Decline in tiger prey due to civil unrest, deforestation, poaching: New report

Wildlife Institute of India raised concerns over shrinking population of species like chital, sambar, and gaur in more than a quarter of India’s tiger habitats

Guwahati: A recent report by the Wildlife Institute of India (WII) on ungulates — hoofed mammals that serve as key prey for carnivores — has raised concerns over the shrinking population of species like chital, sambar, and gaur in more than a quarter of India’s tiger habitats, citing rising civil unrest and human-wildlife conflict as major causes.

Ungulates play a key role in sustaining large carnivores like tigers and leopards and medium ones like hyenas and jackals (Abhimanyu Singh Rajvi/ Representational image)

“Ungulates play a key role in sustaining large carnivores like tigers and leopards and medium ones like hyenas and jackals. A thriving ungulate population sustains these carnivores, which in turn play a vital role in regulating the predator-prey dynamic essential for maintaining ecological balance,” the report uploaded on the WII website last week said.

Chital, sambar, and gaur are key prey species in the tiger’s diet. “Chital, sambar, and gaur exhibit similar population trends with approximately 27% of sites showing a decline. This correlates to an increased probability of livestock depredation in these areas,” the report said.

The report, based on the first-ever study on the status of ungulates conducted by the National Tiger Conservation Authority (NTCA) and the Dehradun-based WII, using data from the 2022 tiger census, highlights multiple threats faced by these hoofed mammals. These include habitat loss due to deforestation, urbanisation, and agricultural expansion, as well as poaching and the decline of livestock. Human-wildlife conflict, particularly crop raiding by certain ungulate species, often leads to retaliatory killings, further contributing to their population decline.

A total of 39 species of ungulates are reported in India. Chital, sambar, wild pig, nilgai, barking deer, and gaur are the most abundant herbivorous ungulate species and are widely distributed across India, unlike other ungulate species which have much smaller and specialised fundamental niches.

The report mentioned that densities of 30 or more prey per square kilometre can support over four tigers per 100 square kilometres, and this tiger density scales with increasing prey availability.

“In Odisha, both prey and tiger densities are low. High bushmeat consumption and civil unrest in the region negatively impact wildlife presence, leading to low ungulate densities,” the report read.

Similarly, “Palamau (tiger reserve in Jharkhand), an important part of the Central Indian corridor, faces challenges such as left-wing extremism, which affects wildlife presence. The area has very low ungulate and leopard densities and has not had a resident tiger population for more than a decade,” it added.

Maharashtra tiger reserves, particularly Tadoba, and in Ratapani of Madhya Pradesh, carnivore presence is high, whereas prey density remains low. As a result, these areas experience high rates of livestock depredation, leading to increased human-wildlife conflict.

Similarly, tiger reserves like Nagarjun Sagar (Andhra Pradesh) and Amarabad (Telangana) show a rapidly increasing tiger population but low prey density. Without prey recovery and supplementation, human-wildlife conflict in this region is also expected to rise rapidly, the report said.

The report also mentioned that the Valmiki-Sohagibarwa landscape (in Bihar and Uttar Pradesh respectively) has a high human population density alongside an increasing tiger population. “Without a proper ungulate population recovery plan, this landscape may experience heightened conflict between carnivores, livestock, and humans,” the report added.

The study found a decline in the populations of chital, sambar, and gaur in 28%, 27%, and 28% of tiger habitats in India, respectively, between 2014 and 2022. The populations of the three species were found either stable or showed an increase in the rest of the tiger habitats during the same period.

Areas with high densities of these ungulates often support higher tiger densities. When preferred prey is not available, tigers shift to smaller prey such as wild pigs or barking deer, the report added.

“As prey densities increase, tiger densities rise sharply, reflecting the critical role of prey abundance in supporting predator populations. However, beyond 75 prey per square kilometre, the curve plateaus, indicating diminishing returns where additional prey no longer correlates with higher tiger densities,” the report said.