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Biome (バイオーム)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Proposed by Clements (1916) and used by Clements & Shelford (after 1932)
A major regional ecological community of organisms usually defined by the botanical habitat in which they occur and determined by interaction of the substrate, climate, and flora. The term is often limited to denote terrestrial habitats, for example, tundra, coniferous forest, and grassland. Oceans may be considered a single biome, the marine biome, although sometimes this is subdivided, for example, coral reef biome. There is no sharp distinction between adjacent biomes. (Hale & Margham 1991)
A major regional ecosystem, characterized by its distinctive vegetation, a particular plant formation, and associated animals, microbes, and physical environment (life zone) (e.g., grassland, tundra, savanna). A biome is a subdivision of a continent on the basis of major differences in the life form of the vegetation, where life-forms reflect the regional climates and soils. (Dunster & Dunster 1996)

Translation into Japanese

'Biome' is transtrated 'Seibutsu-gunkei (生物群系)', or 'Shokubutsu-gunkei (植物群系)' into Japanese. The phonological translation is also used.

flora (フローラ)
physiognomy (相観)

[The World's Biomes]

Biome type

Table. The characteristics of biome. (Mackenzie et al. 2001)

biome net primary production biomass ecosystem environment
TundraLowLowLowlow (< 250 mm), mainly as snow
DesertDepending on rainfallLowHighly variableExtremely low (so-called arid regions)
GrasslandHighLowIntermediate between that of deserts and forests

[ peat 泥炭 | wetland 湿原 ][ IGRF (偏角計算)]

Tundra (ツンドラ)

Etymology: Lappish language tunturia that means land without trees

Primary regions

Arctic tundra
Distribution: circumpolar, with southern limits roughly following the mean summer position of the arctic cold fronts

extends over ≈ 5% of the terrestrial ecosystems

Climate: winter temperatures < -10°C

short growing season for plants with cool temperatures < 10°C
precipitation 100-200 mm (precipitation is greater than potential evapotranspiration)
night under the midnight sun in summer at latitudes > 66°

microsite → significant role influencing plant distribution
deep snow pack on leeward versus barren windward
north-versus south-facing slopes
drainage versus slope
soil water drainage can result in ponding

permafrost → polygon (methane emission)

ice wedge (氷楔)
periglacial landforms (周氷河地形)
[ baidzharakh (バイジャラーヒ) | pingo (ピンゴ) | yedoma (エドマ) | palsa (パルサ)]

plant lists

Fig. Arctic vegetation (From Bonanza LTER webpage)

Turlough: areas seasonally flooded by karst groundwater with sufficient frequency and duration to produce wetland characteristics. They generally flood in winter and are dry in summer and fill and empty through underground passages (used in western Ireland)


Where the tundra begins ...
Although small pockets of trees exist beyond this point (= the northern edge of the Brooks Range), the continuous forest ends. It is not the deep cold that prevents trees growing in the far norht. In fact, the coldest temperatures have been recorded in the forest, not the tundra. It is not the wind, the permafrost, or the lack of water, although they play a part. the main reason that trees do not grow north of here is that there are only a few days each year warm enough for photosynthesis to occur. To survive here, plants must work at conserving energy. Production and maintaining large woody stems or trunks is a luxury tundra plants cannot afford.

... and the Forest Ends

Species richness: high (depending on the scale)
Stunted growth
The trees here might look young, but you may be surprised to discover that some of them are over 200 years old. Botanists aged a 10-inch-diameter (25 cm) white sprucee growing here and determined the seedling took root in 1720 - twenty years before the Russians first came to Alaska.
Representative species
Betula nana, darf birch: Compared to their southern relatives, dwarf birch huddle close to the ground for protection against the wind and cold. In the fall, they paint the tundra with color, from salmon pink to burgundy red.
Salix arctica, arctic willow: provides food for many tundra denizens. Voles and hares gnaw the bark, caribou and muskoxen brose on the twigs, and ptarmigan nip off the buds.
Vaccinium uliginosum, alpine blueberry
Arctostaphylos alpina, alpine bearberry: is inconspicuous until late summer, when the leaves turn a brilliant scarlet. Deep purple berries are a favorite with bears and ptarmigan, but humans find them rather bland.

Alpine tundra
not defined simply by precipitation and temperature
fragmented distribution along mountain ranges (distribution is latitude dependent, being higher in equatorial regions)
extensive, extending over ≈ 3% of the terrestrial ecosystems
80% of alpine tundra in the northern hemisphere Vegetation
H/G (woody) and Perennials + long-day plant
high species diversity and endemism
Comparisons of arctic and alpine tundra environments
Permafrost: yes vs no
Diurnal temperature fluctuation: low vs high
Solar radiation: low vs high

[warming experiment]

Grassland (草原)

s.s. vegetation dominated by grasses (Poaceae)
s.l. s.s. + sedge and rush with legumes and other herbs
The major grassland types are: steppe and savanna

Steppe (ステップ)

Dry, grassy plain in semi-arid or continental climate
• cold or temperate steppe: eastern Europe - central Asia
• subtropical steppe - Mediterranean-like regions in Europe

Savanna (savannah, サバンナ)

mixed woodland-grassland, i.e. grassy woodland

wildfires - frequent
grazing - intensive

Semi-natural grassland (半自然草原)

disturbances, represented by wildfire, maintain the grasslands

Grasslands in Japan

mostly maintained by human disturbances, such as prescribed fire, bush cutting and grazing

Desert (砂漠)

Low precipitation with variable temperatures → low productivity and biomass

life form

Desert in Japan
Ex. volcanic desert (火山荒原, 火山砂漠) + human immpact (e.g., Erimo Cape 襟裳岬, Sarobetsu mire サロベツ原野)