Northwestern thorn scrub forests

The Northwestern thorn scrub forests, presently known as Aravalli west thorn scrub forests,[2] is a xeric shrubland ecoregion of Pakistan and Northern India, stretching along the border lowlands and hills between the two countries. Once covered in deciduous forest, this ecoregion has been degraded through agriculture and the extraction of timber so that it currently has a scanty covering of thorny scrub dominated by such trees as Acacia senegal, Acacia leucophloea and Prosopis cineraria. Where the soils are particularly saline, there are patches of semi-desert. A number of mammals are found in this habitat, including about four hundred species of bird. Some small areas are protected but the collection of firewood and the conversion of the land to subsistence farming continues.

Northwestern thorn scrub forests
Crop fields in Sialkot, Punjab, Pakistan
Map of the Northwestern thorn scrub forests ecoregion
Ecology
RealmIndomalayan
Biomedeserts and xeric shrublands
Borders
List
Geography
Area486,906 km2 (187,995 sq mi)
Countries
states of India & provinces of Pakistan
List
Conservation
Conservation statuscritical/endangered
Protected20,150 km² (4%)[1]

Location and description

The ecoregion encircles the Thar Desert and Indus Valley Desert ecoregions. It stretches along the border lowlands and hills between India and Pakistan and includes: the western half of Gujarat (excluding the mountain of Girnar), and extending through Rajasthan, where it is bounded on the southeast by the Aravalli Range; most of Haryana and Punjab states of India as well as the Jammu region of Jammu and Kashmir, extending to the foothills of the Himalayas; in Pakistan, most of Punjab province, extending into easternmost Northwest Frontier and Baluchistan provinces and western Sindh.

This ecoregion, together with the Thar Desert and Indus Valley Desert ecoregions, form Miklos Udvardy's "Thar Desert" Biogeographic province.[3]

Climate

The climate of the ecoregion consists of Hot semi-arid (Köppen climate classification (BSh)) and Arid (Köppen climate classification (BWh)) climates. This climate is characteristic of steppes, grasslands, and forests. The temperature includes, hot summers and cool or dry winters. Precipitation averages 500–600 mm/year with heavy rainfalls and evening thunderstorms with the possibility of cloudbursts and flash floods in the monsoon season, late July–August. This being said, it only receives enough rainfall to support scrub. It does not receive enough rainfall to feature in the humid subtropical climate.

Flora

The Northwestern thorn scrub forests are thought to be tropical dry forests that have been degraded through intensive agriculture and grazing into stunted and open thorn scrub, dominated by trees such as Acacia senegal and Acacia leucophloea, as well as Prosopis cineraria, Capparis zeylanica, and species of Salvadora, Gymnosporia, Grewia, and Gardenia. However the region also contains patches of semi-desert where the soil is particularly saline.[4][5]

Fauna

Despite the large scale forest clearance large mammals still remain in the ecoregion including leopard and their prey such as chinkara (Gazella bennettii) and the threatened species chousingha (Tetracerus quadricornis), and blackbuck (Antilope cervicapra). The scrubland is also home to another large cat, the caracal, which preys on mice, birds, and reptiles. There are two endemic mammals, both bats: Triaenops persicus and the small mouse-tailed bat (Rhinopoma muscatellum).

There are more than 400 species of birds in the region including the endemic rufous-vented grass babbler (Laticilla burnesii), the near-endemic white-winged tit (Parus nuchalis) and the threatened great Indian bustard (Ardeotis nigriceps) and lesser florican (Eupodotis indica).

Threats and preservation

Over 90% of the ecoregion has been converted to human use, and the remaining habitat is highly fragmented. There are many protected areas but they are very small and unconnected and even these are liable to invasion for firewood collecting and clearance for planting. However the traditions of the Bishnoi community based in this region extend protection to some wildlife, especially the blackbuck and the tree.

See also

References
  1. Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545; Supplemental material 2 table S1b.
  2. Dinerstein, Eric; Olson, David; Joshi, Anup; Vynne, Carly; Burgess, Neil D.; Wikramanayake, Eric; Hahn, Nathan; Palminteri, Suzanne; Hedao, Prashant; Noss, Reed; Hansen, Matt (June 2017). "An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm". BioScience. 67 (6): 534–545. doi:10.1093/biosci/bix014. ISSN 0006-3568. PMC 5451287. PMID 28608869.
  3. "Northwestern thorn scrub forests". Terrestrial Ecoregions. World Wildlife Fund.
  4. Champion, H. G., and S. K. Seth. 1968. A revised survey of the forest types of India. Government of India Press
  5. Puri, G.S., Gupta, R.K., and Meher-Homji, V.M.P.S. 1989. Forest Ecology Volume 2. New Delhi, India: Oxford & IBH Publishing Company
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