3.4.6 Biodiversity

• Biodiversity- the variety and the number of living organisms in a particular area, made of three components (species, genetic and ecosystem diversity)
• Species diversity- the number of different species and the number of individuals of each species living within the community
• Genetic diversity- the variety of genes possessed by the individuals that make up a population of a species
• Ecosystem diversity- the range of different habitats (small local habitats to the entire Earth- biome)
• Species richness- measurement of the number of different species in a community, simple way of measuring biodiversity, but population size is not accounted for
• Index of diversity- a measure the number of individuals in a species compared to the total number of species in the community
• $d=$$N(N−1)/Σn(n−1)$

  N is the total number of individuals collected.

  n is the number of individuals in the species.

  The higher 'd' is, the more diverse the area is- if it is 1, all the individuals are of the same species.
• What farming practises can impact biodiversity?

  • Deforestation
  • Monoculturing
  • Pesticides
  • Destruction of habitats (removing hedgerows)
  • Herbicide
• Woodland clearance and hedgerow removal- reduces the number and species of trees, destroys habitats (removes food and homes), birds migrate which can cause further loss of biodiversity
• Herbicides- reduces plant diversity which reduces food sources for other insects causing migration which interrupts the food chain, so birds and other mammals are affected
• Pesticides- directly reduces the diversity of pests and indirectly affects the diversity of any organisms which feed on the pests
• Monoculture crops- less choice of crops means less organisms are able to be supported, leading to more migration and less biodiversity
• Conservation techniques for farmers:

  • Allowing parts of the farm to grow wild
  • Bringing back hedgerows and animal strips- allows animals to walk through the fields
  • Wildflower strips around the edges of fields- encourages birds and predatory insects
• Conservation benefits agriculture (farming) by maintaining the environment and providing new sources of food.