About Lesson
Biodiversity indexing
- It is the process of identifying biodata and mapping their distributions to understand the process of evolution and speciation.
- A Biodiversity Index gives scientists a concrete, uniform way to talk about and compare the biodiversity of different areas.
- Diversity indices are numerical expressions of the quantity of diversity observed within a living system.
- The most popular diversity indices include:
a) Shannon-Wiener (or Shannon-Weaver) method:
b) Simpson’s index method:
A. Shannon-Weiner (or Shannon-Weaver) method:
H’ = – £Pi x lnPi
Where,
H’: – Measure of diversity
Pi: – Proportion of ith species in landscape elements.
B. Simpson’s index
S = 1/ £Pi2
|
Species |
No. of individual |
Pi |
lnPi |
Pi x lnPi |
|
1 |
10 |
0.2 |
-1.609 |
0.3218 |
|
2 |
10 |
0.2 |
-1.609 |
0.3218 |
|
3 |
10 |
0.2 |
-1.609 |
0.3218 |
|
4 |
10 |
0.2 |
-1.609 |
0.3218 |
|
5 |
10 |
0.2 |
-1.609 |
0.3218 |
|
Total |
50 |
£Pi2 = 0.2 |
|
£ Pi x lnPi = -1.609 |
Therefore,
Shannon-Weiner index (H’) = – £Pi x lnPi = 1.609
Simpson Index (S) = 1/ £Pi2 = 1/0.2 = 5