Positive Human Impacts On Ecosystems

Section 1 of 6Ways humans help ecosystems

Protected areas and reserves

• Protected areas and reserves Nature reserves and national parks set aside habitats where building, farming and hunting are restricted.
• This lets populations of rare species recover.

Breeding programmes and seed banks

• Breeding programmes and seed banks Endangered animals are bred in captivity and later released,
  • while seeds of rare plants are stored so the species cannot be lost completely.

Replanting and restoration

• Replanting and restoration Hedgerows, woodland and wetlands can be replanted after removal.
• Field margins left unfarmed give food and shelter to insects, birds and small mammals.

Reducing waste and pollution

• Reducing waste and pollution Recycling and cutting landfill reduce the land and pollution taken by rubbish.
• Cleaner energy lowers the carbon dioxide and acid gases released.

Laws and agreements

• Laws and agreements Governments restrict hunting, fishing quotas and trade in endangered species, and set limits on deforestation.

Section 2 of 6Why a biodiversity programme matters

1Habitat protected

• Habitat protected Organisms keep their food, shelter and breeding sites.

2Populations recover

• Populations recover Numbers of many species increase, so variety rises.

3Stable food webs

• Stable food webs Many producers and consumers mean the loss of one species is less damaging.

4Healthy ecosystem

• Healthy ecosystem Nutrients cycle well, pollination continues and the ecosystem is more resistant to change.

Section 3 of 6Conflicting pressures

Pressure	Why it conflicts with conservation
Cost	Programmes are expensive to set up and to monitor, and farmers may need subsidies for land left unfarmed.
Food security	Land kept for wildlife cannot be used to grow crops where food is short.
Protecting livelihoods	Predators or pests such as wolves or locusts may be killed to protect livestock and crops, upsetting food webs.
Growing population	More land is needed for housing, roads and farms, often taken from undisturbed, species-rich habitats.

Section 4 of 6Making a balanced judgement

1

Identify who benefits from the programme and who loses land, income or food.

2

Compare the long-term gains, such as stable ecosystems and resources for future generations, with the short-term costs.

3

Consider whether the programme can be checked and enforced, since unmonitored schemes may not work.

4

State a conclusion and support it with evidence from at least two of the pressures above.

Section 5 of 6Key terms

Term	Meaning
Biodiversity	The variety of living species in an ecosystem or on Earth.
Conservation	Actions that protect and manage species and habitats.
Field margin	A strip of uncultivated land left around the edge of a crop field.
Subsidy	Money paid by a government to make up for income lost or costs incurred.
Food security	Having reliable access to enough affordable, nutritious food.

Section 6 of 6Exam technique

1

Saying conservation is always good without mentioning the costs or competing land uses; exam answers need both sides.

2

Writing that biodiversity means the number of individuals rather than the number of different species.

3

Suggesting that killing a predator to protect livestock has no wider effect; it can disturb the whole food web.

4

Forgetting that schemes must be monitored and enforced to be effective.