[organism]

[biofilms & biodiversity]

Let's Calculate Biodiversity
Try These Data

Species Richness & Simpson's Index: 3 Species | 6 Species
Species Richness & Shannon-Wiener Index: 3 Species | 6 Species



Using the species counts, fill out the following tables to calculate the species richness and the three biodiversity indices develop by Simpson.

Some Notation:



After you enter your answer(s) for each step, press the 'Check Answer' button. You can use the 'Clear Answer' button to clear the answer(s) for any part.

  1. Calculate the species richness (S).
    Fill in the box with your answer and press the 'check answer' button.

    Species Name
    # Found
    Pi
    Pi2

    Measure
    Value
    Whip Mud Worm
    8
     
     
    S

    Mussels
    20
     
     
    D
     
    Barnacles
    15
     
     
    1 - D
     
    Totals
    43
     
     
    1/D
     
      


  2. Calculate the Simpson index (D) value.

    First, calculate the percent of each species identified in the sample.
    Place your answers in the Pi column (up to 3 decimal places). Do not calculate the sum of the Pis (it will be done for you).

    Species Name
    # Found
    Pi
    Pi2

    Measure
    Value
    Whip Mud Worm
    8

     
    S

    Mussels
    20

     
    D
     
    Barnacles
    15

     
    1 - D
     
    Totals
    43

     
      


  3. Second, calculate the square of each percent for each species.
    Place your answers in the Pi2 column (again, up to 3 decimal places). Do not calculate the sum of the Pi2s (it will be done for you).

    Species Name
    # Found
    Pi
    Pi2

    Measure
    Value
    Whip Mud Worm
    8


    S

    Mussels
    20


    D
     
    Barnacles
    15


    1 - D
     
    Totals
    43


    1/D
     
      


  4. The sum of the Pi2 values is really Simpson's index (D). All that is left is for you to calculate Simpson's index of diversity (1 - D) and reciprocal index (1/D).
    Put your answer in the boxes for 1 - D and 1/D (again, up to 3 decimal places).

    Species Name
    # Found
    Pi
    Pi2

    Measure
    Value
    Whip Mud Worm
    8


    S

    Mussels
    20


    D

    Barnacles
    15


    1 - D

    Totals
    43


    1/D

      


  5. The final results looks like this!