East Deccan dry-evergreen forests
Published: August 25, 2008, 5:04 am
Updated: August 25, 2008, 5:04 am
This article has been reviewed by the following Topic Editor:
Mark McGinley Introduction
Satellite View of the Southeast coast of India (Source: USGS)
The vegetation in the East Deccan Dry Evergreen Forests has an unusual physiognomy that makes it distinctive from most of the other dry forests. Unlike other dry forests of the Indo-Pacific region that lose their leaves for part of the year (i.e., during the nonmonsoonal season), these forests stay green during the long dry season.
Location and General Description
The ecoregion extends as a narrow strip along the southern coastal areas of Andhra Pradesh and Tamil Nadu states in India, where it represents the narrow strip of dry evergreen forest formation.
Geologically, this ecoregion has Gondwanaland origins. The average rainfall is 800 millimeters (mm). Most of the precipitation occurs during the brief northeast monsoon between October and December. Maximum temperatures during the long dry season can reach a stifling 44° Celsius (°C).
The original vegetation had emergent species of deciduous elements, such as Albizzia amara and Chloroxylon spp. But the original canopy-forming deciduous species have succumbed to human pressures, and the shrubby evergreen species now form a closed evergreen understory. Therefore, the existing vegetation type represents a low forest (up to 10 meters [m]) with a complete, closed canopy consisting of mostly small leathery-leaved evergreen trees with short trunks and spreading crowns. A large number of climbers are present, but bamboos are completely absent.
The characteristic floristic elements are Manilkara hexandra, Mimusops elengi, Diospyros ebernum, Strychnos nux-vomica, Eugenia spp., Drypetes sepiaria, and Flacourtia indica. The degraded stages of this forest have been categorized as tropical dry evergreen scrub by Puri et al. and are typically dominated by thorny species such as Zyzyphus glabarrima, Dicrostachys cinerea, Randia dumetorum, and Carissa spinarum.
Biodiversity Features
The ecoregion does not contain any endemic mammals or birds. But the sixty-six known mammal species include two threatened species: the wild dog (Cuon alpinus) and sloth bear (Melursus ursinus). Other species that deserve conservation attention in this ecoregion include its largest predator, the common leopard (Panthera pardus), and some of the smaller predators such as the jungle cat (Felis chaus) and leopard cat (Prionailurus bengalensis). The mammal community includes several ungulates of conservation importance such as the blackbuck (Antilope cervicapra), the chinkara (Gazella bennettii), and the small Indian chevrotain or mouse deer (Moschiola meminna). The Sriviliputhur (Kamarajar District in Tamil Nadu) and Amaravathy Nagar (Coimbatore District) have the largest remaining populations of the threatened grizzled giant squirrel (Ratufa macroura).
Bird richness is greater, with 230 species. The Jerdon's courser (Rhinoptilus bitorquatus) is endangered, and the spot-billed pelican (Pelecanus philippensis) and lesser florican (Eupodotis indica) are globally threatened. Some other birds that deserve conservation attention as focal species because of their need for relatively intact habitat and low tolerances of disturbance include the woolly-necked stork (Ciconia episcopus), white-bellied sea-eagle (Haliaeetus leucogaster), and Indian grey hornbill (Ocyceros birostris).
Current Status
| Table 1. WCMC (1997) Protected Areas That Overlap with the Ecoregion. |
| Protected Area | Area (km2) | IUCN Category |
| Vettangudi | 30 | IV |
| Nelapattu | 130 | IV |
| Total | 160 | |
| Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets. |
Hundreds of years of human impact have taken a heavy toll on the natural habitat of this ecoregion, and more than 95 percent of the ecoregion is deforested. The remaining forests are scattered small fragments. The two small, protected areas cover less than 200 square kilometers (km2) (Table 1), which is less than 1 percent of the ecoregion's area. Marakanam, a sacred grove near Pondicherry, is fairly well protected and represents an important example of this vegetation type.
Types and Severity of Threats
Like most of the other ecoregions in the Indian Subcontinent, this ecoregion is also subjected to heavy deforestation and grazing pressure from domestic livestock. The stunted scrub vegetation present throughout most of the ecoregion is indicative of long years of grazing practices. The remnant sal (Shorea robusta) forests are being rapidly lost to podu, or shifting cultivation.
Invasion by Prosopsis, a thorny exotic plant that is unpalatable to domestic livestock, is being used extensively in reforestation programs and will certainly usurp the preferred habitat of the Jerdon's courser.
Poaching is rampant in areas with Naxalite conflicts, especially in the Satmala Hills, Pakla Wildlife Sanctuary, and Etunagaram. The ground situation makes patrolling by the forest department staff nearly impossible.
Justification of Ecoregion Delineation
During previous analyses of conservation units, Rodgers and Panwar and MacKinnon divided the largest biogeographic unit in India, the Deccan Peninsula, into five subunits or biotic provinces. Each of these units contained several distinct habitat types. In keeping with our rules for defining ecoregions as conservation units that represent distinct habitat types, we identified the distinct dry evergreen forests along the southeastern coast of the Deccan Peninsula as the East Deccan Dry Evergreen Forests.
Additional Information on this Ecoregion
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Citation
World Wildlife Fund (Lead Author);Mark McGinley (Topic Editor) "East Deccan dry-evergreen forests". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth August 25, 2008; Last revised Date August 25, 2008; Retrieved May 24, 2013 <http://www.eoearth.org/article/East_Deccan_dry-evergreen_forests>
The Author
Known worldwide by its panda logo, World Wildlife Fund (WWF) leads international efforts to protect endangered species and their habitats. Now in its fifth decade, WWF works in more than 100 countries around the globe to conserve the diversity of life on Earth. With nearly 1.2 million members in the U.S. and another 4 million worldwide, WWF is the world's largest privately financed conservation organization. WWF directs its conservation efforts toward three global goals: 1) saving endangered ... (Full Bio)
Introduction
Satellite View of the Southeast coast of India (Source: USGS)
The vegetation in the East Deccan Dry Evergreen Forests has an unusual physiognomy that makes it distinctive from most of the other dry forests. Unlike other dry forests of the Indo-Pacific region that lose their leaves for part of the year (i.e., during the nonmonsoonal season), these forests stay green during the long dry season.
Location and General Description
The ecoregion extends as a narrow strip along the southern coastal areas of Andhra Pradesh and Tamil Nadu states in India, where it represents the narrow strip of dry evergreen forest formation.
Geologically, this ecoregion has Gondwanaland origins. The average rainfall is 800 millimeters (mm). Most of the precipitation occurs during the brief northeast monsoon between October and December. Maximum temperatures during the long dry season can reach a stifling 44° Celsius (°C).
The original vegetation had emergent species of deciduous elements, such as Albizzia amara and Chloroxylon spp. But the original canopy-forming deciduous species have succumbed to human pressures, and the shrubby evergreen species now form a closed evergreen understory. Therefore, the existing vegetation type represents a low forest (up to 10 meters [m]) with a complete, closed canopy consisting of mostly small leathery-leaved evergreen trees with short trunks and spreading crowns. A large number of climbers are present, but bamboos are completely absent.
The characteristic floristic elements are Manilkara hexandra, Mimusops elengi, Diospyros ebernum, Strychnos nux-vomica, Eugenia spp., Drypetes sepiaria, and Flacourtia indica. The degraded stages of this forest have been categorized as tropical dry evergreen scrub by Puri et al. and are typically dominated by thorny species such as Zyzyphus glabarrima, Dicrostachys cinerea, Randia dumetorum, and Carissa spinarum.
Biodiversity Features
The ecoregion does not contain any endemic mammals or birds. But the sixty-six known mammal species include two threatened species: the wild dog (Cuon alpinus) and sloth bear (Melursus ursinus). Other species that deserve conservation attention in this ecoregion include its largest predator, the common leopard (Panthera pardus), and some of the smaller predators such as the jungle cat (Felis chaus) and leopard cat (Prionailurus bengalensis). The mammal community includes several ungulates of conservation importance such as the blackbuck (Antilope cervicapra), the chinkara (Gazella bennettii), and the small Indian chevrotain or mouse deer (Moschiola meminna). The Sriviliputhur (Kamarajar District in Tamil Nadu) and Amaravathy Nagar (Coimbatore District) have the largest remaining populations of the threatened grizzled giant squirrel (Ratufa macroura).
Bird richness is greater, with 230 species. The Jerdon's courser (Rhinoptilus bitorquatus) is endangered, and the spot-billed pelican (Pelecanus philippensis) and lesser florican (Eupodotis indica) are globally threatened. Some other birds that deserve conservation attention as focal species because of their need for relatively intact habitat and low tolerances of disturbance include the woolly-necked stork (Ciconia episcopus), white-bellied sea-eagle (Haliaeetus leucogaster), and Indian grey hornbill (Ocyceros birostris).
Current Status
| Table 1. WCMC (1997) Protected Areas That Overlap with the Ecoregion. |
| Protected Area | Area (km2) | IUCN Category |
| Vettangudi | 30 | IV |
| Nelapattu | 130 | IV |
| Total | 160 | |
| Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets. |
Hundreds of years of human impact have taken a heavy toll on the natural habitat of this ecoregion, and more than 95 percent of the ecoregion is deforested. The remaining forests are scattered small fragments. The two small, protected areas cover less than 200 square kilometers (km2) (Table 1), which is less than 1 percent of the ecoregion's area. Marakanam, a sacred grove near Pondicherry, is fairly well protected and represents an important example of this vegetation type.
Types and Severity of Threats
Like most of the other ecoregions in the Indian Subcontinent, this ecoregion is also subjected to heavy deforestation and grazing pressure from domestic livestock. The stunted scrub vegetation present throughout most of the ecoregion is indicative of long years of grazing practices. The remnant sal (Shorea robusta) forests are being rapidly lost to podu, or shifting cultivation.
Invasion by Prosopsis, a thorny exotic plant that is unpalatable to domestic livestock, is being used extensively in reforestation programs and will certainly usurp the preferred habitat of the Jerdon's courser.
Poaching is rampant in areas with Naxalite conflicts, especially in the Satmala Hills, Pakla Wildlife Sanctuary, and Etunagaram. The ground situation makes patrolling by the forest department staff nearly impossible.
Justification of Ecoregion Delineation
During previous analyses of conservation units, Rodgers and Panwar and MacKinnon divided the largest biogeographic unit in India, the Deccan Peninsula, into five subunits or biotic provinces. Each of these units contained several distinct habitat types. In keeping with our rules for defining ecoregions as conservation units that represent distinct habitat types, we identified the distinct dry evergreen forests along the southeastern coast of the Deccan Peninsula as the East Deccan Dry Evergreen Forests.
Additional Information on this Ecoregion
|
Disclaimer:
This article is taken wholly from, or contains information that was originally published by, the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.
|
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