TerrestrialRealm
T1 - Tropical-subtropical forests biomeBiome
T1.1 - Tropical/Subtropical lowland rainforests
T1.2 - Tropical/Subtropical dry forests and thickets
T1.3 - Tropical/Subtropical montane rainforests
T1.4 - Tropical heath forests
T2 - Temperate-boreal forests and woodlands biomeBiome
T2.1 - Boreal and temperate high montane forests and woodlands
T2.2 - Deciduous temperate forests
T2.3 - Oceanic cool temperate rainforests
T2.4 - Warm temperate laurophyll forests
T2.5 - Temperate pyric humid forests
T2.6 - Temperate pyric sclerophyll forests and woodlands
T3 - Shrublands and shrubby woodlands biomeBiome
T3.1 - Seasonally dry tropical shrublands
T3.2 - Seasonally dry temperate heath and shrublands
T3.3 - Cool temperate heathlands
T3.4 - Young rocky pavements, lava flows and screes
T4 - Savannas and grasslands biomeBiome
T4.1 - Trophic savannas
T4.2 - Pyric tussock savannas
T4.3 - Hummock savannas
T4.4 - Temperate woodlands
T4.5 - Temperate subhumid grasslands
T5 - Deserts and semi-deserts biomeBiome
T5.1 - Semi-desert steppe
T5.2 - Succulent or Thorny deserts and semi-deserts
T5.3 - Sclerophyll hot deserts and semi-deserts
T5.4 - Cool deserts and semi-deserts
T5.5 - Hyper-arid deserts
T6 - Polar/alpine (cryogenic) biomeBiome
T6.1 - Ice sheets, glaciers and perennial snowfields
T6.2 - Polar/alpine cliffs, screes, outcrops and lava flows
T6.3 - Polar tundra and deserts
T6.4 - Temperate alpine grasslands and shrublands
T6.5 - Tropical alpine grasslands and herbfields
T7 - Intensive land-use biomeBiome
T7.1 - Annual croplands
T7.2 - Sown livestock pastures
T7.3 - Plantations
T7.4 - Urban and industrial ecosystems
T7.5 - Derived semi-natural pastures and old fields
SubterraneanRealm
S1 - Subterranean lithic biomeBiome
S1.1 - Aerobic caves
S1.2 - Endolithic systems
S2 - Anthropogenic subterranean voids biomeBiome
S2.1 - Anthropogenic subterranean voids
Subterranean-FreshwaterRealm
SF1 - Subterranean freshwaters biomeBiome
SF1.1 - Underground streams and pools
SF1.2 - Groundwater ecosystems
SF2 - Anthropogenic subterranean freshwaters biomeBiome
SF2.1 - Water pipes and subterranean canals
SF2.2 - Flooded mines and other voids
Subterranean-MarineRealm
SM1 - Subterranean tidal biomeBiome
SM1.1 - Anchialine caves
SM1.2 - Anchialine pools
SM1.3 - Sea caves
Terrestrial-FreshwaterRealm
TF1 - Palustrine wetlands biomeBiome
TF1.1 - Tropical flooded forests and peat forests
TF1.2 - Subtropical/temperate forested wetlands
TF1.3 - Permanent marshes
TF1.4 - Seasonal floodplain marshes
TF1.5 - Episodic arid floodplains
TF1.6 - Boreal, temperate and montane peat bogs
TF1.7 - Boreal and temperate fens
FreshwaterRealm
F1 - Rivers and streams biomeBiome
F1.1 - Permanent upland streams
F1.2 - Permanent lowland rivers
F1.3 - Freeze-thaw rivers and streams
F1.4 - Seasonal upland streams
F1.5 - Seasonal lowland rivers
F1.6 - Episodic arid rivers
F1.7 - Large lowland rivers
F2 - Lakes biomeBiome
F2.1 - Large permanent freshwater lakes
F2.2 - Small permanent freshwater lakes
F2.3 - Seasonal freshwater lakes
F2.4 - Freeze-thaw freshwater lakes
F2.5 - Ephemeral freshwater lakes
F2.6 - Permanent salt and soda lakes
F2.7 - Ephemeral salt lakes
F2.8 - Artesian springs and oases
F2.9 - Geothermal pools and wetlands
F2.10 - Subglacial lakes
F3 - Artificial wetlands biomeBiome
F3.1 - Large reservoirs
F3.2 - Constructed lacustrine wetlands
F3.3 - Rice paddies
F3.4 - Freshwater aquafarms
F3.5 - Canals, ditches and drains
Freshwater-MarineRealm
FM1 - Semi-confined transitional waters biomeBiome
FM1.1 - Deepwater coastal inlets
FM1.2 - Permanently open riverine estuaries and bays
FM1.3 - Intermittently closed and open lakes and lagoons
MarineRealm
M1 - Marine shelf biomeBiome
M1.1 - Seagrass meadows
M1.2 - Kelp forests
M1.3 - Photic coral reefs
M1.4 - Shellfish beds and reefs
M1.5 - Photo-limited marine animal forests
M1.6 - Subtidal rocky reefs
M1.7 - Subtidal sand beds
M1.8 - Subtidal mud plains
M1.9 - Upwelling zones
M1.10 - Rhodolith/Maërl beds
M2 - Pelagic ocean waters biomeBiome
M2.1 - Epipelagic ocean waters
M2.2 - Mesopelagic ocean water
M2.3 - Bathypelagic ocean waters
M2.4 - Abyssopelagic ocean waters
M2.5 - Sea ice
M3 - Deep sea floors biomeBiome
M3.1 - Continental and island slopes
M3.2 - Submarine canyons
M3.3 - Abyssal plains
M3.4 - Seamounts, ridges and plateaus
M3.5 - Deepwater biogenic beds
M3.6 - Hadal trenches and troughs
M3.7 - Chemosynthetic-based-ecosystems (CBE)
M4 - Anthropogenic marine biomeBiome
M4.1 - Submerged artificial structures
M4.2 - Marine aquafarms
Marine-TerrestrialRealm
MT1 - Shorelines biomeBiome
MT1.1 - Rocky Shorelines
MT1.2 - Muddy Shorelines
MT1.3 - Sandy Shorelines
MT1.4 - Boulder and cobble shores
MT2 - Supralittoral coastal biomeBiome
MT2.1 - Coastal shrublands and grasslands
MT2.2 - Large seabird and pinniped colonies
MT3 - Anthropogenic shorelines biomeBiome
MT3.1 - Artificial shorelines
Marine-Freshwater-TerrestrialRealm
MFT1 - Brackish tidal biomeBiome
MFT1.1 - Coastal river deltas
MFT1.2 - Intertidal forests and shrublands
MFT1.3 - Coastal saltmarshes and reedbeds