Biodiversity

Biodiversity is defined as the variety of all forms of life, from genes to species, through to the broad scale of ecosystems.

Biological diversity can be quantified in many different ways. 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. However, diversity depends not only on richness, but also on evenness. Evenness compares the similarity of the population size of each of the species present.

A diversity index is a statistic intended to measure the differences among members of an ecosystem consisting of various types of objects. There are different types of diversity indexes such as:

• Simpson's Diversity Index: measures the probability that two individuals randomly selected from a sample will belong to the same species. It is measured by the following formula:

When apllying the formula, the value that we can obtain starts with 1, representing a community of only one specie. The higher the value obtained, represent greater diversity.

To calculate Simpson's Index for a particular area, the area must first be sampled. The number of individuals of each species present in the samples must be noted.

• Shannon's Diversity Index: Is another diversity index used for characterize diversity in a community. It accounts for both abundance and evenness of the species present. The formula for applying this index is: