Simpson's Diversity Index

Simpson's Diversity Index (D) is a measure of biodiversity. It considers both the number of species present, and the relative abundance of each species.

Where:

• $n$ is the number of organisms on an individual species.
• $N$ is the total number of organisms of all species.

Example calculation:

Species	Number of Organisms (n)	n/N	(n/N)2
Daisies	4	0.31	0.096
Poppies	7	0.54	0.291
Holly Bush	2	0.15	0.023
	Total N = 13		Sum = 0.41
			1 - Sum = 0.59

So, the Simpson's Diversity Index for this dataset is 0.59. Since the value is closer to 1, biodiversity is considered high.

Practice Questions

Work out the Simpson's Diversity Index for the following dataset:

Your Answer (2 decimal places):

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