Historical records suggest that the four-horned antelope (Tetracerusquadricornis) was once found throughout most parts of India. Recent records however indicate a highly fragmented population, especially north of the Gangetic plains in Uttar Pradesh, Bihar, and Nepal. While Odisha and West Bengal mark the easternmost limit of its distribution, they are reported from most forest tracts in Central and Peninsular India. In the west, its distribution is restricted. It is found as an isolated population in the Gir Forest in Saurashtra, which is the only site west of Valsad and Rajpipla in Gujarat with the known distribution of the four-horned antelope (Sankar and Goyal 2004).
Although the four-horned antelope is not uncommon in many protected areas, it is always found in low density, the best density figures coming from Panna national park in Madhya Pradesh where the animal thrives (Sankar and Goyal 2004). Other areas having a good population include Kumbalgarh WLS, Rajasthan, Gir WLS, Gujrat, Pench National Park, Maharashtra, Mudumalai WLS, Tamilnadu and Dhaknakolkaz WLS, Maharashtra (Sankar and Goyal 2004).
Recently (2019) a biodiversity assessment was conducted by Wildlife Institute of India, Dehradun in Gautam Buddha Wildlife Sanctuary (GBWLS), Bihar. The Sanctuary encompasses 259.5 sq km at the border of Bihar (138.4 sq km) and Jharkhand (121.14 sq km). Gaya and Hazaribagh Forest Divisions collectively manage the Sanctuary. The GBWLS is situated in the Deccan peninsula-Chota-Nagpur (6B) biogeographic province.
The refuge covers portions of the Lower Gangetic Plains moist deciduous forests and Chota Nagpur dry deciduous forests ecoregions. Plant communities include dry and moist sal (Shorearobusta) forests, ravine thorn forest, and tropical dry riverine forest.
Results and Discussion
During fieldwork, the presence of four-horned antelope was recorded for the first time near Bukar village, situated at an Eastern boundary of the GBWLS (Fig. 1). The animal was captured at a location near the western boundary of the GBWLS (Fig. 2). We also collected the pellet sample as evidence of the animal from the Sanctuary.
GBWLS lies at the border between Bihar and Jharkhand, with Koderma and Hazaribagh Wildlife Sanctuary in its proximity. Both these Sanctuaries (Koderma and Hazaribagh) could work as a source population of the four-horned antelope in GBWLS, but their presence has never been reported in the past (All India Tiger Census report 2006). Further away, two protected areas–Valmiki tiger reserve in Bihar and Palamau tiger reserve in Jharkhand are located. The Valmiki tiger reserve has poor connectivity with the GBWLS being approximately 340 km away. However, the Palamau tiger reserve is well connected with the GBWLS through the Lawalong Wildlife Sanctuary, Hazaribagh Wildlife Sanctuary, and Koderma Wildlife Sanctuary, situated at a distance of 162 km from GBWLS.
Valmiki’s poor connectivity and sparse animal population cannot serve as a source for animals in GBWLS. The dispersal is more likely from the Palamau tiger reserve. There is however no data available on the home range or dispersal pattern of the animals, hence nothing can be ascertained for sure. There is also a possibility that the adjoining protected areas have a diverse animal population. The lack of periodic and scientific animal census by the forest officials of both Bihar and Jharkhand has resulted in this poor estimate.
The sighting of the four-horned antelope in the GBWLS provides hope and an excellent opportunity for the retention and conservation of species in this landscape. According to the IUCN Red List, the total population size of the four-horned antelopes is above 10,000 individuals, although its numbers are understood to be declining. Currently, this species is classified as Vulnerable (Vu) on the IUCN Red List (IUCN 2017).
The habitat condition of the GBWLS and the protected areas present in its proximity is suitable for sustaining the four-horned antelope. Earlier study suggests that animals prefer the dry deciduous open forest, especially forests resplendent in flora such asZiziphusmauritiana (Ber), Bauhinia racemosa (Indian Bidi Tree), Emblica officinalis (Amla), and Acacia leucophloea (Safed Kikkar), Terminalia tomentosa (Marda), Boswellia serrata (Salai) and Lanneacoromandelica (Ash Tree) (Sankar and Goyal 2004). GBWLS, Koderma WLS, and Hazaribagh WLS are therefore all appropriate habitats. A well-calibrated assessment is needed in GBWLS and in the adjoining protected areas to know the actual numbers so that a plan of management could be formulated for conservation.
India’s four-horned antelope is the least studied so far, with little available information (Prater 1980; Rahmani 2001). The species is protected by Indian law, and it is listed in Schedule I of the Wildlife Protection Act, 1972. Awareness about the species and information access to park managers and decision-makers about its specific requirement in terms of habitat is needed for its long term survival. More scientific research is also required with an emphasis on the four-horned antelope’s evolution, population viability, habitat selection, and relationship with sympatric species.
International Union for Conservation of Nature (IUCN). 2017. Four Horned Antelope: Tetracerusquadricornis. Available at: https://www.iucnredlist.org/species/21661/50195368
Prater S. H. 1980. The book of Indian animals (Bombay Natural History Society), New Delhi: Oxford University Press.
Rahmani A. R. 2001. India, in Mallon D.P. and Kingwood S.C. (compilers) Global Survey and Regional Action Plans: Antelopes: Part 4: North Africa, the Middle East, and Asia, Switzerland and Cambridge: International Union for Conservation of Nature (IUCN).
Sankar K. and Goyal S. P. 2004. Ungulates of India: Wildlife Institute of India, Dehradun: India. Available at: http://wiienvis.nic.in/PublicationDetails.aspx?SubLinkId=318&LinkId=627&Year=2006