Location and General Description
This ecoregion lies along one of Asia's largest rivers, the Ganges. Originating in the western Himalayas, the river flows east along most of the length of the long mountain range to eventually join with the Brahmaputra River and head south to the Bay of Bengal. This ecoregion extends through the upper reaches of the Ganges River, across the northern Indian states of Uttar Pradesh, Haryana, and Bihar.
The southwest monsoon originating in the Bay of Bengal provides the ecoregion's precipitation. Therefore, the eastern reaches receive more moisture, with a gradual trend towards drier conditions as one goes west. Annual rainfall averages less than 500 mm. Topographically, the ecoregion has little relief except for floodplain scarps and ravines carved out by gully erosion (Rodgers and Panwar 1988). The substrate consists of deep alluvial soils deposited over the eons by the Ganges River.
The original moist deciduous habitat probably was dominated by Shorea robusta that formed a top canopy reaching 25-35 m. Other associated species included Terminalia tomentosa, Terminalia belerica, Lagerstroemia parviflora, Adina cordifolia, Dillenia pentagyna, Stereospermum suaveolens, and Ficus spp. (Puri et al. 1989). Patches of mesophilous grasslands, or savanna ecosystems, with Saccharum spontaneum, Saccharum narenga, Saccharum benghalense, and Vetiveria zizanioides intersperse the forest lands (Puri et al. 1989), representing early seral stages maintained by fire, flood, and grazing by domestic livestock.
Several centuries ago, when the habitat was intact, this ecoregion harbored a rich wildlife community that included tiger, greater one-horned rhinoceros, Asian elephant, wild water buffalo, swamp deer, sloth bear (Melursus ursinus), and several hornbill species (Rodgers and Panwar 1988). Many of these space-dependent species are gone from much of the ecoregion, victims of the relentless wave of habitat destruction that has swept through most of the ecoregion.
The seventy-nine known mammal species do not include any ecoregional endemic species. But there are some threatened mammals, including the tiger, Asian elephant, sloth bear, chousingha (Tetracerus quadricornis), and possibly small refuge populations of swamp deer in some habitat patches. With the exception of a few forested landscapes along the Himalayan foothills, habitat fragmentation is too far advanced throughout much of the ecoregion to support viable populations of the larger predators and herbivores such as tigers and Asian elephants that used to be common here. Nevertheless, the intact habitat landscapes and the protected areas within these forest fragments have been included in a high-priority (Level I) TCU (Dinerstein et al. 1997) that extends into the adjacent ecoregions to the north.
The bird fauna consists of about 290 species. There are no ecoregional endemic species, although the Indian bustard (Ardeotis nigriceps) and lesser florican (Eupodotis indica) are globally threatened species. The Indian grey hornbill (Ocyceros birostris) and Oriental pied-hornbill (Anthracoceros albirostris) need mature habitat for nesting and can be used as focal species for conservation management.
The Ganges River supports a population of freshwater dolphins (Platanista gangetica), and the associated wetlands support a rich and diverse waterfowl community that includes many migrant bird species as well as the mugger crocodile (Crocodylus palustris) and Gangetic gharial (Gavialis gangeticus).
More than 95 percent of this vast ecoregion has been degraded or converted into agriculture and settlement areas by the dense human population that has settled here for thousands of years. Only one large block of habitat now remains, running along the Himalayan foothills in Uttar Pradesh and including Rajaji, Corbett, and Dudwa national parks.
The nine protected areas cover only 2,050 km2, amounting to less than 1 percent of the ecoregion area (table 1). Among these, Rajaji and Corbett are important tiger reserves. Whereas Rajaji is the largest reserve completely within the ecoregion, Corbett (1,300 km2) is a larger reserve that also extends into the adjacent ecoregion. None of the other reserves are more than 300 km2 in extent, and the average size of the protected areas represented within this ecoregion is only 227 km2.
Table 1. WCMC (1997) Protected Areas That Overlap with the Ecoregion.
Protected Area Area (km2) IUCN Category
Corbett [IM0301] 260 II
National Chambal [IM0206] 130 PRO
Rajaji 790 II
Hastinapur 20 IV
Karera Great Indian Bustard 200 IV
Ranipur 230 IV
Ken Gharial 80 IV
Kishanpur 70 IV
Sohagabarwa [IM0115] 270 IV
Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.
Nevertheless, the landscape that extends from Rajaji National Park to Corbett National Park is one of the most important conservation areas for tigers and elephants. This area is believed to have about 750 elephants and about 140 tigers (Singh 1986, in Johnsingh et al. 1990). With the inclusion of Corbett National Park and Sonanadi Wildlife Sanctuary in Rajaji National Park, this potential conservation landscape can be as large as 2,500 km2 (Johnsingh et al. 1990).
Types and Severity of Threats
Impacts from human activities have devastated the natural habitat in this river plain for many years and continue to threaten the small patches of remaining forests and the biodiversity within them. Rodgers and Panwar (1988), subsequently updated by Rodgers et al. (2000), have highlighted the conservation gaps in this region with specific proposals for additional protection.
But habitat fragmentation continues unabated, severing important habitat links that permit movements of large mammals such as elephants and tigers (Johnsingh et al. 1990; Johnsingh and Williams 1999) across the landscape and between protected areas. Road construction erodes the steep, fragile slopes and is invariably followed by human settlements because of the easier access. Grazing of cattle and other livestock is widespread. The threats to the Chila-Motichur corridor, critical for maintaining genetic exchange among elephants and tigers within their range in northwestern India, exemplifies the prevalent widespread threats. The habitat within this corridor has been degraded by settlements, overgrazing by domestic livestock, and invasions by exotic weeds (Johnsingh et al. 1990).
Justification of Ecoregion Delineation
In a previous analysis, Rodgers and Panwar (1988) identified conservation units in India and placed the moist deciduous forests along the upper Gangetic valley in the Upper Gangetic Plains biotic province (7A). We retained this unit and represented it with the Upper Gangetic Plains Moist Deciduous Forests [IM0166]. The Upper Gangetic Plains Moist Deciduous Forests [IM0166] lie within Udvardy's Indus-Ganges monsoon forest biogeographic province.
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