Greater One-Horned Rhinoceros

The greater one-horned rhinoceros (Rhinoceros unicornis) is commonly found only in South Asia and South East Asia. Historically, the rhinos were distributed in the floodplain and forest tracts in Brahmaputra, Ganges and Indus river valley. Today, however, no more than 2,000 remain in the wild, with only two populations containing more than 100 rhinos: Kaziranga National Park in Assam, India (1,200) and Chitwan National Park (CNP), Nepal (600). Despite joint efforts between Bhutan and India, the survival of a small population of rhinos living along the Indo-Bhutan border in Manas still remains doubtful (Jnawali et.at, 2000)

History of Rhino Conservation in Nepal

In Nepal, the rhino population was estimated at ca. 1,000 in the Chitwan valley until 1950. The area was well protected by the then Rana rulers for sport hunting. It was also secure from outsiders since malaria was rampant. Only a few indigenous communities like the Tharus , who are immune to the disease, lived there. Their impact on the natural environment was negligible.

After the collapse of the Rana regime in 1950 and the eradication of malaria during the mid-1950s, Chitwan opened to outsiders. Thousands of people cam down from the mid-hills and large swathes of wildlife habitat was cleared for human settlements, agriculture and other development activities. This not only destroyed the forest but also affected the wildlife population because of poaching. This affected mainly large mammals including rhinos and as a result, the rhino population dropped to less than 100 during the late 1960s (Adhikari et. al, 1999).

Recognizing the need to halt the decline of rapidly diminishing rhino population, Government of Nepal established the " Gainda Gasti ", an armed Rhino Patrol Unit in 1961, and declared the remaining prime rhino habitats, about 544 sq km along Rapti, Narayani and Reu rivers, as the Chitwan National Park (CNP) in 1973. The park was later extended to encompass a total area of 932 sq km and was listed as a World Heritage Site in 1984 for its high biological diversity.

After the successful effort of the Department of National Parks and Wildlife Conservation (DNPWC), the declining rhino population began to gradually increase. The CNP demonstrated that the population can rebound vigorously when sufficient habitat and protection are provided. It is an example of a population that was almost on the verge of extinction that has recovered while still maintaining a high genetic diversity.

Rhino Habitat

Rhinos inhabit the alluvial flood-plain vegetation of sub-tropical climates where water and green grass is available all year. Many rhinos now live within blocks of the suitable rhino habitat in CNP. Rhinos occurred in highest densities along the flood plain grasslands and riverine forests bordering the Rapti, Narayani, Reu, and Dhungre rivers, suggesting that floodplain grasslands dominated by 4-6 m tall Saccharum spontanium are the single most critical habitat (Dinerstein and Price, 1991). Grasslands interspersed with patches of riverine forests together make about 30% of the park area and have Saccharum spp., Narenga spp., and Themeda spp . (Shrestha, 1995). This grass species is the fundamental food resource of rhinos comprising more than 60% of the animal diet. Due to the flood and vegetation succession, the grassland may have decreased. Sal Shorea robusta forest associated with species such as Dillennia pentagyna, Syzigium cumini, Trijuga oleofera, Lagerstromia parviflora, Terminalia tomentosa, T. bellerica, and Phyllanthus emblica comprise 70% of the park area and are seldom eaten by rhinos.

Inundation by regular flooding of the alluvial plains along major rivers creates conditions favorable for the quick appearance of sprouts and germination to maintain the dominance of Saccharum spontaneum . This makes the monsoon flood very critical for maintaining rhino habitat. Oxbow lakes and other open water bodies are also important because the rhino spends about 8 hours in a day in wallows or streams during high humidity periods (August-September). In December and January, they spend at least an average of a day wallowing (Laurie, 1978).

Current Status and Distribution

Considering its endangered status, the rhino is in Appendix I of CITES (Convention on International Trade of Endangered Flora and Fauna) and is protected by Nepal's National Park and Wildlife Conservation Act (1973) in Appendix I. Studies have revealed that the population of rhinos increased from less than 100 to an estimated 270-310 by 1975 (Laurie, 1978). By 1988, the population rose to 358 (Dinerstein and Price, 1991). In 2000, that number was recorded at 612 rhinos (DNPWC Report, 2000).

Newly released census (Rhino Count 2005) figures reveal that the population of endangered greater one-horned rhinos in Chitwan National Park has dropped from 544 in 2000 to 372 - a 31 percent decline in 5 years. At least 94 rhinos were lost to poaching and 66 to natural causes such as flooding, fighting, predation and age. The increased poaching is because of the reduction in the number of anti-poaching posts from 32 to 8 due to Maoist insurgency that has changed the National security priorities and also restrictions on the movement of park staff due to the ground situation.