How to calculate species abundance and diversity

  • Thread starter blicker
  • Start date
  • #1
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Homework Statement


This is the sample population taken along a 5m transect:
ants:9
grasshoppers:1
pill bugs:4
spiders:1


Homework Equations


What formulas would i use to calculate the species abundance and diversity?


The Attempt at a Solution


I only know this formula H'=-[itex]\Sigma[/itex] (n[itex]_{}i[/itex]/N)xIn(n[itex]_{}i[/itex]/N) and i dont know what to do with this formula.

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
I like Serena
Homework Helper
6,577
176
Hi blicker! :smile:

Can it be that your formula is actually:
3799228b95da61aa2eca76e4132f0aa2.png

where "ln" is the natural logarithm (and also a button on your calculator), and where ni is the number of individuals of species i?

See: http://en.wikipedia.org/wiki/Shannon_index
 
  • #3
19
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yes thats it! but i dont know what numbers go where or how to calculate it. like would i include the sigma symbol and the letters above and below it?
 
  • #4
I like Serena
Homework Helper
6,577
176
The sigma symbol indicates that you have to sum.
So:
[tex]H'=-\sum_{i=1}^S {n_i \over N} \ln {n_i \over N} = -({n_1 \over N} \ln {n_1 \over N} + {n_2 \over N} \ln {n_2 \over N} + {n_3 \over N} \ln {n_3 \over N} + {n_4 \over N} \ln {n_4 \over N})[/tex]

From wiki:
* ni The number of individuals in species i; the abundance of species i.
* S The number of species. Also called species richness.
* N The total number of all individuals
* pi The relative abundance of each species, calculated as the proportion of individuals of a given species to the total number of individuals in the community: [itex]n_i\over N[/itex]
 
  • #5
19
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so would the equation for ants look like this:
-(9/15)In(9/15)
 
  • #6
I like Serena
Homework Helper
6,577
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so would the equation for ants look like this:
-(9/15)In(9/15)
Well, Shannon's index specifies to sum all the terms.
So what you mention is only part of H'.

Btw, it is [itex]ln[/itex] ("logarithmus naturalis").


But I can't really tell you what your problem asks.
I'm not studying whatever science you're studying - I'm a mathematician.

I did find this article about diversity: http://en.wikipedia.org/wiki/Diversity_Index
And apparently [itex]n_i[/itex] is the "species abundance".
Furthermore [itex]p_i={n_i \over N}[/itex] is the "relative species abundance".
 
  • #7
19
0
well thanks for your help anyway.
 

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