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Simpson's Diversity Index

Simpson's Diversity Index. What it measures. 3 separate measures of  diversity.  We will use Simpson's Reciprocal Index. . 2.The higher the D value, the greater the diversity.  The lowest D can be is one, and the highest is the number of different species found. . What it measures.

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Simpson's Diversity Index

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  1. Simpson's Diversity Index

  2. What it measures • 3 separate measures of  diversity.  We will use Simpson's Reciprocal Index.  2.The higher the D value, the greater the diversity.  The lowest D can be is one, and the highest is the number of different species found. 

  3. What it measures c. Diversity is a function of two measures: richness and abundance.    i. Richness is the number of species per sample.  Does not consider the abundance of species present.  Ex: One daisy has a much influence on richness as does a patch of 1000 buttercups.  ii. Evenness is a measure of the relative abundance of difference species. 

  4. Pair - Share Two different fields are sampled for wildflowers. The sample from the first field consists of 300 daisies, 335 dandelions and 365 buttercups. The sample from the  second field comprises 20 daisies, 49 dandelions and 931 buttercups.  Evaluate richness and evenness.

  5. 2. To determine the number of samples needed - plot number of species found until the number plateaus ...this indicates your sample size is large enough to be accurate.  Method • Sample the area using a quadrat 

  6. 4.  Plug numbers into formula.  Method 3.  Record the number of species present (identifying is not necessary as long as different species can be distinguished). Index value D = N=n = Σ= total # of organisms of all species found number of individuals of a particular species  “Sum of” so add ‘em up

  7. Predict the D value for the following situations - Polluted stream - Old growth forest - Area cleared for power lines - Agricultural area - Estuary (between river & ocean) - Our Campus What this tells you High D.. suggests stable and/or ancient site Low D...suggests disturbance or limiting factors

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