G4: Conservation of Biodiversity

G.4.1 Explain the use of biotic indices and indicator species in monitoring environmental change. -Specie indicate environmental conditions due to their tolerance limits(sensitive)-Used to consider environmental change over time(historical records)-Used to monitor changes in the future(response to development project)-Used to determine impacts spatially(e.g. impact of sewage pollution in river)E.g. Lichen - Sulphur dioxide from burning fossil fuels will kill lichens

Biotic index = Σ (n x a)/Nn= number of individual of a speciesa= sensitivity scoreN= total number of organismsSample calculation:Site A:(n x a)=(10x3)+(10x1)+(10x4)+(7x0)+(7x1)+(5x1)+(5x1)+(5x4)+(4x22)+(2x1)+(1x2) = N= 3+1+4+0+1+1+1+4+22+1+2 =Biotic index = 5.225Site B:Biotic index = 4.01

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