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How to calculate species abundance and diversity 
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#1
Nov311, 06:07 PM

P: 19

1. The problem statement, all variables and given/known data
This is the sample population taken along a 5m transect: ants:9 grasshoppers:1 pill bugs:4 spiders:1 2. Relevant equations What formulas would i use to calculate the species abundance and diversity? 3. 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. 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution 


#2
Nov311, 06:50 PM

HW Helper
P: 6,187

Hi blicker!
Can it be that your formula is actually: where "ln" is the natural logarithm (and also a button on your calculator), and where n_{i} is the number of individuals of species i? See: http://en.wikipedia.org/wiki/Shannon_index 


#3
Nov311, 07:07 PM

P: 19

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
Nov311, 07:18 PM

HW Helper
P: 6,187

How to calculate species abundance and diversity
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
Nov311, 07:26 PM

P: 19

so would the equation for ants look like this:
(9/15)In(9/15) 


#6
Nov311, 07:35 PM

HW Helper
P: 6,187

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
Nov311, 07:44 PM

P: 19

well thanks for your help anyway.



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