select the species by their geographic range of distribution,
you should select the requested one or more regions of the list.
The signs change their colors and the respective regions on the
map become darker, which is a sign that the selection has been
made. The choice is confirmed by clicking the Characteristics
button. The selection shall include all the species, which occur
in least one of the chosen regions.
If you wish to change the selection, you should first click on
the Clear button, and then make a new choice.