South Africa
South Africa the Republic of South Africa, is the southernmost country in Africa. It is bounded to the south by 2,798 kilometres of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans. South Africa is the largest country in Southern Africa and the 25th-largest country in the world by land area and, with over 57 million people, is the world's 24th-most populous nation, it is the southernmost country on the mainland of the Eastern Hemisphere. About 80 percent of South Africans are of Sub-Saharan African ancestry, divided among a variety of ethnic groups speaking different African languages, nine of which have official status; the remaining population consists of Africa's largest communities of European and multiracial ancestry. South Africa is a multiethnic society encompassing a wide variety of cultures and religions, its pluralistic makeup is reflected in the constitution's recognition of 11 official languages, the fourth highest number in the world. Two of these languages are of European origin: Afrikaans developed from Dutch and serves as the first language of most coloured and white South Africans.
The country is one of the few in Africa never to have had a coup d'état, regular elections have been held for a century. However, the vast majority of black South Africans were not enfranchised until 1994. During the 20th century, the black majority sought to recover its rights from the dominant white minority, with this struggle playing a large role in the country's recent history and politics; the National Party imposed apartheid in 1948. After a long and sometimes violent struggle by the African National Congress and other anti-apartheid activists both inside and outside the country, the repeal of discriminatory laws began in 1990. Since 1994, all ethnic and linguistic groups have held political representation in the country's liberal democracy, which comprises a parliamentary republic and nine provinces. South Africa is referred to as the "rainbow nation" to describe the country's multicultural diversity in the wake of apartheid; the World Bank classifies South Africa as an upper-middle-income economy, a newly industrialised country.
Its economy is the second-largest in Africa, the 34th-largest in the world. In terms of purchasing power parity, South Africa has the seventh-highest per capita income in Africa; however and inequality remain widespread, with about a quarter of the population unemployed and living on less than US$1.25 a day. South Africa has been identified as a middle power in international affairs, maintains significant regional influence; the name "South Africa" is derived from the country's geographic location at the southern tip of Africa. Upon formation, the country was named the Union of South Africa in English, reflecting its origin from the unification of four separate British colonies. Since 1961, the long form name in English has been the "Republic of South Africa". In Dutch, the country was named Republiek van Zuid-Afrika, replaced in 1983 by the Afrikaans Republiek van Suid-Afrika. Since 1994, the Republic has had an official name in each of its 11 official languages. Mzansi, derived from the Xhosa noun umzantsi meaning "south", is a colloquial name for South Africa, while some Pan-Africanist political parties prefer the term "Azania".
South Africa contains human-fossil sites in the world. Archaeologists have recovered extensive fossil remains from a series of caves in Gauteng Province; the area, a UNESCO World Heritage site, has been branded "the Cradle of Humankind". The sites include one of the richest sites for hominin fossils in the world. Other sites include Gondolin Cave Kromdraai, Coopers Cave and Malapa. Raymond Dart identified the first hominin fossil discovered in Africa, the Taung Child in 1924. Further hominin remains have come from the sites of Makapansgat in Limpopo Province and Florisbad in the Free State Province, Border Cave in KwaZulu-Natal Province, Klasies River Mouth in Eastern Cape Province and Pinnacle Point and Die Kelders Cave in Western Cape Province; these finds suggest that various hominid species existed in South Africa from about three million years ago, starting with Australopithecus africanus. There followed species including Australopithecus sediba, Homo ergaster, Homo erectus, Homo rhodesiensis, Homo helmei, Homo naledi and modern humans.
Modern humans have inhabited Southern Africa for at least 170,000 years. Various researchers have located pebble tools within the Vaal River valley. Settlements of Bantu-speaking peoples, who were iron-using agriculturists and herdsmen, were present south of the Limpopo River by the 4th or 5th century CE, they displaced and absorbed the original Khoisan speakers, the Khoikhoi and San peoples. The Bantu moved south; the earliest ironworks in modern-day KwaZulu-Natal Province are believed to date from around 1050. The southernmost group was the Xhosa people, whose language incorporates certain linguistic traits from the earlier Khoisan people; the Xhosa reached the Great Fish River, in today's Eastern Cape Province. As they migrated, these larger Iron Age populations
Klamath Mountains (ecoregion)
The Klamath Mountains ecoregion of Oregon and California lies inland and north of the Coast Range ecoregion, extending from the Umpqua River in the north to the Sacramento Valley in the south. It encompasses the dissected ridges and valleys of the Klamath and Siskiyou Mountains, it corresponds to the Level III ecoregion designated by the Environmental Protection Agency and to the Klamath-Siskiyou forests ecoregion designated by the World Wide Fund for Nature. The ecoregion known as a geomorphic province, was unglaciated during the Pleistocene epoch, when it served as a refuge for northern plant species, its mix of granitic, sedimentary and extrusive rocks contrasts with the predominantly volcanic rocks of the Cascades ecoregion to the northeast. The mild, subhumid climate of the region is characterized by a lengthy summer drought, it supports a mosaic of both northern Californian and Pacific Northwestern conifers and hardwoods. The ecoregion harbors rich biodiversity, with several distinct plant communities, including temperate rain forests, moist inland forests, oak forests and savannas, high elevation forests, alpine grasslands.
Thirty conifer species inhabit the region, including seven endemic species, making the region one of the richest coniferous forest regions of the world in species diversity. The region has several edaphic plant communities, notably those of the region's serpentine outcrops. Conifer species include Coast Douglas-fir, Lawson's Cypress, Ponderosa Pine, Sugar Pine, Mountain Hemlock, White Fir, Red Fir, Weeping Spruce, Coast Redwood, Pacific Yew; these forests mark the northern extent of the range for California Buckeye. The Oregon portion of the ecoregion has been subdivided into seven Level IV ecoregions, as described below; the Rogue/Illinois Valleys ecoregion includes terraces and floodplains in the Rogue and Illinois river valleys at an elevation of 900 to 2,000 feet. The valleys supported Oregon white oak and California black oak woodland, with Pacific madrone, ponderosa pine, grassland. Common understory plants included California fescue and serviceberry. Riparian areas supported cottonwood.
Much of the land has been developed for agricultural or residential use, little of the original vegetation remains. Remnants of oak savanna, prairie vegetation, seasonal ponds persist on the mesa tops of the Table Rocks north of Medford. Elsewhere, land uses include orchards and pastureland. Climate and resulting land use are more similar to Northern California’s inland valleys than to the Willamette Valley ecoregion to the north; the region covers 285 square miles in Oregon, in three separate areas around Medford and Ashland, Grants Pass, Cave Junction. The Oak Savanna Foothills ecoregion consists of moderately sloping mountain foothills bordering the Rogue and Illinois river valleys and sharing their Mediterranean climate. Elevation varies from 1,400 to 4,000 feet; the driest area, east of Medford, is dominated by Oregon white oak and California black oak woodlands, grassland-savanna, ponderosa pine, Coast Douglas-fir. The wetter foothills flanking the Illinois Valley support Douglas-fir and California incense-cedar.
Understory species include oceanspray, Western poison-oak, Idaho fescue, California brome, roughstalk bluegrass, ceanothus. The region is lower and less dissected, with more oak woodland and less closed-canopied forest than the Inland Siskiyous, it covers 818 square miles in Oregon. The Umpqua Interior Foothills ecoregion is a complex of foothills and narrow valleys containing fluvial terraces and floodplains. Elevation varies from 400 to 2,800 feet, it is drier than the foothills of the Willamette Valley because the summer Pacific high pressure system arrives earlier and remains longer than in ecoregions to the north. Summers are hot and dry, soils have a xeric moisture regime in contrast to the udic soils of the Mid-Coastal Sedimentary ecoregion to the west; the slopes are covered by Oregon white oak woodland, Douglas-fir, grand fir, ponderosa pine, madrone and chinkapin, with an understory chaparral community that includes snowberry, Oregon grape, poison oak and swordfern. Many areas have been converted to pastureland, vineyards and row crops.
It covers 921 square miles including the city of Roseburg. The Serpentine Siskiyous ecoregion consists of dissected mountains containing perennial, high gradient streams at an elevation of 1,500 to 4,300 feet, it is lithogically distinct from the rest of the Klamath Mountains ecoregion. Many plants have difficulty growing in its serpentine soils due to a shortage of calcium and high levels of magnesium and chromium; as a result, vegetation is sparse and composed of specialist species that have evolved to grow in the toxic and nutrient-poor serpentine soils. It supports a mixed conifer forest of Jeffrey pine, incense-cedar, Douglas-fir, montane chaparral composed of manzanita, Idaho fescue, Lemmon needlegrass. Historic gold, chromite and mercury mining have contributed to water quality problems; the region covers 440 square miles in Oregon, including portions of the Rogue River – Siskiyou National Forest and the Kalmiopsis and Wild Rogue wildernesses. Contiguous areas in California
Biodiversity
Biodiversity refers to the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic and ecosystem level. Terrestrial biodiversity is greater near the equator, the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, is richest in the tropics; these tropical forest ecosystems cover less than 10 percent of earth's surface, contain about 90 percent of the world's species. Marine biodiversity is highest along coasts in the Western Pacific, where sea surface temperature is highest, in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity tends to cluster in hotspots, has been increasing through time, but will be to slow in the future. Rapid environmental changes cause mass extinctions. More than 99.9 percent of all species that lived on Earth, amounting to over five billion species, are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.
More in May 2016, scientists reported that 1 trillion species are estimated to be on Earth with only one-thousandth of one percent described. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all organisms living on Earth; the age of the Earth is about 4.54 billion years. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.
According to one of the researchers, "If life arose quickly on Earth.. it could be common in the universe."Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic eon marked a rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of multicellular phyla first appeared; the next 400 million years included repeated, massive biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse led to a great loss of animal life; the Permian–Triassic extinction event, 251 million years ago, was the worst. The most recent, the Cretaceous–Paleogene extinction event, occurred 65 million years ago and has attracted more attention than others because it resulted in the extinction of the dinosaurs; the period since the emergence of humans has displayed an ongoing biodiversity reduction and an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is caused by human impacts habitat destruction.
Conversely, biodiversity positively impacts human health in a number of ways, although a few negative effects are studied. The United Nations designated 2011–2020 as the United Nations Decade on Biodiversity. 1916 - The term biological diversity was used first by J. Arthur Harris in "The Variable Desert," Scientific American, JSTOR 6182: "The bare statement that the region contains a flora rich in genera and species and of diverse geographic origin or affinity is inadequate as a description of its real biological diversity." 1975 - The term natural diversity was introduced 1980 - Thomas Lovejoy introduced the term biological diversity to the scientific community in a book.. It became used. 1985 -The contracted form biodiversity was coined by W. G. Rosen 1985 - The term "biodiversity" appears in the article, "A New Plan to Conserve the Earth's Biota" by Laura Tangley. 1988 - The term biodiversity first appeared in a publication. The present - the term has achieved widespread use. "Biodiversity" is most used to replace the more defined and long established terms, species diversity and species richness.
Biologists most define biodiversity as the "totality of genes and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances and presents a unified view of the traditional types of biological variety identified: taxonomic diversity ecological diversity morphological diversity functional diversity This multilevel construct is consistent with Datman and Lovejoy. An explicit definition consistent with this interpretation was first given in a paper by Bruce A. Wilcox commissioned by the International Union for the Conservation of Nature and Natural Resources for the 1982 World National Parks Conference. Wilcox's definition was "Biological diversity is the variety of life forms...at all levels of biologi
Ecology
Ecology is the branch of biology which studies the interactions among organisms and their environment. Objects of study include interactions of organisms that include biotic and abiotic components of their environment. Topics of interest include the biodiversity, distribution and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, the non-living components of their environment. Ecosystem processes, such as primary production, nutrient cycling, niche construction, regulate the flux of energy and matter through an environment; these processes are sustained by organisms with specific life history traits. Biodiversity means the varieties of species and ecosystems, enhances certain ecosystem services. Ecology is not synonymous with natural history, or environmental science, it overlaps with the related sciences of evolutionary biology and ethology. An important focus for ecologists is to improve the understanding of how biodiversity affects ecological function.
Ecologists seek to explain: Life processes and adaptations The movement of materials and energy through living communities The successional development of ecosystems The abundance and distribution of organisms and biodiversity in the context of the environment. Ecology has practical applications in conservation biology, wetland management, natural resource management, city planning, community health, economics and applied science, human social interaction. For example, the Circles of Sustainability approach treats ecology as more than the environment'out there', it is not treated as separate from humans. Organisms and resources compose ecosystems which, in turn, maintain biophysical feedback mechanisms that moderate processes acting on living and non-living components of the planet. Ecosystems sustain life-supporting functions and produce natural capital like biomass production, the regulation of climate, global biogeochemical cycles, water filtration, soil formation, erosion control, flood protection, many other natural features of scientific, economic, or intrinsic value.
The word "ecology" was coined in 1866 by the German scientist Ernst Haeckel. Ecological thought is derivative of established currents in philosophy from ethics and politics. Ancient Greek philosophers such as Hippocrates and Aristotle laid the foundations of ecology in their studies on natural history. Modern ecology became a much more rigorous science in the late 19th century. Evolutionary concepts relating to adaptation and natural selection became the cornerstones of modern ecological theory; the scope of ecology contains a wide array of interacting levels of organization spanning micro-level to a planetary scale phenomena. Ecosystems, for example, contain interacting life forms. Ecosystems are dynamic, they do not always follow a linear successional path, but they are always changing and sometimes so that it can take thousands of years for ecological processes to bring about certain successional stages of a forest. An ecosystem's area can vary from tiny to vast. A single tree is of little consequence to the classification of a forest ecosystem, but critically relevant to organisms living in and on it.
Several generations of an aphid population can exist over the lifespan of a single leaf. Each of those aphids, in turn, support diverse bacterial communities; the nature of connections in ecological communities cannot be explained by knowing the details of each species in isolation, because the emergent pattern is neither revealed nor predicted until the ecosystem is studied as an integrated whole. Some ecological principles, however, do exhibit collective properties where the sum of the components explain the properties of the whole, such as birth rates of a population being equal to the sum of individual births over a designated time frame; the main subdisciplines of ecology, population ecology and ecosystem ecology, exhibit a difference not only of scale, but of two contrasting paradigms in the field. The former focus on organisms distribution and abundance, while the focus on materials and energy fluxes; the scale of ecological dynamics can operate like a closed system, such as aphids migrating on a single tree, while at the same time remain open with regard to broader scale influences, such as atmosphere or climate.
Hence, ecologists classify ecosystems hierarchically by analyzing data collected from finer scale units, such as vegetation associations and soil types, integrate this information to identify emergent patterns of uniform organization and processes that operate on local to regional and chronological scales. To structure the study of ecology into a conceptually manageable framework, the biological world is organized into a nested hierarchy, ranging in scale from genes, to cells, to tissues, to organs, to organisms, to species, to populations, to communities, to ecosystems, to biomes, up to the level of the biosphere; this framework exhibits non-linear behaviors.
Pacific Northwest
The Pacific Northwest, sometimes referred to as Cascadia, is a geographic region in western North America bounded by the Pacific Ocean to the west and by the Cascade Mountain Range on the east. Though no official boundary exists, the most common conception includes the Canadian province of British Columbia and the U. S. states of Idaho and Washington. Broader conceptions reach north into Southeast Alaska and Yukon, south into northern California, east to the Continental Divide to include Western Montana and parts of Wyoming. Narrower conceptions may be limited to the coastal areas west of the Coast mountains; the variety of definitions can be attributed to overlapping commonalities of the region's history, geography and other factors. The Northwest Coast is the coastal region of the Pacific Northwest, the Northwest Plateau is the inland region; the term "Pacific Northwest" should not be confused with the Northwest Territory or the Northwest Territories of Canada. The region's largest metropolitan areas are Greater Seattle, with 3.8 million people.
A key aspect of the Pacific Northwest is the US–Canada international border, which the United States and the United Kingdom established at a time when the region's inhabitants were composed of indigenous peoples. The border—in two sections, along the 49th parallel south of British Columbia and the Alaska Panhandle west of northern British Columbia—has had a powerful effect on the region. According to Canadian historian Ken Coates, the border has not influenced the Pacific Northwest—rather, "the region's history and character have been determined by the boundary". Definitions of the Pacific Northwest region vary, Pacific Northwesterners do not agree on the exact boundary; the most common conception includes the U. S. states of Idaho and Washington and the Canadian province of British Columbia. Broader definitions of the region have included the U. S. states of Alaska and parts of the states of California and Wyoming, the Canadian territory of the Yukon. Definitions based on the historic Oregon Country reach east to the Continental Divide, thus including all of Idaho and parts of western Montana and western Wyoming.
Sometimes, the Pacific Northwest is defined as being the Northwestern United States excluding Canada. Note that these types of definitions are made by government agencies whose scope is limited to the United States; the Pacific Northwest has been occupied by a diverse array of indigenous peoples for millennia. The Pacific Coast is seen by some scholars as a major coastal migration route in the settlement of the Americas by late Pleistocene peoples moving from northeast Asia into the Americas; the coastal migration hypothesis has been bolstered by findings such as the report that the sediments in the Port Eliza Cave on Vancouver Island indicate the possibility of survivable climate as far back as 16 kya in the area, while the continental ice sheets were nearing their maximum extent. Other evidence for human occupation dating back as much as 14.5 kya is emerging from Paisley Caves in south-central Oregon. However, despite such research, the coastal migration hypothesis is still subject to considerable debate.
Due in part to the richness of Pacific Northwest Coast and river fisheries, some of the indigenous peoples developed complex sedentary societies, while remaining hunter-gatherers. The Pacific Northwest Coast is one of the few places where politically complex hunter-gatherers evolved and survived to historic contacts, therefore has been vital for anthropologists and archaeologists seeking to understand how complex hunter and gatherer societies function; when Europeans first arrived on the Northwest Coast, they found one of the world's most complex hunting and fishing societies, with large sedentary villages, large houses, systems of social rank and prestige, extensive trade networks, many other factors more associated with societies based on domesticated agriculture. In the interior of the Pacific Northwest, the indigenous peoples, at the time of European contact, had a diversity of cultures and societies; some areas were home to egalitarian societies. Others along major rivers such as the Columbia and Fraser, had complex, sedentary societies rivaling those of the coast.
In British Columbia and Southeast Alaska, the Tlingit and Haida erected large and elaborately carved totem poles that have become iconic of Pacific Northwest artistic traditions. Throughout the Pacific Northwest, thousands of indigenous people live, some continue to practice their rich cultural traditions, "organizing their societies around cedar and salmon". In 1579 the British captain and erstwhile privateer Francis Drake sailed up the west coast of North America as far as Oregon before returning south to land and make ship repairs. At this landing site near present-day San Francisco, Drake made a symbolic claim of the region for England, naming it New Albion. Juan de Fuca, a Greek captain sailing for the Crown of Spain found the Strait of Juan de Fuca around 1592; the strait was whether he discovered it or not has long been questioned. During the early 1740s, Imperial Russia sent the Dane Vitus Bering to the region. By the late 18th century and into the mid-19th century, Russian settlers had established several posts and communities on the northeast Pacific coast reaching a
Elevation
The elevation of a geographic location is its height above or below a fixed reference point, most a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface. The term elevation is used when referring to points on the Earth's surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, depth is used for points below the surface. Elevation is not to be confused with the distance from the center of the Earth. Due to the equatorial bulge, the summits of Mount Everest and Chimborazo have the largest elevation and the largest geocentric distance. GIS or geographic information system is a computer system that allows for visualizing, manipulating and storage of data with associated attributes. GIS offers better understanding of relationships of the landscape at different scales. Tools inside the GIS allow for manipulation of data for spatial cartography. A topographical map is the main type of map used to depict elevation through use of contour lines.
In a Geographic Information System, digital elevation models are used to represent the surface of a place, through a raster dataset of elevations. Digital terrain models are another way to represent terrain in GIS. USGS is developing a 3D Elevation Program to keep up with growing needs for high quality topographic data. 3DEP is a collection of enhanced elevation data in the form of high quality LiDAR data over the conterminous United States and the U. S. territories. There are three bare earth DEM layers in 3DEP which are nationally seamless at the resolution of 1/3, 1, 2 arcseconds; this map is derived from GTOPO30 data that describes the elevation of Earth's terrain at intervals of 30 arcseconds. It uses shading instead of contour lines to indicate elevation. Height Orthometric height Hypsography Geodesy Geodesy of North America Sea Level Datum of 1929 National Geodetic Vertical Datum of 1929 North American Vertical Datum of 1988 List of European cities by elevation List of highest mountains List of highest towns by country Normaal Amsterdams Peil Normalhöhennull Physical geography Table of the highest major summits of North America Temperature lapse rate Topographic isolation Topographic prominence Topography Vertical pressure variation U.
S. National Geodetic Survey website Geodetic Glossary @ NGS NGVD 29 to NAVD 88 online elevation converter @ NGS United States Geological Survey website Geographical Survey Institute Downloadable ETOPO2 Raw Data Database Downloadable ETOPO5 Raw Data Database Find the elevation of any place
Bog
A bog or bogland is a wetland that accumulates peat, a deposit of dead plant material—often mosses, in a majority of cases, sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire and muskeg, they are covered in ericaceous shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink. Bogs occur where the water at the ground surface is low in nutrients. In some cases, the water is derived from precipitation, in which case they are termed ombrotrophic. Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general, the low fertility and cool climate result in slow plant growth, but decay is slower owing to the saturated soil. Hence, peat accumulates. Large areas of the landscape can be covered many meters deep in peat. Bogs have distinctive assemblages of animal and plant species, are of high importance for biodiversity in landscapes that are otherwise settled and farmed.
Bogs are distributed in cold, temperate climes in boreal ecosystems in the Northern Hemisphere. The world's largest wetland is the peat bogs of the Western Siberian Lowlands in Russia, which cover more than a million square kilometres. Large peat bogs occur in North America the Hudson Bay Lowland and the Mackenzie River Basin, they are less common in the Southern Hemisphere, with the largest being the Magellanic moorland, comprising some 44,000 square kilometres. Sphagnum bogs were widespread in northern Europe but have been cleared and drained for agriculture. A 2014 expedition leaving from Itanga village, Republic of the Congo, discovered a peat bog "as big as England" which stretches into neighboring Democratic Republic of Congo. There are many specialised animals and plants associated with bog habitat. Most are capable of waterlogging. Sphagnum is abundant, along with ericaceous shrubs; the shrubs are evergreen, understood to assist in conservation of nutrients. In drier locations, evergreen trees can occur, in which case the bog blends into the surrounding expanses of boreal evergreen forest.
Sedges are one of the more common herbaceous species. Carnivorous plants such as sundews and pitcher plants have adapted to the low-nutrient conditions by using invertebrates as a nutrient source. Orchids have adapted to these conditions through the use of mycorrhizal fungi to extract nutrients; some shrubs such as Myrica gale have root nodules in which nitrogen fixation occurs, thereby providing another supplemental source of nitrogen. Bogs are recognized as a significant/specific habitat type by a number of governmental and conservation agencies, they can provide habitat for mammals, such as caribou and beavers, as well as for species of nesting shorebirds, such as Siberian cranes and yellowlegs. The United Kingdom in its Biodiversity Action Plan establishes bog habitats as a priority for conservation. Russia has a large reserve system in the West Siberian Lowland; the highest protected status occurs in Zapovedniks. Bogs have distinctive insects. In Ireland, the viviparous lizard, the only known reptile in the country, dwells in bogland.
Bog habitats may develop depending on the climate and topography. One way of classifying bogs is based upon their location in the landscape, their source of water; these develop in sloping valleys or hollows. A layer of peat fills the deepest part of the valley, a stream may run through the surface of the bog. Valley bogs may develop in dry and warm climates, but because they rely on ground or surface water, they only occur on acidic substrates; these develop over either non-acidic or acidic substrates. Over centuries there is a progression from open lake, to a marsh, to a fen, to a carr, as silt or peat accumulates within the lake. Peat builds up to a level where the land surface is too flat for ground or surface water to reach the center of the wetland; this part, becomes wholly rain-fed, the resulting acidic conditions allow the development of bog. The bog continues to form peat, over time a shallow dome of bog peat develops into a raised bog; the dome is a few meters high in the center and is surrounded by strips of fen or other wetland vegetation at the edges or along streamsides where groundwater can percolate into the wetland.
The various types of raised bog may be divided into: Coastal bog Plateau bog Upland bog Kermi bog String bog Palsa bog Polygonal bog In cool climates with high rainfall, the ground surface may remain waterlogged for much of the time, providing conditions for the development of bog vegetation. In these circumstances, bog develops as a layer "blanketing" much of the land, including hilltops and slopes. Although a blanket bog is more common on acidic substrates, under some conditions it may develop on neutral or alkaline ones, if abundant acidic rainwater predominates over the groundwater. A blanket bog cannot occur in drier or warmer climates, because under those conditions hilltops and sloping ground dry out
