3 days ago
Explained: State of India's tiger prey, why challenges to their habitat need to be addressed
For the first time, a detailed assessment of the status of ungulates (hoofed mammals), including deer, pigs, antelopes, and bison, has estimated their abundance across India. It has revealed a decline in their populations in several states and highlighted conservation challenges, such as habitat loss and deforestation.
The findings are crucial for the conservation of India's tigers and forests, as ungulates form the core prey base of the striped cat and other large predators. India currently has more than 3,600 tigers, accounting for 70% of the world's tiger population. Additionally, the animals help regulate forests and soil health with their feeding habits.
The National Tiger Conservation Authority and the Wildlife Institute of India prepared the assessment report, using data from the 2022 All-India Tiger Estimation exercise to estimate the animals' distribution and density.
India's tiger prey base, mainly comprising the chital (spotted deer), sambar (large deer), and the vulnerable gaur (Indian bison), presents a highly uneven distribution across forest landscapes. The report drew on extensive direct and indirect evidence, like field surveys, camera traps, and dung signs collected during the 2022 estimation exercise.
According to the findings, spotted deer, sambar, and gaur populations are thriving in large parts of the country, but declining in east-central India in Odisha, Jharkhand, and Chhattisgarh. The signs of prey decline and low density are due to severe habitat degradation, infrastructure development and mining that fragments forests, left-wing extremism, and subsistence hunting by residents.
Forests in Uttarakhand, Western Ghats, central India and the northeast have a fairly healthy population of ungulates. However, small and isolated populations of species such as barasingha, wild buffalo, pygmy hog, and hog deer face bottlenecks in their genetic diversity, with habitat fragmentation preventing the intermixing of different animals.
The core tiger prey species are abundant, especially within tiger reserves and national parks, but not so much in sanctuaries that receive a comparatively lower level of protection, and even less in forest divisions abutting tiger reserves.
Health of different species
The chital (spotted deer) remains the most abundant ungulate across Indian forests. Its wide distribution and ability to thrive in a variety of habitats, including forest edges and agricultural interfaces, make it a key prey species for tigers.
The population of the sambar, another crucial prey animal, remains stable across most tiger landscapes, particularly in central India and the Western Ghats. The wild pig, an adaptable species, is also found in good numbers across regions.
The Nilgai and the gaur show healthy populations in many areas. Nilgai, India's largest antelope, is highly adaptable and often ventures into farmland, while gaur prefers dense forests and uneven terrain, and is especially abundant in the Western Ghats and parts of central India, Eastern Ghats, and northeastern Himalayan foothills.
In contrast, species with narrow ecological preferences are faring poorly. Populations of the hog deer, which live in grasslands and floodplains, have significantly declined due to the destruction and fragmentation of their preferred wetlands and swamp habitats. Their current distribution is confined to isolated patches in the Terai grasslands and floodplains of the Ganga and Brahmaputra.
Similarly, the once widespread barasingha or swamp deer is now limited to select locations such as Kanha, Dudhwa, and Kaziranga. Despite some successful reintroduction efforts in Bandhavgarh and Satpura, the species remains vulnerable due to its dependency on specific wetland-grassland ecosystems.
Significance for tigers
Loss of habitat, especially quality habitat, competition with livestock and humans, conflict with humans, deforestation, development projects and subsistence hunting are some of the key challenges to the ungulate population. A fall in their numbers affects the ecological balance of forests both inside and outside tiger reserves.
The lack of prey base is also a double whammy for tigers, impacting the existing tiger occupancy and forcing them to kill livestock and smaller species.
Secondly, tiger-abundant regions such as Maharashtra and Madhya Pradesh are nearing their capacity to sustain their wildlife population with available resources (what is known as 'carrying capacity'). As a result, tigers often wander towards the east-central states, but struggle to occupy the forests due to poor prey base and other pressures on the ecosystem. These states have a high potential to harbour a substantial tiger population, but it will be contingent on improvements in habitat and prey, and stepping up their protection.
Another direct fallout of low prey base is tigers moving beyond the reserves to hunt livestock, putting them in closer contact with humans, who kill tigers in retaliation for livestock depredation. In states like Uttar Pradesh, Bihar, Maharashtra, Rajasthan, Madhya Pradesh, ungulates such as wild pigs and nilgai often damage crops, adding another dimension to the human-wildlife conflict due to the loss of wild habitats. A major concern is the conversion of swampy grasslands, seasonal wetlands, and floodplains into urban settlements or farmlands.
Linear infrastructure, such as highways, railways and power lines, can fragment the contiguity of ungulate habitats, disturbing the survival of wildlife, as well as forest dynamics. The report prescribes augmenting prey populations through on-site breeding in enclosures to protect them from predators.
