The Terai Arc Landscape: a brief overview
The Terai Arc Landscape represents the contact zone between the Himalayas and the Indo-Gangetic plains. It forms a narrow strip stretching well over 1000 km (600 miles) across India and Nepal, from the Yamuna River in the west to the Bagmati River in the east. Within this the study area as reported here is limited to the Indian part, going no further east than Valmiki Tiger Reserve in Bihar State. The total surveyed area covers 42,700 Sq. km (16,500 sq. mls), over 900 km (560 mls) in length and 50-60 km (31-37 mls) in width.

Within the Terai Arc Landscape three narrow geographical sub-units run parallel to the main Himalaya: the Shivalik Hills, the adjoining bhabar areas, and the terai plains. At the contact with the Himalaya, the Shivaliks are made of material brought down from the Himalayas and uplifted to altitudes ranging from 750 m (2460 ft) to 1400 m (4590 ft). Next to this the babhar is hilly terrain resulting from the accumulation of coarse alluvium and boulders along the foothills, while finer material such as silt is deposited further out to form the floodplains of the terai.

Shivaliks and bhabar originally presented a dense cover of deciduous forest, while the terai floodplains are the domain of savannahs and grasslands. Famous for harbouring some of the tallest grasses in the world (up to seven m (32 ft), these grasslands also support the highest densities of tigers, rhinos and ungulates in Asia.

Conservation issues in the Terai Arc Landscape
The Terai Arc Landscape has been identified as priority landscape by the World Wildlife Fund (WWF), one of three areas in the Indian sub-continent for immediate attention to save wild tigers. The ‘Terai-Duar Savannas and Grasslands’ are also one of the Global 200 Ecoregions.
According to WWF, “this ecologically important region is faced with loss of habitat and its fragmentation due to a variety of threats. Chief among those are population pressure on natural resources and erratic developmental activities in the region. Both have resulted in the decline of forest cover and loss of biodiversity. While parts of the Terai are reduced to tenuous linkages that connect relatively large remaining wildernesses, in some places these linkages are being lost and need restoration to halt further degradation of these natural habitats” (cf. links to WWF as provided in this page).

Figures given in the study reported on here show that the Indian part of the Terai Arc Landscape is one of the most densely populated regions of the country. A 2001 census gives a total population of 23,894,443 and a density of 543 inhab./sq km (national average 324 inhab./sq km). In addition population is growing fast, with an increase of 54% between 1981 and 2001. The great majority of the population is rural and engaged in natural resources-based occupations, and there is a heavy reliance on subsistence fuels such as firewood and dung. The settlement pattern has been largely influenced by land accessibility and soil arability. As a result most of the terai plains have been taken over by agriculture, the remnants being very fragmented and covering a total of under 500 sq km (193 sq mls). Most of the forest cover is in the hilly babhar and Shivaliks.

Survey aims and methodology
The study reported on here was carried out between 2002 and 2004. Two major aims were (i) to assess tiger (Panthera tigris) and large ungulate distribution and status, and (ii) to document the socio-economic conditions of the local people and major disturbance factors.

Field sampling for tiger presence, prey availability and disturbance factors was carried out along pre-determined transects by teams made of biologists, field assistants and forestry staff. A total of 246 transects, each from 3 to 9 km in length for a total of 1001 km, were surveyed in the entire Terai Arc Landscape.

The presence of tigers as well as other carnivores such as leopard and black bear (Ursus thibetanus was recorded from evidence such as pug marks, scat and scrape marks.

On the same transects, the presence of prey species was recorded from indirect evidence (tracks, pellet groups) as well as direct observation.

On the same transects again, disturbance signs such as dung and sightings of livestock (cattle and buffalo), tracks and sightings of domestic dogs and people, lopping and cutting signs were also recorded.

Location of tiger habitats
Tiger is no longer found throughout the Terai Arc Landscape. Instead its habitat has been fragmented and is now made of separate blocks of varying sizes and configuration. Wherever the forest is heavily fragmented and anthropic pressure is strong, tiger has been extirpated. The Indian part of the Terai Arc Landscape has nine such blocks, but when Nepal is included and the Terai Arc Landscape is viewed as a whole, fragmentation is reduced to five larger units (tiger units or TUs). TU I, II and III are mostly in the state of Uttaranchal (India), in the bhabar landscape domain. TU IV is largely in Nepal and TU V is spread along the Nepal - India border (states of Uttar Pradesh and Bihar), both in the terai landscape domain. Thanks to disturbance, in each unit tigers effectively use less that 50% of the total area. But each unit also presents at least one “key patch” where a “source population” of tiger appears to be more persistent. These key patches include the western portion of Rajaji NP in TU I, Corbett TR in TU II, Pilibhit FD-Sukhlaphanta Reserve-Kishanpur WLS-Dudhwa NP-Bardia NP in TU IV and Chitwan NP in TU V (see maps in this page - also use link provided in Recommended websites to display in Google Earth the location of the surveyed tiger habitats).

Threats to tiger survival and action for future conservation
In order to combat habitat fragmentation and establish strong source populations which can then contribute to maintain tiger throughout the Terai Arc Landscape, the authors advocate the creation of two large blocks of contiguous tiger habitat by creating or improving connection corridors between existing tiger units. The first of these two blocks would cover 8000 sq km (3090 sq mls) of bhabar landscape between the Yamuna and Sharda Rivers (including Rajaji and Corbett National Parks) and provide the largest contiguous tiger habitat in the Himalayan foothills. Similarly, a large block of terai habitat would be secured by connecting Pilibhit FD-Kishanpur WLS and Sukhlaphanta Reserve, Nepal.

However the authors also identify a number of measures that need to be taken, especially in the western bhabar zone, to alleviate the current threats facing tiger conservation and which may negate the benefit of any such habitat interconnection. These actions include:
- combat poaching,
- prevent encroachment,
- provide alternative sources of firewood, and develop the use of more efficient stoves,
- relocate villages and industrial sites,
- improve trans-border cooperation,
- ban sand and boulder mining in important corridor areas,
- develop conservation education and awareness.

information source
Johnsingh A.J.T., Ramesh K., Qureshi Q., David A., Goyal S.P., Rawat G.S., Rajapandian K. and Prasad S., 2004. Conservation status of tiger and associated species in the Terai Arc Landscape, India. RR-04/001, Wildlife Institute of India, Dehradun, Pp. viii + 110. (cf. link provided to report online, Wildlife Institute of India website and more).