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(Upload on January 4 2014) [ 日本語 | English ]

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.

Biome type


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

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

[ periglacial landforms 周氷河地形| peat 泥炭 | wetland 湿原 ]

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°
Vegetation
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
plant lists

Arctic
Fig. Arctic vegetation (From Bonanza LTER webpage)

Alaska

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.

索引
Alpine tundra
distribution
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)


Desert (砂漠)


Low precipitation with variable temperatures → low productivity and biomass

photosynthesis
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)

References


  • Nelson FE, Outcalt SI, Goodwin CW, Hinkel KM. 1985. Diurnal thermal regime in a peat-covered palsa, Toolik Lake, Alaska. Arctic 38: 310-315
  • Tsuyuzaki S, Nakayama T, Kuniyoshi S, Fukuda M. 2001. Methane flux and vegetation types in grassy marshlands near Kolyma River, northern Siberia. Soil Biology and Biochemistry 33: 1419-1423
  • Tsuyuzaki S, Ishizaki T, Sato T. 1999. Vegetation structure in gullies developed by the melting of ice wedges along Kolyma River, northeastern Siberia. Ecological Research 14: 385-391
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