The best approach is to fit our data to a geometrical series and

then calculate the slope m or the slope of rank abundance distribution regression.

In this way we analyze if the site is very disturbed or not so much disturbed or

completely undisturbed comparing the slope and the regression of the RAD.

Low slope means that there is more evenness and

so that the side that we are analyzing is undisturbed.

High slope means that the evenness is very low and

in this case the side is disturbed because there is dominance of species.

To avoid the influence of the richness we can use, the evenness of Smith-Wilson.

That's very useful in these cases when we want to analyze the impacts of

biodiversity.

Another way, another meter of species distribution to analyze the impacts

of biodiversity Is the ECDF, the empirical cumulative distribution function,

or the K-dominance curves.

And the last way is a new system, a new graph,

that I want to show you to analyze the impact that is ABC curves.

ABC curves are curves that are based on the distribution of abundances

and biomass.

So we use ABC curve to analyze the effect of impacts of biodiversity,

because biomass grow in a different way with respect to biodiversity

when the site is disturbed or not.

So do you remember from the last lectures that we

started to analyze what is an ECD curve.

So empirical cumulative distribution function curve.

The empirical cumulative distribution function is a powerful graph

to understand what are the impacts, or topogenic impacts on biodiversity.

For instance in this example you will find three curves.

And the highest one is the undisturbed forest, the intermediate one is

a disturbed forest, and the lowest one is an agricultural field.

You see the agricultural field, for instance,

as the intermediate part of the cube that is quite parallel or

more parallel to the epsilon axis if compared to undisturbed forest.

Moreover, the undisturbed forest is the left low part

that is higher than the other two groups.

This means that the number of rare species in the undisturbed forest is higher than

the other two.

Another way to analyze impacts on biodiversity is K-dominance curves.

You see in this example there are two curves, and the highest one means that

the community in that case has more biological diversity, is more diverse,

than the second one.

So the curve that's placed itself on top of the graph is more diverse,

and the curve that is below the others is the lower diverse.

A third interesting way to analyze the affect of anthropogenic impacts

on biodiversity is the Abundance Biomass Curves, the ABC curves.

From these curves you can monitor what are the effects.

In this example you will see three different communities.

One is undisturbed, the second one is moderately disturbed,

the third on is highly disturbed.