Similar term(s): drylands.
Dryland systems are
ecosystems characterised by a lack of
water. They include cultivated lands, scrublands, shrublands, grasslands,
savannas, semi-deserts and true deserts.
The lack of water constrains the production of crops, forage, wood, and other
Four dryland subtypes are widely recognized: dry sub-humid,
semiarid, arid, and
hyperarid, showing an increasing level of aridity or moisture
Source: GreenFacts based on Millennium Ecosystem Assessment
Drylands refer to land areas where the mean annual precipitation (P) is less
than two thirds of potential evapotranspiration (PET = potential evaporation
from soil plus transpiration by plants), excluding polar regions and some high
mountain areas which meet this criterion but have completely different
Hyperarid areas, also referred to as true deserts, have a P/PET ratio of less
Arid areas have a P/PET ratio of 0.05 to 0.20.
Semiarid areas have a P/PET ratio of 0.20 to 0.50.
Dry sub-humid areas have a P/PET ratio of 0.50 to 0.65.
Source: GreenFacts, based on CBD
Dry and Sub-humid Lands Biodiversity
To read about this term in context:
GreenFacts Summary on Desertification:
Español: Tierras secas
Français: Zones sèches
Nederlands: Droge gebieden