The atlas generator is the most powerful feature of QGIS's print composer. It can create a lot of maps automatically based on a template we provide. The underlying concept is very basic--we have to provide a polygon layer with a column which has unique values. The print composer takes that layer, and creates a separate map page for every different value (therefore, feature) it can find in the provided column. Furthermore, it grants access to the current feature it uses for the given page. The real power comes from the QGIS expression builder, which enables us to set cartographic preferences automatically. With this, we can build a template for our atlas and use it to showcase each suitable area in its own map.
First of all, if we would like to create a front page with every suitable area on a single map, we have to create a feature enveloping the polygons from our suitable areas polygon layer. We can create such a polygon with QGIS geoalgorithms | Vector geometry tools ...