Simpson’s diversity index (SDI) measures community diversity. Although it’s commonly used to measure biodiversity, it can also be used to gauge diversity differences in populations in schools, communities and other locations. The range is from 0 to 1, where: High scores (close to 1) indicate high diversity.

Community structure means the internal structure of an employment area, town, city, neighbourhood or another urban area. It includes the population and housing, jobs and production, service and leisure time areas, along with transport routes and technical networks, their location and relationships.

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.

It is calculated from the equation: It is estimated as (ni/N). N is total number of individuals in S species. The value of Shannon index usually varies between 1.5 and 3.5 and rarely exceeds 4.5. The value of H’ is related to species richness but is also influenced by the underlying species abundance distribution.

In the Shannon index, p is the proportion (n/N) of individuals of one particular species found (n) divided by the total number of individuals found (N), ln is the natural log, Σ is the sum of the calculations, and s is the number of species.

A community dominated by one or two species is considered to be less diverse than one in which several different species have a similar abundance. Simpson’s Diversity Index is a measure of diversity which takes into account the number of species present, as well as the relative abundance of each species.

two types

The Brillouin index measures the diversity of a collection, as opposed to the Shannon index which measures a sample. Pielou (1975) recommends this index in all situations where a collection is made, sampling was non-random or the full composition of the community is known.

CHAO1 index – appropriate for abundance data – assumes that the number of organisms identified for a taxa has a poisson distribution and corrects for variance. It is useful for data sets skewed toward low-abundance calls, as if often the case with microbes.

Chao1 estimates number of species, whereas Shannon estimates effective number of species.

While alpha diversity is a measure of microbiome diversity applicable to a single sample, beta diversity is a measure of similarity or dissimilarity of two communities.

From Wikipedia, the free encyclopedia. In ecology, alpha diversity (α-diversity) is the mean species diversity in sites or habitats at a local scale. The term was introduced by R. H. Whittaker together with the terms beta diversity (β-diversity) and gamma diversity (γ-diversity).

In ecology, beta diversity (β-diversity or true beta diversity) is the ratio between regional and local species diversity. The term was introduced by R. H. As a result, there are now many defined types of beta diversity. Some use beta diversity to refer to any of several indices related to compositional heterogeneity.

Alpha diversity is the diversity in a single sample site (e.g. human gut) and beta diversity describes the difference in diversity between those sites1 (e.g. different regions of the body).

The number of species measured for the entire biosphere is called omega diversity. In a given area, the measurement of variety of taxa (at the genus and family taxonomical levels) is referred to as taxon or taxic diversity, that when studied at species level called as species diversity.

Alpha = R – Rf – beta (Rm-Rf) R represents the portfolio return. Rf represents the risk-free rate of return. Beta represents the systematic risk of a portfolio. Rm represents the market return, per a benchmark.

Humans depend upon biodiversity for survival, such as for the foods we eat, medicines we use to stay healthy, and materials we wear or use to build our homes. These services are the tangible products or items that we and other species con sume for survival.