Why would the eveness of species of two types of forests be the same?

Question

Why would the eveness of species of two types of forests be the same?

Answer 1

I'm thinking maybe you are asking... how could the evenness be the same and the diversity different?  Or how could diversity be the same and the evenness different?

Species diversity measurements are made up of two basic things, species RICHNESS and species Evenness.

Imagine the diversity of the following forest, each has 10 species of tree and 100 trees.

Forest one:  has one each of 9 species of tree and the other 91 trees are the 10th species.

Forest two:  There are 10 individuals of each of the 10 species.

Which forest is more diverse?  Some would say the one which has a more EVEN community (forest two).

You could also have a forest community with different species RICHNESS and the same EVENNESS.

For instance, one forest has 10 species and one species has 5 species.  As long as they have the same number of individuals of each species, their evenness would be the same...

It isn't unrealistic to assume that could happen.

Answer 2

I'm not sure what your asking but I can tell you that eveness refers to species composition and the abundance of those species.  Lets say you have 5 species in an ecosystem and all have 15 individules.  In this system, you would have a high eveness.  Conversely, if you had 5 species in this same area and species A had 15 individuals, species B had 4, Species C 3 and so on, you would have low eveness. High eveness can also determine species diversity.  Generally speaking, the higher the species richness and eveness, the greater the diversity.  At a ecological level, there are many reasons why 2 different forests would have the same eveness.  A simple answer would be that they have the same species richness and abundance.  You may also want to look into peilu's J which is an equation for determining species eveness.