Biodiversity Measuring Biodiversity - Mrs. Gamzon's...

Measuring Biodiversity

• The Earth is contains a tremendous number of life forms. • There are different ways to quantify how biodiverse

an ecosystem is.

Biodiversity

Species Richness: The number of species in a given area.

Species Evenness: The measure of whether a particular ecosystem is numerically dominated by one species or are all represented by similar numbers of individuals.

Biodiversity

High Evenness Low Evenness

Identical Richness

Measuring Biodiversity

• Shannon Index • Increases as both the richness and the evenness of a

community increase. • Makes it difficult to compare communities that differ

greatly in richness.

Pi = ni/Nni = number of individuals in a given speciesN = total number of individuals in the community

The higher the number the more biodiverse!

Measuring Biodiversity

• Simpson’s Index • This index is used to measure the dominance of a

community, which is the opposite of evenness. • As D increases, the diversity decreases.

Pi = ni/Nni = number of individuals in a given speciesN = total number of individuals in the community

Values are between 0 and 1 with 1 being a monoculture.