Question

If there is high species evenness in a community what does that mean?

Answer 1

Answer:- Species evenness means the closeness of each species in a given environment in number or it can also be defined as the frequencies similarity of the different units that makes up a population or a sample.

For instance if I assume that a community that has 10 species and where 99% of individuals belong to one species is considered to be less diverse than a community having 10 species and there is equal repartition of the individuals between the species. Eveness can also be defined as the difference in the distribution of the total abundance between the different species in a community .The highest eveness value of a community will be achieved in case where all species have the same abundance while the lowest eveness value of a community will be achieved where most of the individual belong to one species.

In mathematical term species eveness can also be defined as a diversity index, which is a measure of biodiversity that quantifies how equal the community is numerically. For example if a community has 25 deer and 100 elephants then community cannot be counted as even. But in case there are 25 deer and 28 elephants then the community can be called even.

Pielou's evenness index is used to represent the eveness of a community:

Where is the number which is derived from the Shannon diversity index and is the maximum possible value of (if every species was equally likely), equal to:

J' is constrained between 0 and 1.

The lesser is the evenness in communities between the species , the lower J' is and vice versa. S represents total number of species.