Species Richness (AQA A Level Biology)

Species Richness

• Species richness is the number of species within a community

  • A community is a group of populations of different species living in the same place at the same time that interact with each other

• Species richness is the simplest way to measure species diversity

• A community with a greater number of species will have a greater species richness score

  • For example, a tropical rain forest has a very high number of different species so it would be described as species-rich

• Species richness can be a misleading indicator of diversity as it does not take into account the number of individuals of each species

  • For example, habitat A has 10 different plant species and habitat B has 7 different plant species

  • Habitat A would be described as being more species-rich than habitat B

  • However, in habitat A there is only one individual of each plant species present (10 individuals present) while in habitat B there are over 20 individuals of each species present (over 140 individuals present)

  • This example illustrates the limitations of species richness

• Conservationists often favour the use of an index of diversity as it takes into account species number and evenness