To select the range of the elevation, you should choose the lower
and upper boundary, among the given indicators and to confirm
the choice by clicking the Characteristics button. The selection
will include all the species, occurring in the selected range.
If you wish to change the selection, you should first click on
the Clear button, and then make a new choice.
Attention: You may only choose successive values (for example
you may not choose only the value 500 and at the same time only
the value 2000 - the programme will select the range between them).