Question

For shannon weiner index, why do we need natural logarithm ? Explain this formula

Answer 1

The Shannon Weiner index is a diversity index [H] that is commonly used to characterize species diversity in a community. It accounts for both abundance and evenness of the species present.

The function of the natural logarithm, if considered as a real-valued function of a real variable, is the inverse function of the exponential function, leading to the identities.

The formula for calculating Shannon-Weiner diversity index, H is--

H = - pi In pi.

Here, Pi is the proportion of individual numbers of the i species to the total individual number each species in the quadrats.

For an equal distribution - all types in the data set are equally common - the Shannon entropy has the value of the natural logarithm of the Richness H = iN[R], the more unequal the proportional abundances, the smaller is the Shannon entropy. For only one type in the data set, Shannon entropy equals zero. Therefore high Shannon entropy stands for high, low Shannon entropy for low diversity.