摘要: Description　　N 25 51 to N 26 52 and E 70 18 to E 70 34　　The Thar Desert in north-western India is a unique and the only habitat of its type in the Indian subcontinent. The Aravalli hills mark the east

Description

　　N 25 51 to N 26 52 and E 70 18 to E 70 34

　　The Thar Desert in north-western India is a unique and the only habitat of its type in the Indian subcontinent. The Aravalli hills mark the eastern-most boundary limit of the Thar desert while the western limit is defined by the fertile plains of the Indus. The Great Rann of Kutch forms a sharp boundary in the south while its northern limits are formed by the riparian sub-Himalayan plains. The Desert National Park (DNP) covers an area of 3162 km2 of which 1900 km2 is in Jaisalmer district and remaining 1262 km2 is in Barmer district of Rajasthan State. The area falls in the extreme hot and arid region of very low rainfall zone (<100mm) of the country. DNP was gazetted in the year 1980.

　　Across the landscape of Jaisalmer, altitudes are low, ranging from 210-300m (320m) above mean sea level (Govt. of India, 1994). Kar (1989) classified the landforms in Jaisalmer into eleven terrain categories; the predominant forms being sand dunes (44.8% of the area), and flat buried pediments/pavements/structural plains (28.4%). More ecologically relevant is the classification of natural desert habitats into sandy, gravelly, and rocky (Prakash 1962).

　　Sandy areas dominate the western parts of Jaisalmer district, while gravelly and rocky areas are scattered throughout central, southern and eastern areas. The DNP is barren with several sand dunes and a few hills in the north-western region. The Park forms a vast sandy and undulating terrain. From Khuri to Sam, the topography is gravel, rocky with a few isolated ridges (Kalra et al. 2006). Interdune (caused by wind) and sandy plains are other topographic features (Kalra et al. 2006).

　　The vegetation of major part of the arid region of the Thar falls under thorn forest type (Champion and Seth 1968). Khejri Prosopis cineraria is commonly found, which is revered and protected by the local communities specially the 'Bishnois'. The vegetation of DNP is quite sparse with open grassland, throny bushes, plantation and dunes as the broad habitat types. One-sixty eight plant species belonging to 48 families have been reported from this area (Pandey et al. 1985). Tree species viz. Commiphora wightii,, Ammannie desertorum, Acacia spp., Dipcadi erythraem, Enneatogon, Ephedra foliata, Glossonema varians, Helitropium rariflorum, Limeum indicum, Tecomella undulata brachystachyus Moringa concanensis, Rhynchosia schimpari, Seddera latifolia, Sesuvium sesuvioides, Tephrosia falciformis, Tribulus rajasthanensis and Ziziphus truncate provide sustenance to the desert fauna.

　　The biota of Thar has both mesic and desert elements owing to location of the Thar in the Saharo-Tharian Basin. 69% of herpetofauna and 54% of mammalian fauna represent the Sahraian affiliation. Sixty species of mammals, 8 species of amphibians, 51 species of reptile are known from the Thar (Baqri and Kankane 2001). The endemic reptile species of the Thar Desert are Laungwala Toad-headed Agama Bufoniceps laungwalansis , Sindh Awl-headed Snake Lytorhynchus paradoxus are also found in DNP. Many more endemic and endangered mammal, bird and reptile species are found in DNP. Fourteen species of lizards and 7 species of snakes have been recorded from this area (Agarwal 2007). Records of important reptile species such as 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 have been established based on recent studies. More than 100 bird species have been listed from DNP including a good population of the Great Indian Bustard (locally called Godawan) (Kalra et al. 2006) and is a home for migrant Houbara Bustard. The important mammal species of the area includes Chinkara Gazella bennetti, Desert Fox Vulpes vulpes, Indian Fox Vulpes bengalensis, Desert Cat Felis silvestris, Hairy-footed Gerbil Gerbillus gleadowi, Desert hare Lepus nigrricollis dayanus and Long-eared hedgehog Hemeichinus auritus.

　　The Thar desert is the most thickly populated desert in the world with an average density of 83 persons/km2 (compared to 7km2 of other deserts) (Baqri and Kankane 2001). However, the human population within the DNP is low (4-5 persons per km2). There are 73 villages and also settlements or Dhanis existing within the Park. These communities have inhabited this area for hundreds of years and with their rich culture and tradition they are an integral part of this ecosystem.