Scientists find 75-90% decline in Leopard population in India

India’s leopard population may be only a tenth of what it was a little over a century ago, experiencing catastrophic declines due to human pressures. Given the threats the animal faces today–ranging from conflicts with humans, poaching, habitat loss to availability of prey–a group of scientists with new insights on loss of leopard abundance say that an initiative similar to ‘Project Tiger’ is required for the cat.

The leopard population, perceived to be stable due to broad geographic distribution, suffered a possibly human-induced population decline of 75% to 90% between 120 and 200 years ago, the scientists propose, in a research paper titled, ‘Genetic analyses reveal population structure and recent decline in leopards (Panthera pardus fusca) across the Indian subcontinent.’ The research findings were published in the journal PeerJ – Life and Environment on Friday.

Scientists from the Centre for Wildlife Studies (CWS India) and the Wildlife Institute of India (WII) used genetic data from leopards from across the Indian subcontinent to investigate population structure and patterns of decline. They investigated the demographic history of each identified sub-population and compared genetic decline analyses with countrywide local extinction probabilities, a press release said.

Photo Credit: C.V. Subrahmanyam

The study authors argue that the population decline in a species seen as wide-ranging and locally abundant suggest that leopards demand conservation attention just like tigers. “While we are unable to corroborate these population decline patterns with leopard census data, our results suggest that it will be important to generate such ecological abundance estimates for leopard populations in the near future,” they say. 

According to the paper, many large carnivores, which maintain the stability and functioning of ecosystems, face declining population sizes due to natural and human pressures. The leopard, probably the most widely distributed and highly adaptable large felid (a member of the cat family) globally, is still persisting in most of its historic range, but there is a lack of sub-species-level population data on country or regional scale.

Authors Supriya Bhatt, Suvankar Biswas, Bivash Pandav and Samrat Mondol from WII, and Krithi K. Karanth from CWS India, collected faecal samples from the Terai-Arc landscape of northern India and identified 56 unique individuals using a panel of 13 microsatellite markers, and merged this data with those of 143 other leopard individuals. 

Four sub-populations

They investigated the demographic history of sub-populations and compared genetic decline analyses with countrywide local extinction probabilities. “Our genetic analyses revealed four distinct sub-populations corresponding to Western Ghats, Deccan Plateau-Semi Arid, Shivalik and Terai region of the north Indian landscape, each with high genetic variation. Coalescent simulations with microsatellite loci revealed a possibly human-induced 75% to 90% population decline between 120–200 years ago across India,” the paper contends.

Detailed, landscape-level ecological studies on leopard populations are needed for future conservation efforts, it suggests.

For genetic studies, faecal samples from both tigers and leopards were collected from Uttarakhand, Uttar Pradesh and Bihar from 2016-2018 and 56 of them were identified as distinct individuals. 

“The Deccan Plateau-Semi Arid, Shivalik and Terai sub-populations show 90%, 90% and 88% decline in population size, respectively, whereas the Western Ghats sub-population shows relatively less (75%) decline in population size,” the researchers say.

Unlike the tiger census held once in four years, there is no dedicated census for the leopard. However, a leopard count accompanying the tiger census of 2014 estimated its population to be 12,000-14,000 with about 8,000 in the vicinity of tiger habitat.