Biodiversity Part II
The National Institute for Mathematical and Biological Synthesis
Dealing with Large Data Sets
 Oftentimes you are working with large data sets that
require analyses using special tools.
 We are going to work with a data set that spans several
years to see if we can say something about the
biodiversity of salamanders in the Great Smoky
Mountains National Park.
 We are going to use Microsoft Excel to make calculations
using more data than we used in part I.
First lets take a look at the data:
Data explanation:
 The data is arranged in an excel spreadsheet for two
sites in the GSMNP. The first column, A, is from the Pig
Pen site and the E column is from the second site, the
Lower Dorsey. The names are salamander species in the
columns.
 Column B and column F give the number of individuals
of each species counted for the year 2000, with the
column name denoted n.
We have this data over several
years.
 We can ask many questions about how the biodiversity
of salamander populations have changed over the years
in the GSMNP.
 We can look at Simpsons Index and compare the two
sites for each year and we can also see if the
biodiversity is changing over the course of several years.
 Click here to download the data
Now that you have the data:
 Lets try and calculate D for the first year at the Pig Pen
Site.
In excel we can use the formula bar to
calculate our numerator and then drag the
Formula down the column to do the calculation
for each species.
1. Type in = in cell C6
2. Then type in the cell B6(B6-1)
3. This will give you the calculation for
53(53-1), which is n(n-1) for your first
observation.
4. Next use your mouse to grab the right
corner of the cell and drag the cursor down
to your last species.
5. Go to the next slide to see if your data looks
the same
Now let’s add all of the
numbers in column C to
get the Σn(n-1), which is
the numerator for D

This is the total for the numerator of
D
Next lets calculate the
denominator

This is N for the N(N-1) in the denominator of SID
In excel find a new cell and calculate N(N-1) using
the formula we used in calculating the denominator
 You should get 6780 cell B21 below.
 Now lets put it all together to calculate SID for the Pig
Pen site, your data should look like this
In cell B22 type in the formula
You want excel to calculate
Remember SID= 1-Σn(n-1)/N(N-1)
Thus you will need to type in:
1. =
2. (C20/B21)
3. Hit Enter
4. You should get a SID of 0.959
On your own or in a group
 Calculate SID for the Lower Dorsey site
 You can do this for each site for every year in the data
set
 Can you see any changes in salamander diversity
between the sites or over the course of several years?
 What can you say about the salamander population in
the GSMNP?