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  • Topic: Shannon index, Biodiversity, Species richness
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  • Published : December 6, 2012
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Species Diversity Lab

The diversity of species present in an ecosystem can be used as one gauge of the health of an ecosystem. Species richness is a measure of the number of different species present in an ecosystem, while species evenness measures the relative abundance of the various populations present in an ecosystem. In an ecological survey designed to measure species diversity, a wildlife biologist might determine the number of individuals of each species present in an area, then calculate a "diversity index" for the area. Comparison of the diversity index with that of other areas provides insights into the species diversity and the health of the ecosystem. In this activity your "ecosystem" will be the school parking lot or a natural area on a field trip, and the "species" will be the different car models and colors for the parking lot or real species for a field trip. As a class, we will be comparing the species diversity of the student and staff parking lots or of different plots taken on the field trip. The diversity index we will use is the Shannon Diversity Index. After determining the number of each species (or car), in each plot (or parking lot), the Shannon Diversity Index will be calculated separately for the different plots (or student lot and the staff lot). A rich ecosystem with high species diversity has a large value for the Shannon Diversity Index (H'), while an ecosystem with little diversity has a low H'.

pi = H' = –
(equation 1)(equation 2)

ni = number of individuals of species "i"
N = total number of individuals of all species
pi = relative abundance of species "i" (see equation 1)
S = total number of species
H' = The Shannon Diversity Index (see equation 2)

Materials

|2 parking lots full of cars or a natural habitat |

Procedure

1. Prepare a data table. There must be enough space for 20 “species”.

2. Visit a natural area and mark off a plot area (or the school’s parking lot) and collect data as directed in class.

3. Share data with a group that chose a different plot area. Copy their data table for comparison.

Sample Data Table

← Use an entire page in your lab notebook for your data table. There must be enough space for 20 species

Sample Table 1: Data collected for species in the ________portion of ________________. Area=_____m2

Speciesinipiln (pi)pi (ln (pi))
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
totals

Record Your Observations of the Plot Area

Ex: Area of plot, riparian, near freeway, wilderness area, city park, polluted, heavily used, 100 feet away from development, etc. Lots of detail!

Prelab Question—Write out and answer the following questions

1. Identify which habitat (or parking lot) you expect to be the most diverse, and defend your choice. Example: soft bottom riparian area vs concrete channel, area near trail or far away from trail, area under freeway or not, etc.

Data Analysis

1. Determine the value for the Shannon Diversity Index for the data collected by your group. Show all of your work.

2. Tabulate the values calculated by each group for the Shannon Diversity Index.

3. Compare the values for the Shannon Diversity Index.

4. Compare the values of your data table vs. another groups data table.

Postlab Questions—Write out and answer the following questions

1. Identify the parking lot that was the most diverse. Based on your observations during the lab, explain why your prediction in question #1 of the prelab was supported or not supported.

2. List the single most abundant species in each set of data, and write a plausible explanation to explain why these are the most abundant species.

3. Determine the maximum and minimum values for the Shannon Diversity Index in the plot area (or parking lot) you surveyed.

4. If you conducted this lab in a city park, predict whether the Shannon Diversity Index would be high...
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