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Chhota-Nagpur dry deciduous forests (IM0203)

 

Chhota-Nagpur dry deciduous forests
Dalma Wildlife Sanctuary, India
Photograph by Doug Helmer


 

Where
Southern Asia: Eastern India
Biome
Tropical and Subtropical Dry Broadleaf Forests

  Size
47,300 square miles (122,400 square kilometers) -- about the size of New York
Critical/Endangered
 
 

· Location and General Description
· Biodiversity Features
· Current Status
· Threats
· Ecoregion Justification
· References
More Photos

The Chhota-Nagpur Dry Deciduous Forests [IM0203] still harbor large populations of Asia's largest predator and largest herbivore, the tiger (Panthera tigris) and the Asian elephant (Elephas maximus), respectively. Both are still able to roam and live within the large habitat blocks of this ecoregion, a rare phenomenon in this bioregion. The Chhota-Nagpur Plateau also has a flora and fauna that are distinct from the adjacent areas (Rodgers and Panwar 1988), with several pockets of endemic plants. In the geological past, this plateau formed a link between Satpura Hill Ranges and eastern Himalaya that allowed species exchanges between these ranges (Hora 1949).

Location and General Description

The ecoregion represents the dry deciduous forests on the Chhota-Nagpur Plateau and lies between the moist deciduous forests of the Eastern Ghats and Satpura Range and of the lower reaches of the Gangetic Plains. It extends across the eastern Indian states of Bihar, Madhya Pradesh, and West Bengal.

The Gondwana substrates attest to the plateau's ancient origin. It is part of the Deccan Plate, which broke free from the southern continent during the Cretaceous to embark on a 50-million-year journey that was violently interrupted by the northern Eurasian continent. The northeastern part of the Deccan Plateau, where this ecoregion sits, was the first area of contact with Eurasia.

The plateau receives less rainfall than the adjacent ecoregions that support moist deciduous forests. Therefore, the vegetation is drier than in the adjacent ecoregions. The dry deciduous forests typically are composed of three stories, with an upper canopy reaching 15-25 m, a high understory at 10-15 m, and an undergrowth at about 3-5 m. The vegetation is characterized by Shorea robusta, usually in association with Anogeissus latifolia, Terminalia alata, Lagerstroemia parviflora, Pterocarpus marsupium, Aegle marmelos, Syzygium operculatum, Symplocus racemosa, and Croton oblongifolius (Puri et al. 1989; Davis et al. 1995). Lianas are common in denser forests.

A dry deciduous scrub that grows to about 3-6 m in height is a common habitat type in this ecoregion. This scrub includes bamboo and shrubs such as Holarrhena and Dodonaea (Puri et al. 1989). At higher altitudes, there are shola-type forests characterized by Phoenix robusta, Pterospermum acerifolium, and Clematis nutans (WWF and IUCN 1995). The ecoregion also includes patches of moist deciduous forests and swampy areas, with several interesting plant species (Syzygium cumini, Manilkara hexandra, Ficus spp., Mallotus philippinensus) that are typical of moist deciduous forests.

Biodiversity Features

Although Aglaia haselettiana, Carum villosum, and Pycnocyclea glauca are endemic, endangered plant species in this ecoregion, Diospyros melanoxylon, Madhuca longifolia, Butea monosperma, and Shleichera oleosa, are more economically useful species.

The ecoregion's fauna is neither exceptionally species-rich nor distinctive. The ecoregion's mammal fauna includes seventy-seven species, but none are endemic to it. Nevertheless, several of India's large charismatic vertebrates, including several that are threatened such as the tiger, Asian elephant, wild dog (Cuon alpinus), sloth bear (Melursus ursinus), chousingha (Tetracerus quadricornis), blackbuck (Antilope cervicapra), and chinkara (Gazella bennettii) (IUCN 2000), are found here. Importantly, unlike in many other ecoregions in this bioregion, there still are large areas of habitat capable of supporting viable populations of these species. These habitat blocks are included in two Level I TCUs (Dinerstein et al. 1997) that extend into the ecoregion.

There are almost 280 bird species, but none are endemic to the ecoregion. However, it harbors several species that are of conservation importance, including the globally threatened lesser florican (Eupodotis indica). Some of the hornbills, notably the Indian grey hornbill (Ocyceros birostris) and Oriental pied-hornbill (Anthracoceros albirostris), which need mature trees for nesting, should be focal species for conservation management.

Current Status

More than half of the natural forests in this ecoregion have been cleared; however, extensive areas of intact forest remain in the northern areas. The thirteen protected areas in the ecoregion cover more than 6,700 km2, representing about 6 percent of the ecoregion (table 1). The average size of a protected area exceeds 500 km2, and two-Sanjay and Palamau-are larger than 1,000 km2. These large protected areas provide the essential core areas for the large vertebrates in this ecoregion. However, these reserves must be included in larger conservation landscapes for more effective long-term conservation of these species (Wikramanayake et al. 1999).

Table 1. WCMC (1997) Protected Areas That Overlap with the Ecoregion.

Protected Area

Area (km2)

IUCN Category

Sanjay [IM0207]

1,020

II

Lawalang

410

IV

Koderma

180

IV

Hazaribagh

450

IV

Palamau

1,330

II

Topchanchi

40

IV

Ramnabagan

150

IV

Dalma

630

IV

North Simlipal

420

II

Bhimbandh

910

IV

Gautam Budha [IM0120]

110

IV

Tamor Pingla

600

IV

Semarsot

470

IV

Total

6,720

 
Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.

Types and Severity of Threats

Like many of the other ecoregions in this bioregion, livestock grazing has greatly affected the vegetation (Puri et al. 1989). However, extensive areas that are being mined for iron ore and open-pit coal mines pose very significant threats to the habitat, especially to critical migration paths of elephants and dispersal routes for tigers.

Justification of Ecoregion Delineation

In a previous analysis of conservation units, Rodgers and Panwar (1988), and subsequently MacKinnon (1997), divided the Deccan Peninsula into five biotic provinces and sub-biounits, respectively. But each of these units contains several vegetation types that extend over large areas. In this analysis, we represent these large ecosystems in separate ecoregions (in keeping with our definition of an ecoregion as an ecosystem of regional extent). Therefore, we modified the boundaries of Rodgers and Panwar's biotic province 6D (which is the same as MacKinnon's sub-biounit 16b) to include only the large expanse of dry deciduous forest in the Chhota-Nagpur Dry Deciduous Forests [IM0203]. We used MacKinnon's (1997) digital map of the original vegetation to define the boundaries of this ecoregion.

References

References for this ecoregion are currently consolidated in one document for the entire Indo-Pacific realm.
Indo-Pacific Reference List

Prepared by: Gopal S. Rawat and Eric D. Wikramanayake
Reviewed by:

This text was originally published in the book Terrestrial ecoregions of the Indo-Pacific: a conservation assessment from Island Press. This assessment offers an in-depth analysis of the biodiversity and conservation status of the Indo-Pacific's ecoregions.

For more general information on this ecoregion, go to the WildWorld version of this description.

All text by World Wildlife Fund © 2001