Biodiversity in the Library
Simpson's Diversity Index is a measure of diversity. In ecology, it is often used to quantify the biodiversity
of a habitat. It takes into account the number of species present, as well as the abundance of each species.
Biological Diversity - the great variety of life. Biological diversity can be quantified in many different
ways. The two main factors taken into account when measuring diversity are richness and evenness.
1. Richness - Richness is a measure of the number of different kinds of organisms present in a particular
area. For example, species richness is the total number of different species present in a community. Some
communities may be simple enough to allow complete species counts to determine species richness.
However, this is often impossible, especially when dealing with insects and other invertebrates, in which
case some form of sampling has to be used to estimate species richness.
2. Evenness - Evenness is a measure of the relative abundance of the different species making up the
richness of an area. To give an example, we might have sampled two different fields for wildflowers. Both
samples have the same number of species (3) and the same total number of individuals (1000). The total
number of individuals in sample 1 is quite evenly distributed between the three species. In the second
sample, most of the individuals are buttercups, with only a few daisies and dandelions present. Sample 2
is therefore considered to be less diverse than sample 1.
Flower Species
Daisy
Dandelion
Buttercup
Total
Table 1: Flowers
Numbers of individuals
Sample 1
Sample 2
300
20
335
49
365
931
1000
1000
1. What two main factors are taken into account when measuring diversity?
2. What is species richness? Which sample above is more “rich”?
3. What is species evenness? Which sample above is more “even”?
4. In this lab we are looking at the different books found in the library. Therefore, we will
use which index (richness or evenness) to determine diversity?
Which would you consider to show greater diversity, a small island with 100 lizards that belong to
5 species or a larger island that has 2500 lizards belonging to 5 species? Both islands have the
same number of species, therefore that number alone cannot properly show biodiversity. For that
reason, diversity is measured in different ways:
Method One:
D = (S-1)/(Log N)
D = diversity – the larger the number, the more diverse
S = number of species
N = total number of individuals in the sample.
Determine the diversity of lizards on the islands and circle the most diverse
Small Island diversity = _____________ Large Island diversity = _____________
Method Two:
Some measures of diversity include a way of counting the number of individuals of each species as well as
the total number of species. One commonly used measure of species diversity that includes proportions
of individuals is represented by the Shannon-Weaver equation, which is:
-sum (pI ln pI)
H = diversity- the larger the number, the more diverse
Pi = relative abundance = ni/N
ni = number of individuals of species “i ”
N= total number of individuals of all species
Small Island Diversity
ni
pi
Species
i
Lizard Species
1
1
(species
“#1”)
22 individuals
2
20
3
25
4
15
5
18
Lizard Species
2
Lizard Species
3
Lizard Species
4
Lizard Species
5
S= 5
Total
number of
species
pi ln pi
ni/N= 22/100
N=100
1.00
Total individuals
ln pi
-
H = sum (Pi ln(Pi))
H=
Large Island Diversity
ni
pi
Species
i
Lizard Species
1
1
(species
“#1”)
635
individuals
2
561
3
664
4
391
5
249
Lizard Species
2
Lizard Species
3
Lizard Species
4
Lizard Species
5
S= 5
Total
number of
species
ln pi
pi ln pi
ni/N=
-
N= 100
H = sum (Pi ln(Pi))
1.00
Total individuals
H=
Determine the H value (diversity) of lizards on the islands and circle the most diverse:
Small Island diversity = _____________ Large Island diversity = _____________
Did both methods produce the same answer?
Which do you feel is more accurate? Why?
Procedure:
You will determine the diversity of books in the library using the S-W Index. In groups you will record the
number of individuals based on the your assigned species (color) of book in the section. Please remember to
look for the predominant color on the spine of the book. Remember that members of the same species may
come in various sizes. Record your data on the table on the next page
Library location:
Spine Color
Black
Number
Spine Color
Yellow
Brown
White
Blue
Red
Green
Purple
Orange
Totals of all
colors:
Number
Library Diversity Location:
Species
i
Black
Brown
Blue
Green
Orange
Purple
Red
White
Yellow
Non-Fiction 500-700
Group 4
Non-Fiction 700-800
Group 5
Non-Fiction 800-900
pi ln pi
ni/N=
4
5
6
7
8
9
N=
Total individuals
Number of
individuals
Non-Fiction 300-500
Group 3
ln pi
3
Total
number of
species
Non-Fiction 000-300
Group 2
pi
2
S= 5
Group 1
ni
1
(species
“#1”)
1.00
-
H = sum (Pi ln(Pi))
H=
H Value
Rank of diversity
(1 being most diverse)