Thar Desert
The Thar Desert, also known as the Great Indian Desert, is a vast arid region located primarily in Rajasthan, India, extending into parts of Pakistan. Covering over 77,000 square miles (200,000 square kilometers), it features a diverse landscape comprising sand dunes, stony hills, and intermittent river terraces, with the Luni River flowing through it toward the Arabian Sea. The climate is characterized by extreme temperatures, with daytime highs reaching up to 120°F (49°C) and nighttime lows dropping to 32°F (0°C). Rainfall is scarce, averaging about 1 inch (25 millimeters) annually, and occurs mainly during the monsoon months from June to September.
Ecologically, the Thar Desert supports a variety of unique flora and fauna, including drought-resistant plant species and endemic scrub species. The region is home to significant wildlife, such as the great Indian bustard and the chinkara, as well as various reptiles and mammals adapted to the harsh conditions. Human populations largely rely on nomadic herding and farming of drought-resistant crops, with the camel playing a central role in transportation and sustenance.
However, the Thar Desert faces environmental challenges, including drought, climate change, and habitat degradation, which threaten its biodiversity and the livelihoods of its inhabitants. Conservation efforts are ongoing, particularly within the Desert National Park, which is crucial for protecting the unique species and ecosystems of this remarkable desert landscape.
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Subject Terms
Thar Desert
- Category: Desert Biomes.
- Geographic Location: Asia.
Summary: One of the deserts in the Rajasthan region in India, the Thar Desert hosts a remarkable suite of valuable flora, as well as some vulnerable fauna.
The Thar Desert, also called the Great Indian Desert, is primarily located in Rajasthan, India, but extends along the borderlands of Pakistan and India between the Indus River to its west, the Sutlej River to its northwest, the Aravali Mountains to its east, and the salty marshland of the Rann of Kutch to the south. The desert covers an area of more than 77,000 square miles (200,000 square kilometers) of mostly barren land, but also features the Luni River, which cuts through the desert on its way to the Arabian Sea.
Level to gently sloping plains are broken by dune fields and low, barren hills; these are interspersed with sandy depressions, and some river terraces and flood plains. A thick series of sedimentary rocks here comprise sandstone, limestone, and shales; the Thar Desert is known as a source of marble and limestone that are widely used in India and exported to other countries as construction material. As a foundation for habitats, the region can be divided into major sand dunes, sandy plains, stony hill areas, generally textured and compact soil lands, and saline terrain.
The arid climate is harsh: Annual rainfall averages a scant 1 inch (25 millimeters), although it can range up to 4–20 inches (100–500 millimeters), because of the unpredictability of the monsoon effects across the region. Most of the rain here falls in the monsoon months, from June to September; winter rains are insignificant. Extremely high temperatures assure very high evaporation rates. Daytime temperatures reach a very hot 120 F (49 C)—and occasionally 124 F (51 C)—but also can dip to a low of 32 F (0 C) at night during December and January. The Thar Desert is sometimes locally called Marusthali, meaning “the region of death.”
The precious rains play a vital role in the life of all parts of the Thar Desert; the water in many places deposits in tobas, or small ponds, that are the only source of surface water for animals and humans in most parts of the desert. For this reason, much of the population lives as nomads. When a toba dries up, these pastoralists gather their tough grazing herds and seek out the next toba. Diversion of water from the Luni River, along with well water, does support agriculture in some areas of the Thar Desert. Chief crops are barja, or pearl millet; jowar, or coarse millet; moong, or pigeon pea; til, or lentil seeds; moth, a legume; and matira, a type of melon.
Biodiversity
Ecologically, most of the desert’s vegetation is considered thorn forest or scrub forest. Although vegetation is sparsely distributed, there is a surprisingly large number of plant species with high economic and ecological value. In fact, important soil-binder species of grasses found in this region have been widely used by ecologists for the eco-restoration of degraded lands around the world. Xerophilous, or drought-adapted, grasses of the biome include Aristida adscensionis, Lasiurus scindicus, and Cenchrus biflorus. Among the small trees are Acacia nilotica, Tamarix aphylla, and Prosopis cineraria. Scrub species include Calligonum polygonoides, Crotalaria spp., and Haloxylon recurvum—all endemic to the Thar Desert, that is, found nowhere else.
Species having commercial importance by yielding fibers for cottage industries or larger textile concerns include khimp (Leptadenia pyrotechnica), munja (Saccharum bengalense), mudar (Calotropis procera), and Acacia jacquemontii. Natural dyes are extracted from thumba or bitter apple (Citrullus colocynthis). Matira or watermelon (C. lanatus) yields non-edible oil for the soap industry.
Famine food plants providing grain are Cenchrus biflorus, Panicum turgidum, and Panicum antidotale. Plants of medicinal value include isabgol (Plantago ovate) and gugul (Commiphora wightii).
In the extreme west of the region, there is hardly any tree cover, except for the “king of desert trees,” the khejri (Prosopis cineraria), which grows only near wells. It is only in this area where also are naturally found the Rajasthan state bird, the great Indian bustard (Ardeotis nigriceps); state animal, the chinkara or Indian gazelle (Gazella bennettii), and state flower, the rohida (Tecomella undulata).
The desert hosts some important reptile species, including the Indian spiny-tailed lizard (Uromastyx hardwickii), dwarf gecko (Tropiocolotes persicus euphorbiacola), Persian gecko (Hemidactylus persicus), desert monitor (Varanus griseus), and saw-scaled viper (Echis carinatus sochureki).
Among the mammals found in the area are desert fox (Vulpes vulpes), Indian or Bengal fox (Vulpes bengalensis), Indian desert cat (Felis silvestris ornata), hairy-footed gerbil (Gerbillus gleadowi), desert hare (Lepus tibetanus), and long-eared hedgehog (Hemiechinus auritus). The human populations of the region have domesticated the camel (Camelus dromedarius), upon which they are widely dependent for transportation and other purposes.
Conservation and Threats
The Desert National Park (DNP) covers an area of 1,220 square miles (3,162 square kilometers), split between the Jaisalmer and Barmer Districts of Rajasthan State. More than 100 bird species found in the DNP include a good population of the great Indian bustard, which is locally called godawan. The park also provides vital support for the migratory Houbara bustard (Chlamydotis undulata).
In the Thar Desert, persistent environmental concerns include drought, dust storms, searing temperatures, and the viability of the land to support fauna, flora, and human populations. During the extreme dry spells, herd animals are sold off, and soil is challenged to yield enough vegetation to support the food web.
The region’s biodiversity and ecology are continually threatened by climate change. The India Meteorological Department (IMD) reported that Rajasthan and most of western India experienced a significant increase in rainfall in the first two decades of the twenty-first century. In India and Pakistan’s semi-arid northwest regions, rainfall increased by more than 1050 percent from 1901 to 2015. Monsoon patterns also continue shifting. This rain impacts the plants and animals living in the region. For example, the number of Indian wolves decreased by 50 percent between 2010 and 2020.
Bibliography
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