The vegetation zones coverage:
Target regions should be distributed across all the major vegetation zones, or zonobiomes (sensu Walter 1985; Richter 2001),
- from tropical to polar latitudes to cover tropical mountains with a diurnal humid climate (Zonobiome I);
- tropical mountains with an annual temperature and precipitation periodicity (Zb. II);
- high desert areas of the tropics and subtropics (Zb. III);
- Mediterranean mountains (Zb. IV);
- mountains in the warm-temperate humid vegetation zone (Zb. V);
- temperate mountains (Zb. VI); temperate dry mountains (Zb. VII);
- boreal mountains (Zb. VIII);
- and polar/arctic/antarctic mountains (Zb. IX).
Further, major transition zones such as subpolar, or transitions from Zb. I to Zb. II, may be considered.
Currently, most sites are concentrated in Europe, where only mediterranean, temperate, boreal, sub-polar mountains are found.