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 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(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 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 (Champion and Seth 1968).
The characteristic floristic elements are Manilkara hexandra, Mimusops elengi, Diospyros ebernum, Strychnos nux-vomica, Eugenia spp., Drypetes sepiaria, and Flacourtia indica (Champion and Seth 1968). The degraded stages of this forest have been categorized as tropical dry evergreen scrub by Puri et al. (1989) and are typically dominated by thorny species such as Zyzyphus glabarrima, Dicrostachys cinerea, Randia dumetorum, and Carissa spinarum.
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 (IUCN 2000). 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).
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 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.
Table 1. WCMC (1997) Protected Areas That Overlap with the Ecoregion.
Protected Area Area (km2) IUCN Category
Vettangudi [IM1301] 30 IV
Nelapattu 130 IV
Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.
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 (Rawat and Babu 1995).
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 (1988) and MacKinnon (1997) 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 [IM0204].
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, Ajay Desai, Hema Somanathan, and Eric D. Wikramanayake