to-recolonise ground. Farming uses large areas for crops, pasture and livestock, often replacing diverse ecosystems with few species; hedgerows and ponds may be removed to enlarge fields. Dumping waste covers land with landfill, spoil or rubbish, poisoning soil and water and smothering vegetation. Each activity lowers the area and quality of habitat, so populations shrink and biodiversity falls. For example, a new housing estate on a meadow removes the flowers, insects, birds and mammals that lived there, and the remaining wildlife must crowd into smaller patches.
The destruction of peat bogs, and other areas of peat to produce garden compost, reduces the area of this habitat and thus the variety of different plant, animal and microorganism species that live there (biodiversity).
Peat bogs are waterlogged, acidic wetlands built up over thousands of years from partly decayed plant material. Because decay is slow in waterlogged, oxygen-poor conditions, peat accumulates and stores carbon. These bogs support specialised plants such as sphagnum mosses, plus insects, birds, amphibians and many microorganisms. When peat is dug up or drained to make garden compost, the habitat area shrinks and its water balance changes. Species adapted to bog conditions lose their home, so the variety of plant, animal and microorganism species there falls, which is a loss of biodiversity. Draining also lets air reach the peat, so microorganisms decompose it and release stored carbon dioxide, adding to environmental harm. For example, extracting peat from a bog for compost can remove the moss layer, dry the remaining peat and leave a habitat where only a few generalist species survive.
The decay or burning of the peat releases carbon dioxide into the atmosphere.
Peat is partially decomposed plant material that accumulates in waterlogged, acidic bogs where oxygen is scarce, so decomposition is very slow. Carbon taken from the atmosphere by living plants becomes locked in the peat, making it a long-term carbon store. When peat is drained, dug up or burned, this stored carbon is no longer protected. Microorganisms decompose the exposed peat aerobically, respiring and releasing carbon dioxide. Burning peat in power stations or on managed land also releases carbon dioxide directly as the carbon in the peat combines with oxygen. In both routes the carbon store is converted into atmospheric carbon dioxide, a greenhouse gas, so land use that damages peat increases the concentration of carbon dioxide in the atmosphere.
Your focus
- State four human activities that reduce land available to other organisms.
- Describe how each activity removes or damages habitat.
- Explain how reduced habitat area leads to lower biodiversity.
Show all 9 objectives
- Describe what a peat bog is and why it supports distinctive species.
- Explain how peat extraction for compost reduces habitat area and biodiversity.
- Relate peat bog destruction to the loss of plant, animal and microorganism species.
- Describe how carbon stored in peat is returned to the atmosphere by decay or burning.
- Explain why draining or extracting peat increases the rate of carbon dioxide release.
- Apply the carbon store and transfer idea to evaluate the atmospheric effect of peatland land use.
Land use exam tips
Marking Points
- Building covers land with houses, roads and industry, removing the vegetation that other organisms depend on.
- Quarrying extracts rock and minerals, destroying habitats at the surface and leaving disturbed land that recolonises slowly.
- Farming occupies extensive areas for crops and livestock, often reducing species diversity compared with the original ecosystem.
- Dumping waste creates landfill and polluted ground, which smothers plants and harms animals and soil organisms.
- All four activities reduce the total area and quality of habitat available to other animals and plants, so populations and biodiversity decline.
- Peat bogs are habitats formed from partly decayed plant material in waterlogged, acidic, oxygen-poor conditions.
- Destroying or draining peat bogs removes the habitat for specialised plants, animals and microorganisms.
- Using peat to produce garden compost is a direct cause of peat bog destruction and area loss.
- Reduced habitat area lowers the variety of species living there, which is a reduction in biodiversity.
- Peat extraction also releases stored carbon as carbon dioxide when exposed peat is decomposed, so the harm extends beyond habitat loss.
- Peat is a store of carbon because it is formed from plant material that has only partially decomposed in waterlogged, low-oxygen conditions.
- Decay of peat is carried out by microorganisms that respire aerobically when the peat is drained or exposed to air, releasing carbon dioxide.
- Burning peat is a combustion reaction in which carbon in the peat reacts with oxygen, producing carbon dioxide.
- Both decay and burning transfer carbon from the peat store into the atmosphere as carbon dioxide, increasing the greenhouse gas concentration.
- Land use such as drainage, extraction or burning of peat bogs therefore reduces a carbon store and adds carbon dioxide to the atmosphere.
Examiner Tips
- 💡Name each activity from the statement and link it to a specific habitat loss, such as sealing soil or removing hedgerows.
- 💡Use the phrase finite land resource to explain why human use competes with wildlife.
- 💡Give one concrete example, such as a new road or landfill site, and state the effect on named organisms.
- 💡Link peat extraction to garden compost explicitly, because that is the use named in the statement.
- 💡Explain the sequence: habitat destroyed, area reduced, species variety reduced, biodiversity falls.
- 💡Mention that peat bogs store carbon, and that damage can release carbon dioxide, to show deeper understanding.
- 💡Name the process for each route: decay by microorganisms for drained peat, and combustion for burned peat.
- 💡State the carbon store being depleted and the atmosphere as the destination of the carbon dioxide.
- 💡Link the release to the greenhouse effect by naming carbon dioxide as a greenhouse gas rather than simply saying pollution.
Common Mistakes
- Thinking land use only affects the place where building happens; correction: roads, quarries, farms and landfill also fragment and pollute surrounding habitats.
- Confusing quarrying with mining for fossil fuels; correction: quarrying is surface extraction of rock such as limestone, and it removes habitat directly.
- Assuming farming always increases wildlife because it grows plants; correction: monoculture crops and cleared fields usually support fewer species than the habitat they replace.
- Saying peat is a type of soil that quickly regrows; correction: peat accumulates very slowly over thousands of years, so extraction is effectively permanent on human timescales.
- Thinking only plants are affected; correction: animals and microorganisms that depend on bog conditions also lose their habitat, so the whole community declines.
- Confusing biodiversity with the number of individual organisms; correction: biodiversity is the variety of different species and the range of habitats and genetic variation present.
- Thinking that decay of peat releases methane only: correction, aerobic decay of exposed peat releases carbon dioxide, and methane is associated with anaerobic conditions in waterlogged peat.
- Writing that burning peat releases carbon dioxide because plants respire: correction, burning is combustion of the carbon in peat, not respiration by plants.
- Assuming peat is a fossil fuel formed over millions of years like coal: correction, peat is recently accumulated partially decomposed plant material, although it is still a long-term carbon store.