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Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily
HOME > Lecture catalog / Research summary > Glossary > Biome
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)
'Biome' is transtrated 'Seibutsu-gunkei (生物群系)', or 'Shokubutsu-gunkei (植物群系)' into Japanese. The phonological translation is also used.
Table. The characteristics of biome. (Mackenzie et al. 2001)
| biome | net primary production | biomass | ecosystem | environment |
|---|---|---|---|---|
| Temperature | Precipitation | |||
| Tundra | Low | Low | Low | low (< 250 mm), mainly as snow |
| Desert | Depending on rainfall | Low | Highly variable | Extremely low (so-called arid regions) |
| Grassland | High | Low | Intermediate between that of deserts and forests | |
| Forest | High | High | Various | High |
[ periglacial landforms 周氷河地形| peat 泥炭 | wetland 湿原 ]
Etymology: Lappish language tunturia that means land without trees
Primary regionsArctic tundradistributioncircumpolar, 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
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AlaskaWhere 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) Alpine tundradistributionnot 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 |
Low precipitation with variable temperatures → low productivity and biomass
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)
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