The Northwestern thorn scrub forests ecoregion represents a large expanse of degraded dry forest surrounding the Thar Desert. Neither exceptionally species-rich nor high in endemism, the ecoregion nevertheless harbors viable populations of Indian Gazelle (Gazella bennettii), Chousingha (Tetracerus quadricornis), and Blackbuck (Antilope cervicapra)
Location and General Description
WWF
The ecoregion represents the thorn scrub forests in northwestern region of the Indian subcontinent. Many ecologists consider this thorn scrub to represent a degraded state of tropical dry forests. The ecoregion stretches across the border between India and Pakistan and covers parts of Gujarat, Rajasthan, Haryana, and Punjab states of India and the lower parts of Jammu and Kashmir. The average annual rainfall in this arid ecoregion is less than 750 millimeters (mm). The temperature can exceed 45 degrees Celsius during the hottest months, and in winter [[temperature]s] can drop to below freezing.
The flat alluvial lowlands extend into the low hills. Local variations in soil salinity affect the distribution of vegetation; patches of highly saline soil usually are bare of vegetation. The vegetation is stunted and open, dominated by Acacia species such as A. senegal and A. leucophloea that rarely exceed six meters (m) in height. Other characteristic species (Biodiversity) that make up the vegetation are Prosopis spicigera, Capparis zeylanica, Salvadora spp., Carissa spp., Gymnosporia spp., Grewia spp., and Gardenia spp. and xerophytic climbers such as species of Tragia, Rivea, Tinospora, Vitis, and Peristrophe. In drier areas, the thorn forest transitions into xerophytic shrubland and semiarid vegetation, usually dominated by Euphorbia species. Intermingled with the Euphorbia scrub is a Zizyphus scrub that is characterized by Zizyphus nummularia with Acacia leucocephala, Acacia senegal, Anogeissus pendula, and Dicrostachys cinerea. The poor soils along rocky tracts promote a Cassia-Butea community. Closer to the coast, where the soils are more saline, the community includes Salvadora and Tamarix. The southwestern part of the Aravalli Range supports a distinct deciduous forest characterized by Anogeissus pendula, Aegle marmelos, Boswellia serreta, Cassia fistula, Mitragyna parviflora, Diospyros melanxylon, and Wrightia tinctoria.
Biodiversity Features
The ecoregion is not exceptionally rich or high in endemism but does harbor several large mammals of conservation importance, including the leopard (Panthera pardus), caracal (Felis caracal), chinkara (Gazella bennettii), chousingha (Tetracerus quadricornis), and blackbuck (Antilope cervicapra). Overall, the mammal fauna consists of about ninety species, including two bats that are endemic to the ecoregion (Table 1).
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Table 1. Endemic and Near-Endemic Mammal Species. Family Species Rhinolophidae Triaenops persicus* Rhinopomatidae Rhinopoma muscatellum* An asterisk signifies that the species' range is limited to this ecoregion. Both of these bats are strict endemics, their known range being limited to this ecoregion. The chousingha and blackbuck are threatened species and should be focal species for conservation actions. The Aravalli Hill Ranges and the surrounding flat areas support two very distinct rodent communities that are influenced by the geology, soil (Northwestern thorn scrub forests) , and vegetation conditions. Detailed studies are under way to determine the species composition of these communities.
The bird fauna consists of an impressive list of more than 400 species (Biodiversity), among the highest for ecoregions in this bioregion. The list includes two endemic species (Table 2).
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Table 2. Endemic and Near-Endemic Bird Species. Family Common Name Species Paridae White-winged tit Parus nuchalis Sylviidae Rufous-vented prinia Prinia burnesii* An asterisk signifies that the species' range is limited to this ecoregion. The rufous-vented prinia is a strict endemic limited to this ecoregion (Northwestern thorn scrub forests) , and the white-winged tit is a near endemic shared with the adjacent Khathiarbar-Gir Dry Deciduous Forests. The ecoregion also harbors the globally threatened Indian bustard (Ardeotis nigriceps) and lesser florican (Eupodotis indica).
Current Status
More than 90 percent of this ecoregion's natural habitat has been converted, and only small, scattered fragments remain. There are an astounding sixty protected areas in the ecoregion (Table 3), but they cover only about 11,000 square kilometers (km2), or just over 2 percent of the ecoregion area. Many of the protected areas are small, at an average size of just over 175 km2.
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Table 3. WCMC (1997) Protected Areas That Overlap with the Ecoregion. Protected Area Area (km2) IUCN Category Dhrun 310 II Kachau 220 IV Khurkhera 180 IV Kirthar 2,980 II Mahal Kohistan 650 IV Hab Dam 460 IV Kinjhar Lake 180 IV Hadero Lake 10 IV Haleji Lake 20 IV Bijoro Chach 1 IV Norange 2 IV Deh Jangisar 3 UA Keb Bunder North 90 IV Pai 20 UA Lakhi 1 IV Goleen Gol 10 UA Deh Sahib Saman 3 UA Khipro 40 UA Narayan Sarovar 830 IV Barda 210 IV Velavadar 50 II Nal Sarovar 50 IV Jessore 260 IV Doli Closed Area 700 VII Indus River #1 1,370 UA Dhoung Block 20 IV Dosu Forest 20 UA Drigh Lake 1 IV Mando Dero 140 UA Resi 50 UA Sheikh Buddin 240 IV Kalabagh Game Reserve 10 Thanadarwala 40 UA Nemal Lake 4 IV Chashma Lake 220 IV Taunsa Barrage 70 IV Kot Zabzai 100 UA Sodhi 50 IV Daphar 30 IV Head Qadirabad 30 UA Bhon Fazil 30 UA Gat Wala 60 UA Bhono 20 UA Kharar Lake 2 IV Kamalia Plantation 40 UA Chichawatni Plantation 50 UA Abohar 190 IV Indo-Pak Border 30 UA Chaupalia 100 UA Head Islam/Chak Kotora 30 UA Daulana 20 UA Bahwaalpur Plantation 5 UA Harike Lake 1 IV Bir Motibagh 30 IV Bir Bunerheri 10 IV Chautala 110 IV Bir Gundial Pura 30 IV Simbalbara 160 IV Sultanpur 20 IV Renuka 40 IV Total 10,653 Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets. The local people, especially the Bishnoi communities, have a cultural reverence for wild animals, particularly blackbuck and the tree Prosopis cinerea. For this reason, the wildlife and habitat (Northwestern thorn scrub forests) have been protected over the years.
Types and Severity of Threats
 Blackbuck (Antilope cervicapra), Pakistan. (Photograph by WWF / Mauri Rautkari This ecoregion is subject to intensive degradation threats from livestock grazing. Associated human impacts such as lopping and cutting of vegetation for fuelwood, setting fires to create grazing lands, and settlements also contribute to habitat degradation (Habitat fragmentation). The marble beds of the ancient Aravalli Range are being heavily mined. Rodgers and Panwar present an analysis of conservation gaps and needs for the Indian part of the ecoregion.
Justification of Ecoregion Delineation
 Pushkar, Rajastan, India. (Photograph by Boschidar Ganev) In a previous analysis of conservation units, MacKinnon placed these desert and thorn scrub forests of northwestern India and Pakistan in Biounit (13) along with other habitat types that included dry deciduous forests and deserts. In keeping with our rules for representing distinct habitat types of [[region]al] extent in separate ecoregions, we used MacKinnon's digital map of the original vegetation to delineate and separate the thorn scrub forests from the desert and dry deciduous forests. The thorn scrub around the Thar Desert therefore was placed in the Northwestern Thorn Scrub Forests. The Northwestern Thorn Scrub Forests lie in both the Indus-Ganges monsoon forest and Thar Desert biogeographic provinces.
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