The Shannon coefficient. How to calculate the number of aphids in points?

Taking into account the biomass of aphids only, it is impossible, because The Shannon index for biomass assumes knowledge of the total biomass of all species, and you don't have it.
By number, in Instances per plant, you can use the standard formula
H = - SUM(p(i)*log2(p(i))),

where p (i) = n(i)/N

p (i) is the relative abundance of the i-th species on the plant
n (i) is the number of instances of the i-th species on the plant
N is the total number of all species on the plant, i.e. the sum of all n(i)

If you have n(i) as the average values, then at least the standard deviation and 95% confidence interval will not be superfluous.

I don't know how to link scores to the Shannon index, but statistical analysis uses rank criteria to compare samples by score.

Although, if your number was taken into account in different ways, for aphids in one way, and for others in another way, and you want to calculate the Shannon index, then you can normalize the number of phytophages, taking into account the knowledge of what number the points and percentages for aphids correspond to. As a result, you will get uniform population estimates in points and percentages. You substitute them in the Shannon formula and get an index score based on points or percentages (which is almost the same if the percentages are not accurate, but reflect the same points or ranks, but in%).

Why do I think this will work?
Because for the Shannon Index, the absolute size of the population is not important, but only the relative one is important, therefore, any value that reflects the relative number will do.

Alternatively, convert aphid scores and percentages to numbers and calculate them using the formula from the previous topic.

The values of H for any of these methods should be approximately equal.
And finally, this index characterizes not the aphid, but the test site.
"For aphids" it doesn't make sense.

If you want to compare sites specifically by aphids (by aphid distribution), without phytophages, then it is better not to use the Shannon Index, but to compare samples by the chi-square criterion, for example.

This post was edited by Seneka-08.08.2013 17: 16