Conversion of life zone to ecologically less valuable land cover in Iran

The life zones of Iran were mapped using the Holdridge system based on biotemperature and precipitation maps of Iran. Conversion of each life zone to an ecologically less valuable land use/cover was determined based on comparing the life zones and the current land cover of Iran. Results showed that Iran contains 26 life zones. The most extensive life zone is subtropical desert life zone covering 21.9 % of the area of the country. Periarid class is the largest humidity province (34.2 % of Iran) followed by arid class (24.8 % of Iran). According to the physiognomic types, most area of Iran (35%) is covered by desert life zone followed by scrub (30.4%), steppe (18.7%), forest (10.2%), woodland (5.6%) and tundra (0.14%) life zone. 87 % of woodland, 64 % of forest, 61 % of steppe and 21 % of scrub life zone were converted to less ecologically valuable land covers. Steppe life zone was the life zone with the largest area (37%) being converted to agricultural lands followed by forest (23%) and woodland (22%) life zone. The smallest area (14%) being converted to agricultural lands was the area with the potential of having scrub life zone. The conversion of forest life zone to agricultural lands and moderate rangelands, the conversion of steppe and scrub life zone to agricultural lands and that of woodland life zone to poor rangelands were the largest types of negative conversions. The Holdridge life zone system can be an efficient approach for comparing potential vegetation and actual vegetation