Moorland

Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland nowadays generally means uncultivated hill land (such as Dartmoor in South West England), but includes low-lying wetlands (such as Sedgemoor, also South West England). It is closely related to heath although experts disagree on precisely what distinguishes the types of vegetation. Generally, moor refers to highland, high rainfall zones, whereas heath refers to lowland zones which are more likely to be the result of human activity. Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland nowadays generally means uncultivated hill land (such as Dartmoor in South West England), but includes low-lying wetlands (such as Sedgemoor, also South West England). It is closely related to heath although experts disagree on precisely what distinguishes the types of vegetation. Generally, moor refers to highland, high rainfall zones, whereas heath refers to lowland zones which are more likely to be the result of human activity. Moorland habitats mostly occur in tropical Africa, northern and western Europe and neotropical South America. Most of the world's moorlands are very diverse ecosystems. In the extensive moorlands of the tropics biodiversity can be extremely high. Moorland also bears a relationship to tundra (where the subsoil is permafrost or permanently frozen soil), appearing as the tundra retreats and inhabiting the area between the permafrost and the natural tree zone. The boundary between tundra and moorland constantly shifts with climate change. Heathland and moorland are the most extensive areas of semi-natural vegetation in the British Isles. The eastern British moorlands are similar to heaths but are differentiated by having a covering of peat. On western moors the peat layer may be several metres thick. Scottish 'muirs' are generally heather moors, but also have extensive covering of grass, cotton-grass, mosses, bracken and under-shrubs such as crowberry, with the wetter moorland having sphagnum moss merging into bog-land. There is uncertainty about how many moors were created by human activity. Oliver Rackham writes that pollen analysis shows that some moorland, such as in the islands and extreme north of Scotland, are clearly natural, never having had trees, whereas much of the Pennine moorland area was forested in Mesolithic times. How much the deforestation was caused by climatic changes and how much by human activity is uncertain. A variety of distinct habitat types are found in different world regions of moorland. The wildlife and vegetation forms often lead to high endemism because of the severe soil and microclimate characteristics. For example, in England's Exmoor is found the rarehorse breed the Exmoor Pony, which has adapted to the harsh conditions of that environment. In Europe, the associated fauna consists of bird species such as red grouse, hen harrier, merlin, golden plover, curlew, skylark, meadow pipit, whinchat, ring ouzel, and twite. Other species dominate in moorlands elsewhere. Reptiles are few due to the cooler conditions. In Europe, only the common viper is frequent, though in other regions moorlands are commonly home to dozens of reptile species. Amphibians such as frogs are well represented in moorlands. When moorland is overgrazed, woody vegetation is often lost, being replaced by coarse, unpalatable grasses and bracken, with a greatly reduced fauna. Some hill sheep breeds, such as Scottish Blackface and the Lonk, thrive on the austere conditions of heather moors. Burning of moorland has been practised for a number of reasons, for example when grazing is insufficient to control growth. This is recorded in Britain in the fourteenth century. Uncontrolled burning frequently caused (and causes) problems, and was forbidden by statute in 1607. With the rise of sheep and grouse management in the nineteenth century it again became common practice. Heather is burnt at about 10 or 12 years old when it will regenerate easily. Left longer, the woodier stems will burn more aggressively and will hinder regrowth. Burning of moorland vegetation needs to be very carefully controlled as the peat itself can catch fire, and this can be difficult if not impossible to extinguish. In addition, uncontrolled burning of heather can promote alternative bracken and rough grass growth which ultimately produces poorer grazing. As a result, burning is now a controversial practice; Rackham calls it 'second-best land management'. Mechanical cutting of the heather has been used in Europe, but it is important for the material to be removed to avoid smothering regrowth. If heather and other vegetation are left for too long, a large volume of dry and combustible material builds up. This may result in a wildfire burning out a large area, although it has been found that heather seeds germinate better if subject to the brief heat of controlled burning.