Maintaining biodiversity: These include:

The idea

This lead-in line introduces a list of named strategies that humans use to protect biodiversity, so you must be able to recall and explain each one. Biodiversity means the variety of different species and the range of genetic variation within them, and it matters because stable ecosystems depend on many interlinked organisms. Human activity such as deforestation, pollution and overfishing reduces this variety, so conservation methods aim to keep populations viable and habitats intact. The listed methods are breeding programmes for endangered species, protection of rare habitats, reintroduction of hedgerows and field margins, reduction of deforestation and carbon dioxide emissions, and recycling rather than dumping waste. For each, link the action to its effect: for example, a zoo breeding programme raises numbers of a threatened animal, then offspring are released into protected habitat.

What earns the marks

• Biodiversity is the variety of species and the genetic variation within populations, and maintaining it supports ecosystem stability.
• Each strategy works by increasing population size, preserving habitat area or quality, or reducing the human pressures that cause decline.
• Answers should link a specific method to a specific biodiversity benefit, such as captive breeding increasing numbers before release into the wild.
• Positive and negative human impacts on biodiversity can be compared, for example conservation versus deforestation or overfishing.

Common mistakes and how to put them right

• Treating biodiversity as simply the number of individual organisms.

  Put it right: It is the variety of species and genetic variation, not total abundance.

• Listing a method without explaining how it maintains biodiversity.

  Put it right: Add the mechanism, such as habitat protection preserving breeding sites.

• Confusing recycling with reducing carbon dioxide emissions.

  Put it right: Recycling cuts waste and resource extraction, while lowering emissions mainly limits climate-related habitat change.

Exam tips

• Use the command word to judge depth: describe needs the method, explain needs the method plus its effect on biodiversity.
• Name at least three different strategies and give a distinct benefit for each rather than repeating one idea.
• Link answers to a real context, such as hedgerows providing corridors that connect isolated populations.