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   Amphibian Biomonitoring Guided Research: Data Analysis     
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  Research Question
  Background Info
  Research Methodology
  Data Submission
  Results of Study
  Data Analysis
  Further Research
  Research Values



Sample Analysis

           Sample Data                                            ;      Analysis

Blanchards Cricket Frog - 15                       Mean = (15 + 5 + 8 + 3 + 6)/5 = 7.4

Gray Treefrog                -  5                         Species Richness = total number of                                      &n bsp;                                                            species found

American Toad              -  8                                         &n bsp;           = 5

Northern Spring Peeper -  3                          Species Diversity = 0.74

Southern Leopard Frog  -  6                                     (as shown below)

Calculating diversity using the Simpson Diversity Index

Calculate the proportion of the total number of amphibians of each species (Pi).

Proportion species A (Pa) = number of species A/Total number of amphibians
Proportion species B(Pb) = number of species B/Total number of amphibians

To calculate the Simpson Diversity Index = 1 - sum(Pi)2

         (meaning add the proportion of each squared species and take it from 1)

Using the example above, you have 15 cricket frogs, 5 gray treefrogs, 8 american toads, 3 spring peepers, and 6 leopard frogs. You would calculate:

Diversity Index = 1- ((15/37)2 + (5/37)2 + (8/37)2 + (3/37)2 + (6/37)2)
Diversity Index = .74

This index ranges from zero to one and is literally a measure of the probability that two amphibianss taken at random from the sample are different species. A number close to zero means low diversity and it is likely you will get the same species of amphibian and a number close to one means high diversity.

  1999, KanCRN Collaborative Research Network