Biodiversity

• What is biodiversity?

  ● Variety of living organisms

  ● Can relate to a range of habitats, from a small local habitat to the Earth
• What is a community?

  All populations of different species that live in an area.
• What is species richness?

  A measure of the number of different species in a community
• What does an index of diversity do?

  Describes the relationship between:

  1. The number of species in a community (species richness)

  2. The number of individuals in each species (population size)
• Suggest why index of diversity is more useful than species richness

  ● Also takes into account number of individuals in each species

  ● So takes into account that some species may be present in small or high numbers
• Describe how index of diversity values can be interpreted

  ● High → many species present (high species richness) and species evenly represented

  ● Low → habitat dominated by one / a few species
• Explain how some farming techniques reduce biodiversity

  1 Removal of woodland and hedgerows

  2 Monoculture (growing one type of crop)

  3 Use of herbicides to kill weeds :

  ● Reduces variety of plants

  ● So fewer habitats and niches

  ● And less variety of food source

  4 Use of pesticides to kill pests :

  Predator population of pest decreases
• Explain the balance between conservation and farming

  ● Conservation required to increase biodiversity

  ● But when implemented on farms, yields can be reduced, reducing profit / income for farmers

  ○ Eg. by reducing land area for crop growth, increasing competition, increasing pest population

  ● To offset loss, financial incentives / grants are offered
• Give examples of how biodiversity can be increased in areas of agriculture

  ● Reintroduction of field margins and hedgerows (where farmers only grow one type of crop)

  ● Reduce use of pesticides

  ● Growing different crops in the same area (intercropping)

  ● Using crop rotation of nitrogen fixing crops instead of fertilisers