Odisha Semi-Evergreen Rain Forests

The Odisha Semi-Evergreen Rain Forests are a belt of tropical moist broadleaf forests along the coastal plain of Odisha. They lie between the Eastern Highlands Moist Deciduous Forests to the west and the Bay of Bengal to the east, and are fed by the monsoon downpours sweeping in from the ocean. Given below is a description of the ecoregion by the World Wildlife Fund for Nature (WWF):

The Odisha Semi-Evergreen Rain Forests are neither exceptionally species-rich nor high in endemism. But this ecoregion does harbor several of the Indian Subcontinent bioregion’s charismatic large vertebrates. Some of these include the Tiger (Panthera tigris), which is the region’s largest predator, and the Asian Elephant (Elephas maximus), large herds of Gaur (Bos gaurus), and one of the most dangerous mammals in the region, the Sloth Bear (Melursus ursinus). The ecoregion’s position on the low hills in the northeastern Indian state of Orissa makes it vulnerable to the full force of the southwestern monsoon winds that sweep in from the Bay of Bengal. The rainfall from this monsoon and the ameliorating year-round oceanic influences create moister climatic conditions here than in the rest of the Deccan Peninsula. Therefore, the ecoregion represents the original extent of distinctly moister semi-evergreen forests that once existed to the east of the Eastern Ghats Mountains. The ecoregion has an ancient geological lineage of Gondwanaland origins. Therefore, it still harbors relicts of an ancient biota.

Within the predominant semi-evergreen forests of this ecoregion are patches of several other habitat types, such as canebrakes, wet bamboo brakes, moist bamboo brakes, lateritic semi-evergreen forests, and secondary moist bamboo breaks. But most of these habitat types may not be identifiable in the field because of excessive deforestation and changes in land-use practices. Gaussen et al. (1973) report the following five series of natural vegetation from this ecoregion: ShoreaBuchananiaCleistanthus, ShoreaCleistanthusCroton, ShoreaTerminaliaAdina, ShoreaSyzygium operculatumToona, and ShoreaDilleniaPterospermum. The typical floral community of these forests includes Artocarpus lakoocha, Michelia champaca, Celtis tetrandra, Bridelia tomentosa, B. verrucosa, Dillenia pentagyna, Saraca indica, Ficus spp., Mangifera indica, and Firmiana colorata in the upper story. The second story is characterized by Aphanamixis polystachya, Mesua ferrea, Phoebe lanceolata, Polyalthia spp., Macaranga peltata, Glochidion spp., and Litsea nitida. An understory of evergreen shrubs, canes, and herbs is also present. In the hilly areas with lateritic soils (the residual product of rock decay), the vegetation is characterized by Xylia xylocarpa, Pterocarpus marsupium, Anogeissus latifolia, Grewia tiliaefolia, Terminalia tomentosa, and Terminalia bellirica.

The ecoregion harbors fifty-nine mammal species. Although none are endemic to the ecoregion, several threatened species warrant conservation attention: the Tiger, Asian Elephant, Gaur, Wild Dog (Cuon alpinus), Sloth Bear, and Chousingha (Tetracerus quadricornis). The forests of this ecoregion-especially along the higher elevations-may provide dispersal habitat for tigers and leopards from Simlipal in the north to Andhra Pradesh in the south. Bird richness is higher, with more than 215 species, although none are endemic to the ecoregion. The ecoregion harbors a globally threatened species, the Lesser Florican (Eupodotis indica). Other birds that warrant conservation attention include the Oriental Darter (Anhinga melanogaster), Greater Flamingo (Phoenicopterus ruber), and White-Bellied Sea Eagle (Haliaeetus leucogaster).

More than 95 percent of this ecoregion’s habitat has been cleared. The remaining forest consists of scattered fragments of Xylia xylocarpa, Pterocarpus marsupium, Anogeissus latifolia, Grewia tiliaefolia, Terminalia tomentosa, and Terminalia bellirica. Even thirty years ago, Champion and Seth (1968) alluded to the sub-climax forests throughout most of the ecoregion when they said that “the undisturbed climatic climax no longer exists and we can only surmise that the rapid invasion of the damp deciduous forests and coastal sal by evergreen species after successful fire protection will lead to a climax included as tropical fully evergreen forests.” There are three protected areas that cover 1,102 sq km of the ecoregion, but with the exception of the proposed 970 sq km Chilka Reserve, the other protected areas are small, at less than 100 sq km.

Protected Areas That Overlap with the Ecoregion

  • Nandankanan
  • Chilka
  • Balukhand Konark

Cultivation, settlements, and grazing pressure from domestic livestock are the primary threats to the small areas of remaining habitat in the ecoregion. In an earlier analysis of biogeography and conservation gaps of India, Rodgers and Panwar (1988) divided the Gangetic plains into the upper and lower Gangetic plains biotic provinces. In a subsequent regional revision of conservation units, MacKinnon (1997) included most of Bangladesh in the lower Gangetic plain biounit. However, MacKinnon also included the patch of coastal semi-evergreen rain forest along the eastern side of the Eastern Ghats with the moist deciduous forests along the Gangetic plains. This ecoregion lies within Udvardy’s Mahanadian biogeographic province.

Image Attribution: The image above, sourced from Wikimedia Commons, shows a White-Bellied Sea Eagle (Haliaeetus leucogaster). A majestic bird that is found from South Asia to Australia, the eagle is associated with the Odisha Semi-Evergreen Rain Forests ecoregion, where it is found along wetlands and river courses. The photograph was uploaded by Manoj Iritty.