Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation , with an associated harsh climate . As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, and alpine tundra merges with polar tundra .
25-691: The North Northumberland Coastal Plain is a major natural region that lies on England 's northeasternmost stretch of coastline on the North Sea . To the west lie the Cheviot Fringe , the Northumberland Sandstone Hills and Mid Northumberland ; to the south it is continued by the South East Northumberland Coastal Plain . The North Northumberland Coastal Plain lies along the coast of the county of Northumberland and
50-675: A few inches tall, with weak root systems. Other common plant life-forms include prostrate shrubs ; tussock -forming graminoids ; cushion plants ; and cryptogams , such as bryophytes and lichens . Relative to lower elevation areas in the same region, alpine regions have a high rate of endemism and a high diversity of plant species. This taxonomic diversity can be attributed to geographical isolation , climate changes , glaciation , microhabitat differentiation, and different histories of migration or evolution or both. These phenomena contribute to plant diversity by introducing new flora and favoring adaptations , both of new species and
75-450: A few yards of each other, depending on topography, substrate, and climate. Alpine vegetation generally occurs in a mosaic of small patches with widely differing environmental conditions. Vegetation types vary from cushion and rosette plants on the ridges and in the rock crannies; to herbaceous and grassy vegetation along the slopes; dwarf shrubs with grasses and forbs below the melting snowdrifts; and sedges, grasses, low shrubs, and mosses in
100-633: A mountain is roughly equivalent to moving 80 kilometers (45 miles or 0.75° of latitude) towards the pole. This relationship is only approximate, however, since local factors such as proximity to oceans can drastically modify the climate. In the alpine tundra, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowpack, or associated lack of available moisture). Typical high-elevation growing seasons range from 45 to 90 days, with average summer temperatures near 10 °C (50 °F). Growing season temperatures frequently fall below freezing, and frost occurs throughout
125-645: A quarter of the NCA lies within the Northumberland Coast Area of Outstanding Natural Beauty and also within the North Northumberland Heritage Coast. The region contains four Special Areas of Conservation - Berwickshire and North Northumberland Coast SAC; Newham Fen SAC; River Tweed SAC; and Tweed Estuary SAC – three national nature reserves – Lindisfarne NNR, Farne Islands NNR and Newham Bog NNR – and 15 Sites of Special Scientific Interest ,
150-450: A relationship between the Arctic and Antarctic tree lines and the 10 °C summer isotherm; i.e., places where the average temperature in the warmest calendar month of the year is below 10 °C cannot support forests. See Köppen climate classification for more information. Otto Nordenskjöld theorized that winter conditions also play a role: His formula is W = 9 − 0.1 C , where W is
175-406: A significant manner. Thus most natural regions are homogeneous ecosystems . Human impact can be an important factor in the shaping and destiny of a particular natural region. The concept "natural region" is a large basic geographical unit, like the vast boreal forest region. The term may also be used generically, like in alpine tundra , or specifically to refer to a particular place. The term
200-476: Is a stub . You can help Misplaced Pages by expanding it . Natural region A natural region (landscape unit) is a basic geographic unit. Usually, it is a region which is distinguished by its common natural features of geography , geology , and climate . From the ecological point of view, the naturally occurring flora and fauna of the region are likely to be influenced by its geographical and geological factors, such as soil and water availability , in
225-621: Is listed as Natural Area No. 1 and also as National Character Area 1 by Natural England , the UK government's advisor on the natural environment in England. The region is a coastal strip, around 70 kilometres long and 3 to 10 kilometres wide, that runs from the Scottish Border to Amble on the River Coquet . Its narrow, low lying, windswept terrain has wide views east towards the sea and west towards
250-456: Is observed. Alpine areas are unique because of the severity and complexity of their environmental conditions. Very small changes in topography – as small as 1 foot (0.3 m) or less – may mean the difference between a windswept area or an area of snow accumulation, changing the potential productivity and plant community drastically. Between these extremes of drought versus saturation , several intermediate environments may exist all within
275-712: Is particularly useful where there is no corresponding or coterminous official region. The Fens of eastern England , the Thai highlands , and the Pays de Bray in Normandy, are examples of this. Others might include regions with particular geological characteristics, like badlands , such as the Bardenas Reales , an upland massif of acidic rock, or The Burren , in Ireland . Alpine tundra The high elevation causes an adverse climate, which
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#1732845281508300-419: Is too cold and windy to support tree growth. Alpine tundra transitions to sub-alpine forests below the tree line ; stunted forests occurring at the forest-tundra ecotone are known as krummholz . With increasing elevation it ends at the snow line where snow and ice persist through summer. Alpine tundra occurs in mountains worldwide. The flora of the alpine tundra is characterized by dwarf shrubs close to
325-833: The Alps and Pyrenees of Europe, the Himalaya and Karakoram of Asia, the Andes of South America, the Eastern Rift mountains of Africa, the Snowy Mountains of Australia, the South Island of New Zealand, and the Scandinavian Mountains . Alpine tundra occupies high-mountain summits, slopes, and ridges above timberline. Aspect plays a role as well; the treeline often occurs at higher elevations on warmer equator-facing slopes. Because
350-579: The Cheviots . The coastal scenery is diverse. The northern part has a 'hard' cliffed coast of spectacular high cliffs, offshore islands and rocky headlands, whilst the southern strip is a 'soft' alluvial coast of wide, sweeping sandy bays backed by sand dunes and intertidal flats backed by saltmarsh . Inland, the plain is intensively farmed , typically with open, mixed arable land and few trees. The valleys and coastal fringes are characterized by woodland and permanent pasture or semi-natural grassland . Roughly
375-441: The alpine zone is present only on mountains, much of the landscape is rugged and broken, with rocky, snowcapped peaks, cliffs, and talus slopes, but also contains areas of gently rolling to almost flat topography. Averaging over many locations and local microclimates , the treeline rises 75 meters (245 ft) when moving 1 degree south from 70 to 50°N, and 130 meters (430 ft) per degree from 50 to 30°N. Between 30°N and 20°S,
400-440: The average temperature in the warmest month and C the average of the coldest month, both in degrees Celsius (this would mean, for example, that if a particular location had an average temperature of −20 °C (−4 °F) in its coldest month, the warmest month would need to average 11 °C (52 °F) or higher for trees to be able to survive there). In 1947, Holdridge improved on these schemes, by defining biotemperature :
425-514: The bogs and along the brooks. Alpine meadows form where sediments from the weathering of rocks has produced soils well-developed enough to support grasses and sedges. Non-flowering lichens cling to rocks and soil. Their enclosed algal cells can photosynthesize at any temperature above 0 °C (32 °F), and the outer fungal layers can absorb more than their own weight in water. The adaptations for survival of drying winds and cold may make tundra vegetation seem very hardy, but in some respects
450-452: The dispersal of pre-existing species. Though tundra covers only a minority of the Earth's surface (17-20%), the biodiversity of plant species is important to human nutrition. Of the 20 plant species that make up 80% of human food, 7 of them (35%) originated in this region. Plants have adapted to the harsh alpine environment. Cushion plants , looking like ground-hugging clumps of moss, escape
475-488: The ground and consists mainly of perennial grasses , sedges , and forbs . Perennial herbs (including grasses, sedges, and low woody or semi-woody shrubs) dominate the alpine landscape; they have much more root and rhizome biomass than that of shoots, leaves, and flowers. The roots and rhizomes not only function in water and nutrient absorption but also play a very important role in over-winter carbohydrate storage. Annual plants are rare in this ecosystem and usually are only
500-546: The ground. The cold climate of the alpine tundra is caused by adiabatic cooling of air, and is similar to polar climate . Alpine tundra occurs at high enough altitude at any latitude . Portions of montane grasslands and shrublands ecoregions worldwide include alpine tundra. Large regions of alpine tundra occur in the North American Cordillera and parts of the northern Appalachian Mountains in North America,
525-771: The growing season in many areas. Precipitation occurs mainly as winter snow, but soil water availability is highly variable with season, location, and topography. For example, snowfields commonly accumulate on the lee sides of ridges while ridgelines may remain nearly snow free due to redistribution by wind. Some alpine habitats may be up to 70% snow free in winter. High winds are common in alpine ecosystems, and can cause significant soil erosion and be physically and physiologically detrimental to plants. Also, wind coupled with high solar radiation can promote extremely high rates of evaporation and transpiration . There have been several attempts at quantifying what constitutes an alpine climate. Climatologist Wladimir Köppen demonstrated
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#1732845281508550-578: The latter totalling 1,296 hectares. Its major watercourses are the River Tweed , which the latter section of the river forms the border with Scotland in the north, the River Coquet in the far south, Whiteadder Water and the River Aln . Holy Island is an important historic site which incorporates Lindisfarne Castle and Priory. Other historic sites include Bamburgh , Dunstanburgh and Warkworth Castles . This Northumberland location article
575-400: The mean annual temperature, where all temperatures below 0 °C are treated as 0 °C (because it makes no difference to plant life, being dormant). If the mean biotemperature is between 1.5 and 3 °C (34.7 and 37.4 °F), Holdridge quantifies the climate as alpine. Since the habitat of alpine vegetation is subject to intense radiation, wind, cold, snow, and ice, it grows close to
600-468: The strong winds blowing a few inches above them. Many flowering plants of the alpine tundra have dense hairs on stems and leaves to provide wind protection or red-colored pigments capable of converting the sun's light rays into heat. Some plants take two or more years to form flower buds, which survive the winter below the surface and then open and produce fruit with seeds in the few weeks of summer. In various areas of alpine tundra, woody plant encroachment
625-506: The treeline is roughly constant, between 3,500 and 4,000 meters (11,500 and 13,100 ft). Alpine climate is the average weather ( climate ) for the alpine tundra. The climate becomes colder when reaching higher elevations —this characteristic is described by the lapse rate of air: air tends to get colder as it rises, since it expands. The dry adiabatic lapse rate is 10 °C per km (5.5 °F per 1000 ft) of elevation or altitude. Therefore, moving up 100 meters (330 ft) on
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