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Biodiversity and human impact
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Biodiversity is the variety of life in an area. Human activity can reduce it, but can also protect it.
Threats
Eutrophication: fertiliser runs into water, algae grow, block light, plants die, bacteria decomposing them use up oxygen, fish die.
Fish farming can spread disease to wild fish.
Non-indigenous species can outcompete native ones, like grey squirrels and red squirrels.
Deforestation destroys habitats.
Fish farming can spread disease to wild fish.
Non-indigenous species can outcompete native ones, like grey squirrels and red squirrels.
Deforestation destroys habitats.
Protecting biodiversity
Reforestation, conservation of habitats and species, breeding programmes, seed banks and protected areas.
Why it matters
High biodiversity makes ecosystems more stable. Many species provide food, medicines and materials.
Explain why fish die in a lake after fertiliser runs off nearby fields.
- Fertiliser makes algae grow quickly.
- Algae block light, so water plants die.
- Bacteria decompose the dead plants and use up oxygen.
- Fish suffocate.
Answer: Eutrophication uses up the oxygen.
Eutrophication, fish farming, invasive species and deforestation reduce biodiversity. Reforestation and conservation protect it. High biodiversity keeps ecosystems stable.
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