Download Biodiversity lab

Biodiversity Tests Using the
Simpson’s Diversity Index
Reference: Molnar, W. Laboratory Investigations for AP Environmental Science. 2005
Introduction:
Ecologists often use biodiversity measurements to determine the health of an
ecosystem. A declining biodiversity indicates a declining ecosystem and can indicate that the
ecosystem is or was undergoing some environmental stress.
There are a great number of ways biodiversity is calculated. One of the most common
and easiest methods is the Simpson’s Diversity Index. This method calculates not only the
number of species represented in a given habitat but also how well each species is
represented; therefore, the method takes into account much more than just species richness.
The Simpson’s Diversity value (D) ranges from no diversity at 0.0 to a maximum diversity at
1.0. These values have no real meaning themselves but merely are used as a means of
comparison for different habitats or the same habitat at different times. A large D value
indicates that if you were to go out and collect two organisms from a habitat the odds would
be that the two organisms would be different species.
Example Calculation of Simpson’s Diversity Index:
s
ni
i=1
N
D=1–Σ (
Where
)2
s = the number of morphotypes (species)
i = a given morphotype
ni = the number of individuals in morphotype i
N = the total number of individuals collected (for all morphotypes)
Say:
Community A
Species 1
1000
Species 2
100
Species 3
100
Community B
Species 1 400
Species 2 400
Species 3 400
For Community A:
For Community B:
s=3
n1 = 1000
n2 = 100
n3 = 100
N = 1200
DA = 1 – [(1000/1200)2 + (100/1200)2
+ (100/1200)2]
s=3
n1 = 400
n2 = 400
n3 = 400
N = 1200
DB = 1 - [(400/1200)2 + (400/1200)2
+ (400/1200)2]
DA = 0.292
DB = 0.667
Prelab Question:
Use the Simpson’s diversity index to determine which of the following three communities of
100 individuals is most diverse. Community 1 contains 10 species, with 91 individuals of the
first species, and 1 individual of each of the remaining species. Community 2 contains only 5
species, with 20 individuals of each. Community 3 contains 10 species, with 18 individuals
from 2 of the species and 8 individuals from the remaining 8 species.
Hypotheses: We will investigate the biodiversity of both plants and animals in 8 locations on
campus: Prairie, Wooded Area, Lawn, Pond Edge, Bioretention Cell 1, Bioretention Cell 2,
Bioretention Cell 3, and a Parking Lot Island.
Which location do you believe will contain the highest biodiversity in plants? Why?
Which location do you believe will contain the highest biodiversity in animals? Why?
What do you believe will be the relationship between plant biodiversity and animal
biodiversity? Why?
Part 1: Animal Bi odiversi ty
Locations to be Tested: Prairie, Wooded Area, Lawn, Pond Edge, Bioretention Cell 1,
Bioretention Cell 2, Bioretention Cell 3, Parking Lot Island
Sticky Trap Setting Procedure:
In the lab: Using a Sharpie® put your name and location at the top of the 3 sticky traps given
to you. The top part is the yellow strip at the top with no backing. If the sticky traps are not
hole punched, hole punch the middle top portion of the sticky trap so you can hang the trap
with string if you choose to do so.
In the field: Go to your location site and place the sticky traps in order within your given
location. Place your sticky trap on the ground or secure the trap onto a stick, a wall, a fence, a
plant, a rock, etc., 0 to 3 feet from the ground. After setting each trap, remove the wax paper
from the trap. Return to the site after at least 24 hours to collect the traps.
Sticky Trap Collection Procedure:
Once 24 hours has elapsed return to the sticky traps to observe any activity that has occurred.
Collect the traps and observe the number of different morphotypes present on each trap.
Compare your morphotypes with those found in the same location so you and another group
in the same location don’t count the same morphotype twice.
Species found by you from the sticky traps.
Individual Animal Data
Description of Morphotype
ID of Species?
Number of that
species represented
Animal species found by all the members sampling at your location from the sticky traps.
What was your location?
Location Animal Data
Description of Morphotype
ID of Species?
Number of that
species represented
Refer to your location data and calculate your location’s Simpson’s Diversity Index below.
2
Part 2: Plant Biodiversity
Construct a 1 m quadrat around the sticky trap you analyzed. Within this square meter count
the morphotypes of plants that are found in your quadrat. Record this data below.
Individual Plant Data
Number of that
Description of Morphotype
ID of Species?
species represented
Plant species found by all the members sampling at your location.
What was your location?
Location Plant Data
Description of Morphotype
ID of Species?
Number of that
species represented
Refer to your location data and calculate your location’s Simpson’s Diversity Index below.
Questions & Analysis:
1. Fill out the table below.
Location
Animal Simpson’s
Biodiversity Index
Plant Simpson’s
Biodiversity Index
Prairie
Wooded Area
Lawn
Pond Edge
Bioretention Cell 1
Bioretention Cell 2
Bioretention Cell 3
Parking Lot Island
2. Use the computer to generate a graph of the relationship between plant biodiversity index
and animal biodiversity index. Make sure to attach this graph to your lab write-up when you
turn it in.
3. Describe the general relationship between plant biodiversity index and animal biodiversity
index. Why does this relationship exist?
4. How do the abiotic factors seem to affect the number of species?
5. Determine the differences in the Index values from one location to another.
a. Describe what is different between the habitats.
b. How do you think the moisture, temperature, and any other biotic or abiotic factors
influenced your results?
6. Design an experiment by which you could evaluate the effect of an invasive plant species,
such as purple loosestrife, on songbird diversity, using the Shannon-Weiner Diversity Index.