141-645: The Little Sandy Desert ( LSD ) is a desert region in the state of Western Australia , lying to the east of the Pilbara and north of the Gascoyne regions. It is part of the Western Desert cultural region, and was declared an interim Australian bioregion in the 1990s. Indigenous groups that have identified with the region include the Mandilara , an Aboriginal Australian group who are regarded as
282-530: A mammal adapted to desert life. It minimizes its water loss by producing concentrated urine and dry dung , and is able to lose 40% of its body weight through water loss without dying of dehydration. Carnivores can obtain much of their water needs from the body fluids of their prey. Many other hot desert animals are nocturnal , seeking out shade during the day or dwelling underground in burrows. At depths of more than 50 cm (20 in), these remain at between 30 and 32 °C (86 and 90 °F) regardless of
423-456: A sand blasting mechanism which grinds away solid objects in its path as the kinetic energy of the wind is transferred to the ground. The sand eventually ends up deposited in level areas known as sand-fields or sand-seas, or piled up in dunes. Many people think of deserts as consisting of extensive areas of billowing sand dunes because that is the way they are often depicted on TV and in films, but deserts do not always look like this. Across
564-428: A semi-arid climate and are less extreme than regular deserts. Like arid deserts, temperatures can vary greatly in semi deserts. They share some characteristics of a true desert and are usually located at the edge of deserts and continental dry areas. They usually receive precipitation from 250 to 500 mm (9.8 to 19.7 in) but this can vary due to evapotranspiration and soil nutrition. Semi-deserts can be found in
705-432: A 2.3 m (7.5 ft) wingspan. The average weight for males is 6.3 kg (14 lb), with a range of 4.3 to 12.76 kg (9.5 to 28.1 lb). The female is quite a bit smaller at 80 cm (31 in) tall, with a 1.8 m (5.9 ft) wingspan and an average body mass of 3.2 kg (7.1 lb) in a range of 2.4 to 6.35 kg (5.3 to 14.0 lb) but is similarly coloured. The largest male recorded
846-438: A desert conglomerate . In time, bacteria that live on the surface of the stones accumulate a film of minerals and clay particles, forming a shiny brown coating known as desert varnish . Other non-sandy deserts consist of exposed outcrops of bedrock , dry soils or aridisols , and a variety of landforms affected by flowing water , such as alluvial fans , sinks or playas , temporary or permanent lakes , and oases. A hamada
987-505: A destructive effect on the exposed rocky surfaces. The repeated fluctuations put a strain on exposed rock and the flanks of mountains crack and shatter. Fragmented strata slide down into the valleys where they continue to break into pieces due to the relentless sun by day and chill by night. Successive strata are exposed to further weathering. The relief of the internal pressure that has built up in rocks that have been underground for aeons can cause them to shatter. Exfoliation also occurs when
1128-469: A height around 25 metres was recorded in Arnhemland, after a period of posturing and chasing by the males in dispute, but this may be unusual behaviour due to the greater risk of injury in this larger species of bustard. Ardeotis australis does not make any attempt to construct a nest. The clutch size is usually one egg, sometimes two, laid close to a small shrub or bush on unadorned ground. The shell
1269-415: A low basal metabolic rate and by remaining underground during the heat of the day, reducing loss of water through its skin and respiratory system when at rest. Herbivorous mammals obtain moisture from the plants they eat. Species such as the addax antelope , dik-dik , Grant's gazelle and oryx are so efficient at doing this that they apparently never need to drink. The camel is a superb example of
1410-484: A number of ways, generally combining total precipitation, number of days on which this falls, temperature, and humidity, and sometimes additional factors. For example, Phoenix, Arizona , receives less than 250 mm (9.8 in) of precipitation per year, and is immediately recognized as being located in a desert because of its aridity-adapted plants. The North Slope of Alaska's Brooks Range also receives less than 250 mm (9.8 in) of precipitation per year and
1551-423: A series of long, linear dunes known as seif dunes may form. These also occur parallel to a strong wind that blows in one general direction. Transverse dunes run at a right angle to the prevailing wind direction. Star dunes are formed by variable winds, and have several ridges and slip faces radiating from a central point. They tend to grow vertically; they can reach a height of 500 m (1,600 ft), making them
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#17327583238321692-461: A sparse trophic network . Plant growth is limited by rainfall , temperature extremes and desiccating winds. Deserts have strong temporal variability in the availability of resources due to the total amount of annual rainfall and the size of individual rainfall events. Resources are often ephemeral or episodic, and this triggers sporadic animal movements and 'pulse and reserve' or 'boom-bust' ecosystem dynamics. Erosion and sedimentation are high due to
1833-439: A steady wind begins to blow, fine particles lying on the exposed ground begin to vibrate. At greater wind speeds, some particles are lifted into the air stream. When they land, they strike other particles which may be jerked into the air in their turn, starting a chain reaction . Once ejected, these particles move in one of three possible ways, depending on their size, shape and density; suspension , saltation or creep. Suspension
1974-584: A storm that may be many kilometers away. Most deserts are in basins with no drainage to the sea but some are crossed by exotic rivers sourced in mountain ranges or other high rainfall areas beyond their borders. The River Nile , the Colorado River and the Yellow River do this, losing much of their water through evaporation as they pass through the desert and raising groundwater levels nearby. There may also be underground sources of water in deserts in
2115-466: A study published in September 2018 showed that humans had in fact occupied the site around 47,830 Cal BP . This and other recent studies, which were done at the request of the native title holders, shed new light on the concept of deep time , as well as the social geography of arid zones . The study, using archaeobotany to establish its findings, found that wattle had been collected throughout
2256-485: A tolerable level. In many ways, birds are the ablest to do this of the higher animals. They can move to areas of greater food availability as the desert blooms after local rainfall and can fly to faraway waterholes. In hot deserts, gliding birds can remove themselves from the over-heated desert floor by using thermals to soar in the cooler air at great heights. In order to conserve energy, other desert birds run rather than fly. The cream-colored courser flits gracefully across
2397-632: A type of cold desert . While they do not lack water, having a persistent cover of snow and ice, this is merely due to marginal evaporation rates and low precipitation. The McMurdo dry valleys of Antarctica, which lack water (whether rain, ice, or snow) much like a non-polar desert and even have such desert features as hypersaline lakes and intermittent streams that resemble (except for being frozen at their surfaces) hot or cold deserts for extreme aridity and lack of precipitation of any kind. Extreme winds and not seasonal heat desiccate these nearly-lifeless terrains. The concept of "biological desert" redefines
2538-503: A wide area of the Australian continent and occasionally extends to southern parts of Papua New Guinea and Indonesia. The occurrence in the southeast of Australia has contracted and it no longer occurs in areas where it once recorded. Individual range has been studied by tracking of the birds, via satellite and tagging or community derived surveys, indicating that local populations in wetter regions are more permanent and localised than
2679-400: A year; they have no annual seasonal cycle of precipitation and experience twelve-month periods with no rainfall at all. Arid deserts receive between 25 and 200 mm (1 and 8 in) in a year and semiarid deserts between 200 and 500 mm (8 and 20 in). However, such factors as the temperature, humidity, rate of evaporation and evapotranspiration, and the moisture storage capacity of
2820-472: Is 150 km (93 mi) long and is the largest oasis in the Libyan Desert. A lake occupied this depression in ancient times and thick deposits of sandy-clay resulted. Wells are dug to extract water from the porous sandstone that lies underneath. Seepages may occur in the walls of canyons and pools may survive in deep shade near the dried up watercourse below. Lakes may form in basins where there
2961-512: Is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation . About one-third of the land surface of the Earth is arid or semi-arid . This includes much of the polar regions , where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by
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#17327583238323102-538: Is a jumble of eroded sandstone outcrops , canyons , blocks, pinnacles , fissures , slabs and ravines . In some places the wind has carved holes or arches, and in others, it has created mushroom-like pillars narrower at the base than the top. On the Colorado Plateau , it is water that has been the prevailing eroding force. Here, rivers, such as the Colorado , have cut their way over the millennia through
3243-458: Is a large terrestrial bird that resembles an American turkey in its form and behaviour. It is readily distinguished by its large size, long legs and habits while slowly striding across open plains. The general coloration of A. australis is black at the crown and nape, the long neck is pale grey at the front, and brown plumage cover the wings and upper body. The sexes are similar in appearance, females are smaller in stature, wingspan and weight than
3384-542: Is a type of desert landscape consisting of a high rocky plateau where the sand has been removed by aeolian processes . Other landforms include plains largely covered by gravels and angular boulders, from which the finer particles have been stripped by the wind. These are called "reg" in the western Sahara, "serir" in the eastern Sahara, "gibber plains" in Australia and "saï" in central Asia. The Tassili Plateau in Algeria
3525-622: Is also commonly referred to as the plains turkey , and in Central Australia as the bush turkey , particularly by Aboriginal people, who hunt it, although the latter name may also be used for the Australian brushturkey , as well as the orange-footed scrubfowl . The species was first described by John Edward Gray in 1829, who assigned it the name Otis australis . Gray's specimen was obtained in New South Wales and
3666-455: Is around twice that length. The species is nomadic, flying to areas when food becomes plentiful, and capable of travelling long distances. They were once widespread and common to the open plains of Australia, but became rare in regions that have been used for farming. The bustard is omnivorous, mostly consuming the fruit or seed of plants, but also eating invertebrates such as crickets, grasshoppers, smaller mammals, birds and reptiles. The species
3807-633: Is continuous above 5,600 m (18,400 ft). Nevertheless, there is some plant life in the Atacama, in the form of specialist plants that obtain moisture from dew and the fogs that blow in from the Pacific. When rain falls in deserts, as it occasionally does, it is often with great violence. The desert surface is evidence of this with dry stream channels known as arroyos or wadis meandering across its surface. These can experience flash floods , becoming raging torrents with surprising rapidity after
3948-479: Is higher than that of forests or the sea. A desert is a region of land that is very dry because it receives low amounts of precipitation (usually in the form of rain, but it may be snow, mist or fog), often has little coverage by plants, and in which streams dry up unless they are supplied by water from outside the area. Deserts generally receive less than 250 mm (10 in) of precipitation each year. The potential evapotranspiration may be large but (in
4089-404: Is marked with olive-brown blotching and streaks over most of the surface, perhaps more completely covering the larger end of the egg, the background colour is a lighter shade of olive-brown or olive-green. Incubation of the brood is maintained by the female. The dimensions of the egg are 75 × 55 millimetres. The chick will leave the site after emerging from its shell to avoid predation, and relies on
4230-668: Is observed on artificial cleared areas such as golf courses and farmland. The historical range in Southwest Australia included the dunes and alluvial flats of the Swan Coastal Plain , as far south as Busselton , and at the interior in what became the Wheatbelt . Vagrants were seen in other areas associated with the higher rainfall forest of the southwest region, although the species avoided forest and densely vegetated areas. Anecdotal reports from residents of
4371-560: Is often classified as a cold desert. Other regions of the world have cold deserts, including areas of the Himalayas and other high-altitude areas in other parts of the world. Polar deserts cover much of the ice-free areas of the Arctic and Antarctic. A non-technical definition is that deserts are those parts of Earth's surface that have insufficient vegetation cover to support a human population. Potential evapotranspiration supplements
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4512-434: Is often less than 40 mm or 1.5 in) to being very far from the nearest available sources of moisture and are often in the lee of mountain ranges. Montane deserts are normally cold, or may be scorchingly hot by day and very cold by night as is true of the northeastern slopes of Mount Kilimanjaro . Polar deserts such as McMurdo Dry Valleys remain ice-free because of the dry katabatic winds that flow downhill from
4653-421: Is only possible for particles less than 0.1 mm (0.0039 in) in diameter. In a dust storm, these fine particles are lifted up and wafted aloft to heights of up to 6 km (3.7 mi). They reduce visibility and can remain in the atmosphere for days on end, conveyed by the trade winds for distances of up to 6,000 km (3,700 mi). Denser clouds of dust can be formed in stronger winds, moving across
4794-500: Is still being killed and eaten today despite its protected status. The white feathers of the bird are used for ceremonial purposes. There are important Dreaming stories associated with the bush turkey. A number of artists painting in the desert today paint bush turkey Dreaming . This means they have been given stories of the origins of the turkey in the Dreamtime and are entitled to tell this story and paint about it. Hunting of
4935-486: Is sufficient precipitation or meltwater from glaciers above. They are usually shallow and saline, and wind blowing over their surface can cause stress, moving the water over nearby low-lying areas. When the lakes dry up, they leave a crust or hardpan behind. This area of deposited clay, silt or sand is known as a playa . The deserts of North America have more than one hundred playas, many of them relics of Lake Bonneville which covered parts of Utah, Nevada and Idaho during
5076-682: Is the Atacama Desert . It is virtually devoid of life because it is blocked from receiving precipitation by the Andes mountains to the east and the Chilean Coast Range to the west. The cold Humboldt Current and the anticyclone of the Pacific are essential to keep the dry climate of the Atacama. The average precipitation in the Chilean region of Antofagasta is just 1 mm (0.039 in) per year. Some weather stations in
5217-450: Is the key to plant growth. It can only take place during the day as energy from the sun is required, but during the day, many deserts become very hot. Opening stomata to allow in the carbon dioxide necessary for the process causes evapotranspiration , and conservation of water is a top priority for desert vegetation. Some plants have resolved this problem by adopting crassulacean acid metabolism , allowing them to open their stomata during
5358-414: Is the largest extant flying land bird in Australia, this long-legged bird is the smallest species in the genus Ardeotis . The species is mostly terrestrial and usually seen walking slowly alone or in pairs. When disturbed, Australian bustards often adopt a cryptic pose with neck erect and bill pointed skywards. They may stalk gradually away or run if alarmed, taking flight as a last resort. When leaving
5499-431: Is the specializations of mammalian kidneys shown by desert-inhabiting species. Many examples of convergent evolution have been identified in desert organisms, including between cacti and Euphorbia , kangaroo rats and jerboas , Phrynosoma and Moloch lizards. Deserts present a very challenging environment for animals. Not only do they require food and water but they also need to keep their body temperature at
5640-528: Is very cold and carries little moisture so little precipitation occurs and what does fall, usually snow, is carried along in the often strong wind and may form blizzards, drifts and dunes similar to those caused by dust and sand in other desert regions. In Antarctica , for example, the annual precipitation is about 50 mm (2 in) on the central plateau and some ten times that amount on some major peninsulas. Based on precipitation alone, hyperarid deserts receive less than 25 mm (1 in) of rainfall
5781-694: The Atacama Desert . Deserts of this type are often long and narrow and bounded to the east by mountain ranges. They occur in Namibia , Chile , southern California and Baja California . Other coastal deserts influenced by cold currents are found in Western Australia , the Arabian Peninsula and Horn of Africa , and the western fringes of the Sahara. In 1961, Peveril Meigs divided desert regions on Earth into three categories according to
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5922-642: The Australian Government as an environmental planning tool in the 1990s, with IBRA7 defining "large geographically distinct bioregions based on common climate, geology, landform, native vegetation and species information". There are almost no tourist facilities, and the environment is harsh. Only the most experienced travellers, who know how to survive without help in the desert, should visit. Few roads are signposted. At Katjarra , there are two camping spots, with shed tanks and long-drop toilets , and Indigenous rangers are available to show tourists
6063-639: The Birriliburu Indigenous Protected Area (IPA), which stretches into the Gibson Desert, meaning that the land is looked after by its traditional owners. Most of the area is covered by hummock grasslands ( Triodia spp.), with a few eucalypts , acacias , grevilleas , and bloodwoods ( Corymbia chippendalei ) are found on sand hills. As of 2020 over 2000 plant taxa have been identified, with only two of these recognised as threatened species ; over 550 of these are in
6204-631: The Central Desert an Indigenous Protected Area in 2008, handing over management of the land to the traditional owners. The mountain was closed to the public, as part of the Birriliburu IPA, in 2008, which gave time to plan for future tourism and to do archaeological research and ecological surveys. The rock art and archaeological site at Karnatukul was given the name Serpent's Glen by dogger Peter Muir (father of artist and Indigenous rights activist Kado Muir ) in 1965, "on account of
6345-625: The Gibson Desert (156,300 km (60,300 sq mi), to the east), all of which lie within the huge Australian Arid Zone which covers the centre of the Australian continent . It lies east of the Pilbara region, and north of Gascoyne , and is part of the Western Desert. To the north the nearest large area identifiable is the Karlamilyi National Park . Its landforms, fauna and flora are all similar to
6486-580: The Martu people . There are also two smaller communities at Parnngurr and Punmu . Some of the landforms and locations within the LSD include: There is a high level of biodiversity among plants and animals, with some species threatened by various factors. Only around 4.6% of the Little Sandy Desert bioregion is within a protected area , much of which is managed as an Indigenous Protected Area ,
6627-418: The creator being sometimes termed the rainbow serpent , and it contains much ancient rock art . There are rock paintings of the bilby , the black-flanked rock-wallaby and a headdress made for ceremonial use , created using ochres and charcoal , and it is one of the largest such sites in Australia. Over 25,000 lithic artefacts have been located at the site. Katjarra is fairly close to Well 5 on
6768-621: The horse latitudes at 30° to 35° North and South. These belts are associated with the subtropical anticyclone and the large-scale descent of dry air. The Sahara Desert is of this type. Mid-latitude deserts occur between 30° and 50° North and South. They are mostly in areas remote from the sea where most of the moisture has already precipitated from the prevailing winds. They include the Tengger and Sonoran Deserts . Monsoon deserts are similar. They occur in regions where large temperature differences occur between sea and land. Moist warm air rises over
6909-542: The traditional owners of the land. Today the group recognised as traditional owners are the Martu people . The desert is crossed by the Canning Stock Route , an historic stock route created in the early 20th century. The Little Sandy Desert covers around 110,900 km (42,800 sq mi) and adjoins the Great Sandy Desert (110,900 km (42,800 sq mi), to the north) and
7050-417: The windward slope of the mountain range . When they descend on the leeward side, they warm and their capacity to hold moisture increases so an area with relatively little precipitation occurs. The Taklamakan Desert is an example, lying in the rain shadow of the Himalayas and receiving less than 38 mm (1.5 in) precipitation annually. Other areas are arid by virtue of being a very long way from
7191-492: The Atacama have never received rain. Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971. It is so arid that mountains that reach as high as 6,885 m (22,589 ft) are completely free of glaciers and, in the southern part from 25°S to 27°S, may have been glacier-free throughout the Quaternary , though permafrost extends down to an altitude of 4,400 m (14,400 ft) and
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#17327583238327332-442: The Birriliburu IPA, and 116 within the whole desert, including the Australian bustard ( Aredeotis australis ) and bush stone-curlew ( Burhinus grallariu ). Threatened animal species include: Threats to biodiversity include wildfires , feral animals , weeds, and uncontrolled grazing. Feral camels destroy water sources, and along with donkeys, horses and rabbits help destroy the ecosystem by overgrazing. feral cats have reduced
7473-490: The Canning Stock Route, and had been frequently visited by travellers and tourists; access had also opened up from Wiluna in the 1970s owing to pastoral leases and mining interests nearby, Over time, there had been loss of or damage to thousands of Aboriginal artefacts , including grinding stones . The federal government created an Indigenous Protected Area of 66,540 km (25,690 sq mi) of
7614-513: The Great Sandy Desert. The three deserts have low and highly variable rainfall, averaging 250–350 mm (9.8–13.8 in) annually, with most of it in summer. The median annual rainfall, based on the years 1890–2005, across the whole of the LSD is 178 mm (7.0 in). and are subject to extreme heat. The landscape is dominated by red sand dunes , sandstone mesas and rocky plains. The Rudall River has its headwaters in
7755-410: The LSD, flowing northeast into the southern Great Sandy Desert, where it occasionally empties into Lake Dora , an ephemeral salt lake . There are a few permanent water sources in the hills, and some waterholes left by the Canning Stock Route. The town of Jigalong is on the western edge of the desert, with a population of approximately 300 in 2016. The traditional owners of this area are recognised as
7896-532: The absence of available water) the actual evapotranspiration may be close to zero. Semi-deserts are regions which receive between 250 and 500 mm (10 and 20 in) and when clad in grass, these are known as steppes . Most deserts on Earth such as the Sahara Desert , Grand Australian Desert and the Great Basin Desert , occur in low altitudes . One of the driest places on Earth
8037-401: The air but soon fall back to earth, ejecting other particles in the process. Their weight prevents them from being airborne for long and most only travel a distance of a few meters (yards). The sand streams along above the surface of the ground like a fluid, often rising to heights of about 30 cm (12 in). In a really severe steady blow, 2 m (6 ft 7 in) is about as high as
8178-473: The amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks , which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and
8319-722: The amount of precipitation they received. In this now widely accepted system, extremely arid lands have at least twelve consecutive months without precipitation, arid lands have less than 250 mm (9.8 in) of annual precipitation, and semiarid lands have a mean annual precipitation of between 250 and 500 mm (9.8 and 19.7 in). Both extremely arid and arid lands are considered to be deserts while semiarid lands are generally referred to as steppes when they are grasslands. Deserts are also classified, according to their geographical location and dominant weather pattern, as trade wind, mid-latitude, rain shadow, coastal, monsoon, or polar deserts . Trade wind deserts occur either side of
8460-411: The barren rock is to be found in the so-called Dry Valleys of Antarctica that almost never get snow, which can have ice-encrusted saline lakes that suggest evaporation far greater than the rare snowfall due to the strong katabatic winds that even evaporate ice. Deserts, both hot and cold, play a part in moderating Earth's temperature, because they reflect more of the incoming light and their albedo
8601-531: The bay was named in honor of the bird. Bustard Head, at the Northern end of the bay, is the site of the first lighthouse erected in Queensland (1868). Barossa Valley winery Turkey Flat takes its name from the Australian bustard. 'Turkey Flat' was the local name given to Lot 1, 100 of Moorooroo (where the winery now sits) on settlement in reference to the large flocks of the Australian bustard found along
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#17327583238328742-409: The bird are seen during the breeding season. The habits of the bird are usually discreet and shy of disturbance, however, the display of males during the breeding season is a conspicuous performance that is accompanied by loud booming. The male is able to expand a sac at the neck to display their longer feathers as a swaying skirt, with the head held proud and upward facing, the wings are pointed toward
8883-647: The bird is kere artewe , and the Luritja name is kipara . The Larrakia name is danimila . The species is also presumed to be important to the Noongar peoples, whose names for the bird included the word bebilya , recorded by John Gilbert and published in Birds of Australia (Gould, 1848). The only Australian species of Ardeotis , a genus occurring in the African, Indian and Australasian regions, this bustard
9024-470: The bush turkey was noted as difficult, the elusive habits requiring a lot of manoeuvring for a clear target, but greater success was found by the colonists, first from horseback and later from motor vehicles. The bustard was protected by legislation introduced during the later nineteenth century, which included closed seasons for hunting and eventually a prohibition on shooting. The value of the species to agriculture, arriving to control outbreaks of grasshoppers,
9165-457: The capture of large quantities of solar energy . English desert and its Romance cognates (including Italian and Portuguese deserto , French désert and Spanish desierto ) all come from the ecclesiastical Latin dēsertum (originally "an abandoned place"), a participle of dēserere , "to abandon". The correlation between aridity and sparse population is complex and dynamic, varying by culture, era, and technologies; thus
9306-523: The cellular structure of which has been modified to allow them to store water. When rain falls, the water is rapidly absorbed by the shallow roots and retained to allow them to survive until the next downpour, which may be months or years away. The giant saguaro cacti of the Sonoran Desert form "forests", providing shade for other plants and nesting places for desert birds. Saguaro grows slowly but may live for up to two hundred years. The surface of
9447-615: The coldest part of the year. Animals adapted to live in deserts are called xerocoles . There is no evidence that body temperature of mammals and birds is adaptive to the different climates, either of great heat or cold. In fact, with a very few exceptions, their basal metabolic rate is determined by body size, irrespective of the climate in which they live. Many desert animals (and plants) show especially clear evolutionary adaptations for water conservation or heat tolerance and so are often studied in comparative physiology , ecophysiology , and evolutionary physiology . One well-studied example
9588-597: The collision between airborne particles and by the impacts of saltating sand grains landing on the ground. The mechanism is little understood but the particles usually have a negative charge when their diameter is under 250 μm and a positive one when they are over 500 μm. Deserts and semi-deserts are home to ecosystems with low or very low biomass and primary productivity in arid or semi-arid climates. They are mostly found in subtropical high-pressure belts and major continental rain shadows . Primary productivity depends on low densities of small photoautotrophs that sustain
9729-519: The colonies in New South Wales; Gould described the flesh as delicate and well-flavoured. Bustard Bay, on Queensland's Discovery Coast, was named by Lt. James Cook, who anchored the Endeavour there on 23rd May 1770. The next day, he made his second Australian landing, at the location now known as Seventeen Seventy. While investigating the area, Cook's party shot and killed a bustard. It was declared "the best bird we had eaten since we left England" and
9870-586: The color of the underlying surface. The desert lark takes frequent dust baths which ensures that it matches its environment. Water and carbon dioxide are metabolic end products of oxidation of fats, proteins, and carbohydrates. Oxidising a gram of carbohydrate produces 0.60 grams of water; a gram of protein produces 0.41 grams of water; and a gram of fat produces 1.07 grams of water, making it possible for xerocoles to live with little or no access to drinking water. The kangaroo rat for example makes use of this water of metabolism and conserves water both by having
10011-468: The concept of desert, without the characteristic of aridity, not lacking water, but instead lacking life. Such places can be so-called "ocean deserts", which are mostly at the centers of gyres , but also hypoxic or anoxic waters such as dead zones . Deserts usually have a large diurnal and seasonal temperature range, with high daytime temperatures falling sharply at night. The diurnal range may be as much as 20 to 30 °C (36 to 54 °F) and
10152-508: The desert floor to scarify the seed coat. The seed of the mesquite tree, which grows in deserts in the Americas, is hard and fails to sprout even when planted carefully. When it has passed through the gut of a pronghorn it germinates readily, and the little pile of moist dung provides an excellent start to life well away from the parent tree. The stems and leaves of some plants lower the surface velocity of sand-carrying winds and protect
10293-500: The desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles , and often spines to deter herbivory . Some annual plants germinate , bloom and die in the course of a few weeks after rainfall, while other long-lived plants survive for years and have deep root systems able to tap underground moisture. Animals need to keep cool and find enough food and water to survive. Many are nocturnal , and stay in
10434-704: The desertification occurred as the polar ice sheets expanded. In 2014, the Birriliburu traditional owners and rangers reopened Katjarra for the month of July, with the hope of opening it to the public each July in the future. Permits were issued for 70 visitors, with an access fee of $ 100 access fee per vehicle. It was also hoped that more Aboriginal people, especially young people, would visit to reconnect with their culture. [REDACTED] Media related to Little Sandy Desert at Wikimedia Commons 25°16′S 121°52′E / 25.26°S 121.86°E / -25.26; 121.86 Desert A desert
10575-587: The driest season, and others curl their leaves up to reduce transpiration. Others, such as aloes , store water in succulent leaves or stems or in fleshy tubers. Desert plants maximize water uptake by having shallow roots that spread widely, or by developing long taproots that reach down to deep rock strata for ground water. The saltbush in Australia has succulent leaves and secretes salt crystals, enabling it to live in saline areas. In common with cacti, many have developed spines to ward off browsing animals. Some desert plants produce seed which lies dormant in
10716-455: The external temperature. Jerboas , desert rats , kangaroo rats and other small rodents emerge from their burrows at night and so do the foxes, coyotes, jackals and snakes that prey on them. Kangaroos keep cool by increasing their respiration rate, panting, sweating and moistening the skin of their forelegs with saliva . Mammals living in cold deserts have developed greater insulation through warmer body fur and insulating layers of fat beneath
10857-463: The family Otididae has been variously assigned. Gray recognised the species in the genus Otis in the first description, Gregory Mathews later proposed the names Choriotis and Austrotis , along with subspecific descriptions, and it was placed as a species of Eupodotis in the mid-twentieth century. Common names for Ardeotis australis include bustard, Australian bustard, plains turkey, wild turkey and native turkey. The Arrernte name for
10998-521: The fine material has been blown away and the surface consists of a mosaic of smooth stones, often forming desert pavements , and little further erosion takes place. Other desert features include rock outcrops , exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate. There may be underground sources of water, in the form of springs and seepages from aquifers . Where these are found, oases can occur. Plants and animals living in
11139-572: The form of springs , aquifers , underground rivers or lakes. Where these lie close to the surface, wells can be dug and oases may form where plant and animal life can flourish. The Nubian Sandstone Aquifer System under the Sahara Desert is the largest known accumulation of fossil water . The Great Man-Made River is a scheme launched by Libya's Muammar Gaddafi to tap this aquifer and supply water to coastal cities. Kharga Oasis in Egypt
11280-458: The fragmentation of harder granites , limestone and sandstone . There is a certain critical size (about 0.5 mm) below which further temperature-induced weathering of rocks does not occur and this provides a minimum size for sand grains. As the mountains are eroded, more and more sand is created. At high wind speeds, sand grains are picked up off the surface and blown along, a process known as saltation . The whirling airborne grains act as
11421-459: The greater range of those inhabiting more arid regions. The birds may become locally abundant after land clearing or during outbreaks of grasshoppers. The greatest fidelity to a local region is reported in areas of high rainfall in the north and northwest of Australia. The habitat favoured by the species is open grasslands, perhaps with some trees, spinifex plains and low shrublands. This bustard will enter denser areas of vegetation after fire, and
11562-463: The ground and tail feathers arched over the back; they stride about an area while adopting this posture and emit deep roaring noises. The voice of the courting male has been transliterated as "who-o-o-o". Males have been observed in close proximity during territorial disputes, using the breeding display and call to challenge each other, but the direct conflict seen in smaller bustard species is rare with this bird. One incident involving physical combat at
11703-439: The ground from erosion. Even small fungi and microscopic plant organisms found on the soil surface (so-called cryptobiotic soil ) can be a vital link in preventing erosion and providing support for other living organisms. Cold deserts often have high concentrations of salt in the soil. Grasses and low shrubs are the dominant vegetation here and the ground may be covered with lichens . Most shrubs have spiny leaves and shed them in
11844-474: The ground have a marked effect on the degree of aridity and the plant and animal life that can be sustained. Rain falling in the cold season may be more effective at promoting plant growth, and defining the boundaries of deserts and the semiarid regions that surround them on the grounds of precipitation alone is problematic. A semi-arid desert or a steppe is a version of the arid desert with much more rainfall, vegetation and higher humidity. These regions feature
11985-432: The ground on its long legs, stopping periodically to snatch up insects. Like other desert birds, it is well-camouflaged by its coloring and can merge into the landscape when stationary. The sandgrouse is an expert at this and nests on the open desert floor dozens of kilometers (miles) away from the waterhole it needs to visit daily. Some small diurnal birds are found in very restricted localities where their plumage matches
12126-427: The ground rises quickly through a small pocket of cooler, low-pressure air above forming a whirling column of particles, a dust devil . Sandstorms occur with much less frequency than dust storms. They are often preceded by severe dust storms and occur when the wind velocity increases to a point where it can lift heavier particles. These grains of sand, up to about 0.5 mm (0.020 in) in diameter are jerked into
12267-443: The ground they take to the air with heavy beats of the wings. A brooding female will crouch and move away if disturbed, flightless juveniles will remain still and rely on the camouflage of their plumage to evade detection. Despite the apparent labour in flying, they have strength and stamina that allows them to travel long distances. The roost is at a high point on an open plain or in trees when they are available. Greater numbers of
12408-429: The high desert floor, creating canyons that are over a mile (6,000 feet or 1,800 meters) deep in places, exposing strata that are over two billion years old. Sand and dust storms are natural events that occur in arid regions where the land is not protected by a covering of vegetation. Dust storms usually start in desert margins rather than the deserts themselves where the finer materials have already been blown away. As
12549-783: The high elevations of the Tabernas Desert (and some parts of the Spanish Plateu ), The Sahel , The Eurasian Steppe , most of Central Asia , the Western US , most of Northern Mexico , portions of South America (especially in Argentina ) and the Australian Outback . They usually feature BSh (hot steppe) or BSk (temperate steppe) in the Köppen climate classification . Coastal deserts are mostly found on
12690-454: The import of water from an outside source. Many trade routes have been forged across deserts, especially across the Sahara , and traditionally were used by caravans of camels carrying salt, gold, ivory and other goods. Large numbers of slaves were also taken northwards across the Sahara. Some mineral extraction also takes place in deserts, and the uninterrupted sunlight gives potential for
12831-523: The lack of heat to aid in the evaporation process. Deserts are sometimes classified as "hot" or "cold", "semiarid" or "coastal". The characteristics of hot deserts include high temperatures in summer; greater evaporation than precipitation, usually exacerbated by high temperatures, strong winds and lack of cloud cover; considerable variation in the occurrence of precipitation, its intensity and distribution; and low humidity. Winter temperatures vary considerably between different deserts and are often related to
12972-483: The land with a billowing leading edge. The sunlight can be obliterated and it may become as dark as night at ground level. In a study of a dust storm in China in 2001, it was estimated that 6.5 million tons of dust were involved, covering an area of 134,000,000 km (52,000,000 sq mi). The mean particle size was 1.44 μm. A much smaller scale, short-lived phenomenon can occur in calm conditions when hot air near
13113-476: The land, deposits its water content and circulates back to sea. Further inland, areas receive very little precipitation. The Thar Desert near the India/Pakistan border is of this type. In some parts of the world, deserts are created by a rain shadow effect. Orographic lift occurs as air masses rise to pass over high ground. In the process they cool and lose much of their moisture by precipitation on
13254-414: The large number of snake drawings hereabouts and their obvious association with Aboriginal legends of Rainbow Serpents". The site was, until recently, estimated to have been inhabited for up to 25,000 years, and known as the site of the oldest continuous recorded occupation in the Western Desert cultural region . The Martu people used to congregate at Katjarra when other water sources had dried up. However,
13395-723: The last ice age when the climate was colder and wetter. These include the Great Salt Lake , Utah Lake , Sevier Lake and many dry lake beds. The smooth flat surfaces of playas have been used for attempted vehicle speed records at Black Rock Desert and Bonneville Speedway and the United States Air Force uses Rogers Dry Lake in the Mojave Desert as runways for aircraft and the Space Shuttle . Deserts have been defined and classified in
13536-510: The life processes of plants. Potential evapotranspiration , then, is the amount of water that could evaporate in any given region. As an example, Tucson, Arizona receives about 300 mm (12 in) of rain per year, however about 2,500 mm (98 in) of water could evaporate over the course of a year. In other words, about eight times more water could evaporate from the region than actually falls as rain. Rates of evapotranspiration in cold regions such as Alaska are much lower because of
13677-412: The location of the desert on the continental landmass and the latitude. Daily variations in temperature can be as great as 22 °C (40 °F) or more, with heat loss by radiation at night being increased by the clear skies. Cold deserts, sometimes known as temperate deserts, occur at higher latitudes than hot deserts, and the aridity is caused by the dryness of the air. Some cold deserts are far from
13818-413: The males. The abdomen is white and separated from the light grey of the neck by a black band of feathers. The wing coverts are patchily coloured with black and white patterning, which is visible while at rest or especially in flight. The iris is white, and their beak is variously whitish to brown in colour. The legs are long and yellow to cream coloured. Males are up to 1.2 m (47 in) tall with
13959-404: The measurement of precipitation in providing a scientific measurement-based definition of a desert. The water budget of an area can be calculated using the formula P − PE ± S , wherein P is precipitation, PE is potential evapotranspiration rates and S is the amount of surface storage of water. Evapotranspiration is the combination of water loss through atmospheric evaporation and through
14100-436: The mottled black and brown coloration of their downy plumage to evade detection by squatting and remaining motionless. Brooding females may be driven from the egg by the raptor Hamirostra melanosternon , the blackbreasted kite, who are able to throw or drop stones to break the shell and feed on the contents; the kite is also known to carry the broken shell to its nest. The species is strongly attracted to capers, fruit of
14241-617: The nearest available sources of moisture. Montane deserts are arid places with a very high altitude ; the most prominent example is found north of the Himalayas, in the Kunlun Mountains and the Tibetan Plateau . Many locations within this category have elevations exceeding 3,000 m (9,800 ft) and the thermal regime can be hemiboreal . These places owe their profound aridity (the average annual precipitation
14382-409: The night to allow CO 2 to enter, and close them during the day, or by using C4 carbon fixation . Many desert plants have reduced the size of their leaves or abandoned them altogether. Cacti are present in both North and South America with a post-Gondwana origin. The genus is desert specialist, and in most species, the leaves have been dispensed with and the chlorophyll displaced into the trunks,
14523-527: The ocean and others are separated by mountain ranges from the sea, and in both cases, there is insufficient moisture in the air to cause much precipitation. The largest of these deserts are found in Central Asia. Others occur on the eastern side of the Rocky Mountains , the eastern side of the southern Andes and in southern Australia. Polar deserts are a particular class of cold desert. The air
14664-426: The outer surfaces of rocks split off in flat flakes. This is believed to be caused by the stresses put on the rock by repeated thermal expansions and contractions which induces fracturing parallel to the original surface. Chemical weathering processes probably play a more important role in deserts than was previously thought. The necessary moisture may be present in the form of dew or mist. Ground water may be drawn to
14805-514: The part of the range that is open to the public. Mining for copper and gold, and some exploration for uranium , are the main economic activities. There is limited grazing for stock animals in the east. The Carnarvon Range(s), known as Katjarra to the Martu people, covers around 2,000 km (770 sq mi). It is a sacred and significant place for the Indigenous people, associated with
14946-466: The pavement is formed. It may be that after the sand and dust is blown away by the wind the stones jiggle themselves into place; alternatively, stones previously below ground may in some way work themselves to the surface. Very little further erosion takes place after the formation of a pavement, and the ground becomes stable. Evaporation brings moisture to the surface by capillary action and calcium salts may be precipitated, binding particles together to form
15087-407: The plant Capparis nummularia known as myandee or moonflower in the Australian northwest, and this behaviour is exploited by Indigenous peoples who dig pit traps around the bush and wait nearby to capture them. The omnivorous diet includes seeds and fruit of plants, a variety of insects, especially grasshoppers, lizards, young birds and small rodents. The distribution range of the species includes
15228-537: The populations of bilbies and mulgara . Foxes are the main threats to mammals. Buffel grass threatens the native plant species, as it is tough, and burns hotter in the ever more frequent bushfires caused by climate change . Bush Heritage Australia has done some plant and animal surveys in Katjarra . The Little Sandy Desert (LSD) is an interim Australian bioregion no. 63, covering 11,089,857 km (4,281,818 sq mi). The biogregions were developed by
15369-465: The recovery and future management of this species has been prepared. On the 2007 advisory list of threatened vertebrate fauna in Victoria the species is listed as critically endangered , maintaining this advice in the listing published in 2016. Australian Aboriginals generally refer to this bird as the bush turkey. It is an important food source for Aboriginal people from Central Australia , and
15510-445: The region stated that the species avoided human habitation and pastoral activities, and that over-hunting or land clearing rather than foxes were responsible for their local disappearance. The incidence of historical occurrence in southwest Australia was year round, and sometimes in large flocks. This bird remains relatively common and widespread across most of northern Australia (see Atlas) , but its range appears to have contracted in
15651-546: The resulting fragments and rubble strewn over the desert floor are further eroded by the wind. This picks up particles of sand and dust, which can remain airborne for extended periods – sometimes causing the formation of sand storms or dust storms . Wind-blown sand grains striking any solid object in their path can abrade the surface. Rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes . Other deserts are flat, stony plains where all
15792-438: The rock surface experiences even greater temperature differentials. During the day the sky is usually clear and most of the sun 's radiation reaches the ground, but as soon as the sun sets, the desert cools quickly by radiating heat into space. In hot deserts, the temperature during daytime can exceed 45 °C (113 °F) in summer and plunge below freezing point at night during winter. Such large temperature variations have
15933-503: The sand stream can rise as the largest sand grains do not become airborne at all. They are transported by creep, being rolled along the desert floor or performing short jumps. During a sandstorm, the wind-blown sand particles become electrically charged . Such electric fields , which range in size up to 80 kV/m, can produce sparks and cause interference with telecommunications equipment. They are also unpleasant for humans and can cause headaches and nausea. The electric fields are caused by
16074-435: The shade or underground during the heat of the day. They tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine . Some animals remain in a state of dormancy for long periods, ready to become active again during the rare rainfall. They then reproduce rapidly while conditions are favorable before returning to dormancy. People have struggled to live in deserts and
16215-441: The sheet consists of thin horizontal layers of coarse silt and very fine to medium grain sand, separated by layers of coarse sand and pea-gravel which are a single grain thick. These larger particles anchor the other particles in place and may also be packed together on the surface so as to form a miniature desert pavement. Small ripples form on the sand sheet when the wind exceeds 24 km/h (15 mph). They form perpendicular to
16356-437: The skin and various thermoregulatory strategies to maintain its body temperature in one of the harshest environments on Earth. Australian bustard The Australian bustard ( Ardeotis australis ) is a large ground-dwelling bird that is common in grassland, woodland and open agricultural country across northern Australia and southern New Guinea . It stands at about one metre (3 ft 3 in) high, and its wingspan
16497-412: The skin. The arctic weasel has a metabolic rate that is two or three times as high as would be expected for an animal of its size. Birds have avoided the problem of losing heat through their feet by not attempting to maintain them at the same temperature as the rest of their bodies, a form of adaptive insulation. The emperor penguin has dense plumage, a downy under layer, an air insulation layer next to
16638-466: The soil until sparked into growth by rainfall. With annuals , such plants grow with great rapidity and may flower and set seed within weeks, aiming to complete their development before the last vestige of water dries up. For perennial plants, reproduction is more likely to be successful if the seed germinates in a shaded position, but not so close to the parent plant as to be in competition with it. Some seed will not germinate until it has been blown about on
16779-425: The southeast of the continent during the last century, perhaps due to hunting (now illegal except for indigenous Australians), feral predators such as pigs and foxes ( Vulpes vulpes ) and habitat destruction . The species is very sensitive to disturbance at its breeding sites by humans or cattle and sheep and will desert an area in response. Its nomadic habits make it difficult to assess. In 2012 IUCN downlisted
16920-411: The southern LSD, including 16 species of conservation significance. The bark of the birdflower is used by local people to make belts and sandals, while the spear tree is used for making spears for men and digging sticks for women. There are many reptiles and birds species, but many small- to medium-sized mammals have gone extinct, and many are threatened. There have been 103 bird species recorded in
17061-464: The sparse vegetation cover and the activities of large mammals and people. Plants and animals in deserts are mostly adapted to extreme and prolonged water deficits , but their reproductive phenology often responds to short episodes of surplus. Competitive interactions are weak. Plants face severe challenges in arid environments. Problems they need to solve include how to obtain enough water, how to avoid being eaten and how to reproduce. Photosynthesis
17202-549: The species to Least Concern . The assessment of IUCN in 2016 maintained its status as least concern, but noted a declining population trajectory. The total population is thought to exceed 10 000 and be no greater than 100 000 individuals. The Australian bustard is not listed as threatened on the Environment Protection and Biodiversity Conservation Act 1999 . Ardeotis australis is listed in state conservation registers, providing evaluation and protection to
17343-548: The species under each region's legislation. In Western Australia and the Northern Territory the classification is near threatened by extinction, the states of South Australia and New South Wales record it as endangered, and the status of least concern in Queensland. The Australian bustard is listed as threatened on the Victorian Flora and Fauna Guarantee Act 1988. Under this Act, an Action Statement for
17484-440: The surface by evaporation and the formation of salt crystals may dislodge rock particles as sand or disintegrate rocks by exfoliation. Shallow caves are sometimes formed at the base of cliffs by this means. As the desert mountains decay, large areas of shattered rock and rubble occur. The process continues and the end products are either dust or sand. Dust is formed from solidified clay or volcanic deposits whereas sand results from
17625-464: The surface of the ground. Dunes are sometimes solitary, but they are more often grouped together in dune fields. When these are extensive, they are known as sand seas or ergs . The shape of the dune depends on the characteristics of the prevailing wind. Barchan dunes are produced by strong winds blowing across a level surface and are crescent-shaped with the concave side away from the wind. When there are two directions from which winds regularly blow,
17766-577: The surrounding mountains. Former desert areas presently in non-arid environments, such as the Sandhills in Nebraska , are known as paleodeserts. In the Köppen climate classification system, deserts are classed as BWh (hot desert) or BWk (temperate desert). In the Thornthwaite climate classification system , deserts would be classified as arid megathermal climates. Polar deserts are
17907-610: The surrounding semi-arid lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, and oases have provided opportunities for a more settled way of life. The cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Desert farming is possible with the aid of irrigation , and the Imperial Valley in California provides an example of how previously barren land can be made productive by
18048-399: The tallest type of dune. Rounded mounds of sand without a slip face are the rare dome dunes, found on the upwind edges of sand seas. In deserts where large amounts of limestone mountains surround a closed basin , such as at White Sands National Park in south-central New Mexico , occasional storm runoff transports dissolved limestone and gypsum into a low-lying pan within the basin where
18189-407: The trunk is folded like a concertina , allowing it to expand, and a large specimen can hold eight tons of water after a good downpour. Other xerophytic plants have developed similar strategies by a process known as convergent evolution . They limit water loss by reducing the size and number of stomata, by having waxy coatings and hairy or tiny leaves. Some are deciduous, shedding their leaves in
18330-496: The use of the word desert can cause confusion. In English before the 20th century, desert was often used in the sense of "unpopulated area", without specific reference to aridity ; but today the word is most often used in its climate-science sense (an area of low precipitation). Phrases such as " desert island " and " Great American Desert ", or Shakespeare 's "deserts of Bohemia " ( The Winter's Tale ) in previous centuries did not necessarily imply sand or aridity; their focus
18471-416: The water evaporates, depositing the gypsum and forming crystals known as selenite . The crystals left behind by this process are eroded by the wind and deposited as vast white dune fields that resemble snow-covered landscapes. These types of dune are rare, and only form in closed arid basins that retain the highly soluble gypsum that would otherwise be washed into the sea. A large part of the surface area of
18612-476: The western edges of continental land masses in regions where cold currents approach the land or cold water upwellings rise from the ocean depths. The cool winds crossing this water pick up little moisture and the coastal regions have low temperatures and very low rainfall, the main precipitation being in the form of fog and dew. The range of temperatures on a daily and annual scale is relatively low, being 11 °C (20 °F) and 5 °C (9 °F) respectively in
18753-583: The whole history of the site, confirming its status as the oldest known site of continuous occupation in the Western Desert. The wood was used as firewood, food, bush medicine and for making tools, from the Pleistocene through to the Holocene eras, and more than 100 species were used across the continent by other Aboriginal peoples . Karnakatul shows one of the earliest uses of firewood, and habitation continued through times of extreme climate change, when
18894-404: The wind blows, saltation and creep take place on the windward side of the dune and individual grains of sand move uphill. When they reach the crest, they cascade down the far side. The upwind slope typically has a gradient of 10° to 20° while the lee slope is around 32°, the angle at which loose dry sand will slip. As this wind-induced movement of sand grains takes place, the dune moves slowly across
19035-511: The wind direction and gradually move across the surface as the wind continues to blow. The distance between their crests corresponds to the average length of jumps made by particles during saltation. The ripples are ephemeral and a change in wind direction causes them to reorganise. Sand dunes are accumulations of windblown sand piled up in mounds or ridges. They form downwind of copious sources of dry, loose sand and occur when topographic and climatic conditions cause airborne particles to settle. As
19176-450: The world's deserts consists of flat, stone-covered plains dominated by wind erosion. In " eolian deflation ", the wind continually removes fine-grained material, which becomes wind-blown sand. This exposes coarser-grained material, mainly pebbles with some larger stones or cobbles , leaving a desert pavement , an area of land overlaid by closely packed smooth stones forming a tessellated mosaic. Different theories exist as to how exactly
19317-477: The world, around 20% of desert is sand, varying from only 2% in North America to 30% in Australia and over 45% in Central Asia. Where sand does occur, it is usually in large quantities in the form of sand sheets or extensive areas of dunes . A sand sheet is a near-level, firm expanse of partially consolidated particles in a layer that varies from a few centimeters to a few meters thick. The structure of
19458-592: Was 14.5 kg (32 lb), a specimen obtained in Victoria. Reports of large birds, presumably males, were given by Tom Carter in the west (16 lb), a recorded range of 16–18 lb by E. F. Boehm in South Australia was exceeded in some specimens (28 lb). The smaller specimens in records are of an unwell adult weighing 9 lb, shot by Carter at Broomehill , and a healthy but small specimen of 7½ lb captured and weighed by Dominic Serventy and Hubert Whittell at Bridgetown in 1949. Although it
19599-436: Was acknowledged and promoted to discourage the continued hunting of the bird. Aboriginal peoples were exempted from any prohibition on hunting. The illegal hunting of the bustard continued during the twentieth century. John Gould's early description of the bustard noted the difficulty of shooting of the bird due to their wariness around settled regions, but he was able to stalk and kill the bird more easily in areas remote from
19740-576: Was held in the General T. Davies collection. The whereabouts of that type is now unknown, after being sold to a private buyer. John Gould also provided a description in 1841, and named the bird Otis australasianus , using a skin obtained in Western Australia. That specimen was later nominated as the syntype and is held at the Academy of Natural Sciences of Philadelphia . Placement within
19881-459: Was the sparse population. Deserts occupy about one third of Earth's land surface. Bottomlands may be salt -covered flats. Eolian processes are major factors in shaping desert landscapes. Polar deserts (also seen as "cold deserts") have similar features, except the main form of precipitation is snow rather than rain. Antarctica is the world's largest cold desert (composed of about 98% thick continental ice sheet and 2% barren rock). Some of
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