For example, if you got a Shannon index of 2.85, this number can be converted into ENS that is exp(2.85) = 17. Even then I doubt, whether the formula high diversity = good, low diversity = bad is always true. If value ranges towards 1. Shannon’s diversity index will serve well for the comparisons between sites or samples after standardization of abundance via rarefaction. Can we now focus on something more relevant?Basically the index is a reflection of the congenial/stressful condition where the community is thriving. 2012). If E is close to 1.0, this means that equitability is higher (all species in the community are represented by a similar # of individuals) and therefore H'obs can be considered higher.You should also pay attention to the type of logarithms (ln, log10, log2) used before making any comparisons.The Shannon-Wiener diversity index (H) is a measure of diversity that combines species richness (the number of species in a given area) and their relative abundances. These informatics can provide a substantial amount of descriptive information about samples if used correctly.Shannon Wiener Diversity Index: Will it be useful to calculate the diversity index and evenness of gastropod species. It tells the level of diversity in that particular area, i.e. please help?
The diversity index family has been proposed at the end of 70'; do not be afraid to use it, even if it is old it does not mean it is rubbish! Version 7.
The Shannon equitability index is simply the Shannon diversity index divided by the maximum diversity \( E_{H} = \frac{H}{\log(k)} \) This normalizes the Shannon diversity index to a value between 0 and 1. An example of application you may find it in my profile in a rather old paper "structural analysis of phytoplancton communities...."Shannon-Wiener index is the most widely index which used in marine biodiversity. My thanks to Alexis for setting us aright. You then need to go back and look at your data to see if the difference is due to greater richness, evenness, or both.Instead of the S-W index, the diversity index family A, (Patil & Taillie, 1976, 1979), which is easy to calculate and to whom all diversity indices belong, is likely to be preferred for its desirable properties, in particular for the possibility of drawing diversity profiles which allow a continuum of analysis between the two extremes of species richness (species count) and evenness (Simpson's index). He is doing research work related to this aspect. is there any graduation to help any person interpret the result? Could anyone explain the difference or suggest a good reading? Do you see gradual, slow decrease in abundance, or are there a few abundant and many rare species, or just a handful of common ones? In this respect, the diversity index family A, (Patil & Taillie, 1976, 1979), easy to calculate and to whom all diversity indices belong, is likely to be preferred for its desirable properties, in particular for the possibility of drawing diversity spectra profiles which allow a continuum of analysis between the two extremes of species richness (species count) and evenness (Simpson's index). Furthermore, the Shannon-Wiener is usually used alongside the Simpson's index, which is a measure of dominance, and high dominance would indicate low diversity. Unlike the Shannon-Wiener, the Simpson's index can stand on its own.As Alex Baumel says above Jos (2006) points out that the S-W index is an entropy and in order to calculate the number of equally common coral species you would take the exponent of the S-W index figure you calculated (2.85) which equals 17 equally common species of corals.Ateneo School of Medicine and Public Health (ASMPH)Shannon-Wiener index, along with Simpson index, has been widely used in the ecological literature as a quantitative measure reflecting the number of different types of species existing in a dataset, and concurrently takes into account the how evenly distributed the individuals are among those types. 2006). However, SW is an alpha diversity measure. We have been discussing about which diversity index was the best for at least three generations of scientists.
Diversity indices lack a probabilistic basis, and are (calculated) not sampled from a known distribution and it is impossible to assign a probability value to them, and consequently there is no way to evaluate the statistical and biological differences between two communities with any H’ values (Shannon’s diversity).