I think its a simple question just need some clarification.
If we are doing a complete bird survey of an area after every 15 days (2 times per month), and say in the 1st survey we found 100 individuals of 10 species and in the 2nd we found 150 individuals of 12 species (10 species same like last but different number of individuals in 2nd survey) , what will be the Shannon diversity index for that whole month?
Should we take the maximum number of individuals from both surveys and find Shannon index?
And same in this way if we have data for one year how can we find Shannon Index for one whole year?
Regards
It means for Example for 1st Survey Shannon Index is 2.0 and for 2nd survey of same month it is 2.5 then the Biological diversity for that month will be 2.25. Please correct me if i am wrong.
Say in-case Shannon diversity index for 12 months is like this
J F M A M J J A S O N D
2.0 2.5 2.1 2.2 3.0 2.0 1.0 1.5 2.0 1.5 3.0 2.5
Then what will be the Shannon index for whole year? Should i go for mean?
Say For example if i want to check what is the effect of Annual land-use changes on birds biodiversity of that area? Then?
Just remembering that species diversity should be calculated within groups that may compete for the same niche or habitat, otherwise the results may be distorted.
There is no way in the same same diversity include a bird of prey and Formicariid.
After to evaluate the differential observability of each group of species as William says, and retaining an homogenous observability-rate group (normally excluding raptors, aquatic and cryptic species), my suggestion is to use the two surveys per month as subsamples. That means, that the abundance of each species is the maximal number of individuals between both subsamples. Note that the richness will be the total number of species observed along the whole month. A good idea would be to show the diversity index per month, but if you are interested in to show the variation along the year you can use the range plus the mean and a dispersion measurement. If you are interested in to have only one value of diversity index per year, and if you think that the diversity and composition is relatively constant along the year, a possibility is to proceed with all the 24 measurements as subsumples as mentioned above.
Thanks a lot Alvaro Garitano-Zavala....You explained it very nicely now i am clear about it :)
Thanks William and Justice.
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