Measuring Species Richness

• Biodiversity


  Measure of species diversity in a given area
• Species diversity


  • Species richness
  • Species evenness
• Species richness


  Measure of the number of different species within a given area
• An area with a greater number of species will have a greater species richness
• Species richness can be a misleading indicator of diversity as it does not take into account the number of individuals of each species
• Species evenness


  Measure of the relative abundance of the different species within a given area
• Area 1 and Area 2

  • Both contain 4 tree species
  • Area 2 is dominated by one species and one species is very rare
• Although Area 1 and Area 2 have the same species richness, Area 1 has a higher species evenness and therefore a higher overall species diversity
• Conservationists often favour the use of an index of diversity (known as Simpson's Index) as it takes into account both species richness and evenness