What does the Shannon diversity index mean?
Methods: The Shannon diversity index (H) is another index that is commonly used to characterize species diversity in a community. Like Simpson's index, Shannon's index accounts for both abundance and evenness of the species present. Equitability assumes a value between 0 and 1 with 1 being complete evenness.
The most common measures of biodiversity are species richness, Simpson's index and Shannon-Wiener index. Species Richness. This is the simplest of all the measures of species diversity. All you do is count of the number of species found in a community (e.g., the number of the species found on a biofilm plate).
- Introduction: A diversity index is a mathematical measure of species diversity in a community. Like Simpson's index, Shannon's index accounts for both abundance and evenness of the species present.
- Species abundance is the number of individuals per species, and relative abundance refers to the evenness of distribution of individuals among species in a community.
- The two main factors taken into account when measuring diversity are richness and evenness. Richness is a measure of the number of different kinds of organisms present in a particular area. For example, species richness is the number of different species present.
A diversity index is a quantitative measure that reflects how many different types (such as species) there are in a dataset (a community), and simultaneously takes into account how evenly the basic entities (such as individuals) are distributed among those types.
- Species diversity is the number of different species that are represented in a given community (a dataset). Species diversity consists of three components: species richness, taxonomic or phylogenetic diversity and species evenness.
- The 'relative abundance' of an isotope means the percentage of that particular isotope that occurs in nature. Most elements are made up of a mixture of isotopes. The sum of the percentages of the specific isotopes must add up to 100%. The relative atomic mass is the weighted average of the isotopic masses.
- The relative abundance depends on the relative stability of the isotope. The relative abundances for the three carbon isotopes are carbon-12 is 98.9%, carbon-13 is 1.1% and carbon-14 less than .001%. The isotopes contribute to the average atomic mass based on their abundance.
Updated: 16th October 2019