This is the area equivalent to compare points. You select or generate two areas and either a taxa, a lifeform or a species list on which to base the comparison. The areas can either be defined on the fly using any of the area generation options, or the two areas can be defined as those contained within the polygons defining a contextual layer and the area outside those polygons. For example, you could compare the bird species within Bush Heritage areas and outside those areas. We would like to be able to add the ability of comparing one or more classes within a contextual layer to all other classes in a contextual layer. 

The output from this tool is a table with two rows (the IN area and the OUT area) and three columns – the area in square kilometers of each area, the number of species in the area and the number of occurrence records in the area. This table is automatically exported as a CSV file.

More information can be found at Tools | Compare areas