Montane ecosystems

Source: Wikipedia, the free encyclopedia.
(Redirected from
Subalpine
)

A subalpine lake in the Cascade Range, Washington, United States

Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial factor in shaping plant community, biodiversity, metabolic processes and ecosystem dynamics for montane ecosystems.[1] Dense montane forests are common at moderate elevations, due to moderate temperatures and high rainfall. At higher elevations, the climate is harsher, with lower temperatures and higher winds, preventing the growth of trees and causing the plant community to transition to montane grasslands and shrublands or alpine tundra. Due to the unique climate conditions of montane ecosystems, they contain increased numbers of endemic species. Montane ecosystems also exhibit variation in ecosystem services, which include carbon storage and water supply.[2]

Life zones

A stand of mountain birch at around 750 m in Trollheimen, typical of Scandinavian subalpine forests

As elevation increases, the

adiabatic cooling of airmasses.[3] In middle latitudes, the change in climate by moving up 100 meters on a mountain is roughly equivalent to moving 80 kilometers (45 miles or 0.75° of latitude) towards the nearest pole.[4] The characteristic flora and fauna in the mountains tend to strongly depend on elevation, because of the change in climate. This dependency causes life zones to form: bands of similar ecosystems at similar elevations.[5]

One of the typical life zones on mountains is the montane forest: at moderate elevations, the rainfall and temperate climate encourages dense forests to grow.

Holdridge defines the climate of montane forest as having a biotemperature of between 6 and 12 °C (43 and 54 °F), where biotemperature is the mean temperature considering temperatures below 0 °C (32 °F) to be 0 °C (32 °F).[5] Above the elevation of the montane forest, the trees thin out in the subalpine zone, become twisted krummholz, and eventually fail to grow. Therefore, montane forests often contain trees with twisted trunks. This phenomenon is observed due to the increase in the wind strength with the elevation. The elevation where trees fail to grow is called the tree line. The biotemperature of the subalpine zone is between 3 and 6 °C (37 and 43 °F).[5]

Above the tree line the ecosystem is called the alpine zone or

montane grassland and shrubland" biome. A region in the Hengduan Mountains adjoining Asia's Tibetan Plateau have been identified as the world's oldest continuous alpine ecosystem with a community of 3000 plant species, some of them continuously co-existing for 30 million years.[7]

Climates with biotemperatures below 1.5 °C (35 °F) tend to consist purely of rock and ice.[5]

Montane forests

Waimea Canyon, Hawaii, is known for its montane vegetation
.

Montane forests occur between the

The lower bound of the montane zone may be a "lower timberline" that separates the montane forest from drier steppe or desert region.[8]

Montane forests differ from lowland forests in the same area.[10] The climate of montane forests is colder than lowland climate at the same latitude, so the montane forests often have species typical of higher-latitude lowland forests.[11] Humans can disturb montane forests through forestry and agriculture.[10] On isolated mountains, montane forests surrounded by treeless dry regions are typical "sky island" ecosystems.[12]

Temperate climate

Montane forests in temperate climate are typically one of

temperate broadleaf and mixed forest, forest types that are well known from Europe and northeastern North America. Montane forests outside Europe tend to be more species-rich, because Europe during the Pleistocene offered smaller-area refugia from the glaciers.[13]

Temperate montane forest in Bavaria, Germany

Montane forests in temperate climate occur in Europe (the

.

Climate change is predicted to affect temperate montane forests. For example, in the Pacific Northwest of North America, climate change may cause "potential reduced snowpack, higher levels of evapotranspiration, increased summer drought" which will negatively affect montane wetlands.[18]

Mediterranean climate

Iranian oak scrub in the Zagros Mountains

Montane forests in

evergreen oak.[citation needed
]

This type of forest is found in the

]

Subtropical and tropical climate

Tropical montane forest at around 2,000 m in Malaysia

In the tropics, montane forests can consist of

coniferous forest. One example of a tropical montane forest is a cloud forest, which gains its moisture from clouds and fog.[20][21][22] Cloud forests often exhibit an abundance of mosses covering the ground and vegetation, in which case they are also referred to as mossy forests. Mossy forests usually develop on the saddles of mountains, where moisture introduced by settling clouds is more effectively retained.[23] Depending on latitude, the lower limit of montane rainforests on large mountains is generally between 1,500 and 2,500 metres (4,900 and 8,200 ft) while the upper limit is usually from 2,400 to 3,300 metres (7,900 to 10,800 ft).[24]

Tropical montane forests might exhibit high sensitivity to climate change.

Global climate models predict reduced cloudiness in the future. Reduction in cloudiness may already be affecting the Monteverde cloud forest in Costa Rica.[27][28]

Subalpine zone

The subalpine zone is the

subalpine fir in western North America.[33]

, Washington, United States

Trees in the subalpine zone often become krummholz, that is, crooked wood, stunted and twisted in form. At tree line, tree seedlings may germinate on the lee side of rocks and grow only as high as the rock provides wind protection. Further growth is more horizontal than vertical, and additional rooting may occur where branches contact the soil. Snow cover may protect krummholz trees during the winter, but branches higher than wind-shelters or snow cover are usually destroyed. Well-established krummholz trees may be several hundred to a thousand years old.[34]

Sierra Nevada of California, is an example of a subalpine meadow.[35]

Example subalpine zones around the world include the French Prealps in Europe, the Sierra Nevada and Rocky Mountain subalpine zones in North America, and subalpine forests in the eastern Himalaya, western Himalaya, and Hengduan mountains of Asia.

Alpine grasslands and tundra

Alpine flora near Cascade Pass

Alpine grasslands and tundra lie above the tree line, in a world of intense radiation, wind, cold, snow, and ice. As a consequence, alpine vegetation is close to the ground and consists mainly of

lichens.[6]
: 280 

Plants have adapted to the harsh alpine environment.

photosynthesize at temperatures as low as −10 °C (14 °F),[38] and the outer fungal layers can absorb more than their own weight in water.[39]

An alpine mire in the Swiss Alps

The adaptations for survival of drying winds and cold may make tundra vegetation seem very hardy, but in some respects the tundra is very fragile. Repeated footsteps often destroy tundra plants, leaving exposed soil to blow away, and recovery may take hundreds of years.[37]

Alpine meadows form where sediments from the weathering of rocks has produced soils well-developed enough to support grasses and sedges. Alpine grasslands are common enough around the world to be categorized as a

endemic plants which evolved in response to the cool, wet climate and abundant sunlight.[citation needed
]

Alpine landscape below Malyovitsa Peak, Rila Mountain, Bulgaria

The most extensive montane grasslands and shrublands occur in the

]

Where conditions are drier, one finds montane grasslands, savannas, and woodlands, like the Ethiopian Highlands, and montane steppes, like the steppes of the Tibetan Plateau.[citation needed]

See also

References

  1. S2CID 4455333
    .
  2. .
  3. ^ Goody, Richard M.; Walker, James C.G. (1972). "Atmospheric Temperatures" (PDF). Atmospheres. Prentice-Hall. Archived (PDF) from the original on 29 July 2016.
  4. ^ Blyth, S.; Groombridge, B.; Lysenko, I.; Miles, L.; Newton, A. (2002). "Mountain Watch" (PDF). UNEP World Conservation Monitoring Centre, Cambridge, UK. p. 15. Archived from the original (PDF) on 11 May 2008.
  5. ^
    S2CID 11733879
    .
  6. ^ .
  7. ^ Stokstad, Erik (30 July 2020). "Many beloved garden flowers originated in this mountain hot spot—the oldest of its kind on Earth". Science | AAAS. Retrieved 1 August 2020.
  8. ^ . Retrieved 9 March 2012.
  9. ^ Rundel, P.W.; D. J. Parsons; D. T. Gordon (1977). "Montane and subalpine vegetation of the Sierra Nevada and Cascade Ranges". In Barbour, M.G.; Major, J. (eds.). Terrestrial vegetation of California. New York, USA: Wiley. pp. 559–599.
  10. ^ a b Nagy, László; Grabherr, Georg (2009). The biology of alpine habitats. Oxford University Press.
  11. . Retrieved 9 March 2012.
  12. . Retrieved 9 March 2012.
  13. .
  14. on 15 February 2006.
  15. .
  16. .
  17. ^ Dawson, John. Forest Vines to Snow Tussocks: The Story of New Zealand Plants. Wellington: Victoria University Press.
  18. PMID 26331850
    .
  19. .
  20. ^ Tracey, J. G. (John Geoffrey) (1982), The Vegetation of the Humid Tropical Region of North Queensland, pp. 34–38
  21. . Retrieved 9 March 2012.
  22. .
  23. ^ Clarke, C.M. (1997). Nepenthes of Borneo. Kota Kinabalu: Natural History Publications (Borneo). p. 29.
  24. JSTOR 176859
    .
  25. , retrieved 20 February 2021
  26. .
  27. .
  28. .
  29. (PDF) on 23 March 2012. Retrieved 11 March 2012. p. 178.
  30. . fig. 1.
  31. ^ "Pinus mugo". Gymnosperm Database. Retrieved 5 February 2024.
  32. ^ McKenzie, Neil (2004). Australian Soils and Landscapes. p. 98.
  33. ^ Gold, W. (28 January 2008). "BIS258 lecture notes" (PDF). University of Washington. Retrieved 15 March 2009.
  34. ^ "Subalpine ecosystem". Rocky Mountain National Park. U.S. National Park Service.
  35. ^ "Tuolumne Meadows and Tioga Road". Yosemite National Park. US National Park Service. Retrieved 5 February 2024.
  36. ^ Public Domain This article incorporates public domain material from Grassland Habitat Group (PDF). Bureau of Land Management. Archived from the original (PDF) on 24 July 2008.
  37. ^ a b Public Domain This article incorporates public domain material from "Alpine Tundra Ecosystem". Rocky Mountain National Park. National Park Service.
  38. JSTOR 40511430
    .
  39. ^ Whitesel, Todd (2006). "Lichens: two lives in one" (PDF). Minnesota Conservation Volunteer.

External links