Background:
Species diversity can be measured & described in many different ways.
Species evenness describes how evenly distributed all the species are in a community while species richness describes how many different types of species there are in a community.
Diversity Indices are one method used to measure species diversity in nature, and determine the degree of species evenness and species richness in an area. Using these calculations, ecologists can also attempt to assess the impacts of human development or pollution on an ecological community. When pollution is present or a human disturbance has occurred, diversity is typically low.
One diversity index is called the
Shannon Diversity Index (or Shannon Weiner Diversity
Index). In this lab you will calculate the Shannon Diversity Index for cars in a parking lot.
The calculations of species diversity, evenness, and richness are the same as for a natural environment. Example:
● Count the number of individuals of different “species” of cars in each parking lot
“community.”
● The number of “species “ or car types in each lot =
S
● Calculate relative abundance
(
p
)i
for each “species” in each “community.” (ex. The proportions of the “community” represented by each species.)
n
= number of “individuals” in “species” i i
And
N = total number of “individuals” of all “species”
● Calculate the
Shannon Diversity Index
(or Shannon Weiner Diversity Index):
means that you should perform the operations inside the [ ] for each “species” i , starting with “species” i
= 1. Add the result inside the [ ] for the next “species,” and so on. Stop when you get to the last “species” i = S
. Note that there is a negative sign before the summation sign (∑) which means that your answers will always be positive because the quantity
will always be negative.
Given a very large sample size, with more than 5 species, the