How to Calculate a Biodiversity Index

Part of the Biodiversity Counts Curriculum Collection.

The question of how many different species exist in a particular environment is central to the understanding of why it is important to promote and preserve species diversity.

A uniform population of a single species of plants adapted to a particular environment is more at risk if environmental changes occur. A more diverse population consisting of many species of plants has a better chance of including individuals that might be able to adapt to changes in the environment.

Scientists use a formula called the biodiversity index to describe the amount of species diversity in a given area. A simple biodiversity index is calculated as follows:

number of species in the area ÷ total number of individuals in the area = biodiversity index

For example, a 4 X 4 meter square area in a carrot patch has 300 carrot plants, all the same species. It has a very low biodiversity index of 1/300, or 0.003.

A 4 X 4 meter square area in the forest has 1 pine tree, 1 fern, 1 conifer tree, 1 moss, and 1 lichen, for a total of 5 different species and 5 individuals. The biodiversity index here is high, 5/5 = 1.

Student Activity

Calculating a Biodiversity Index
A Biodiversity Index gives scientists a concrete, uniform way to talk about and compare the biodiversity of different areas. Teach students how to calculate this number themselves.