SARISKA (India): Visitors who flock to India’s tiger reserves have only one question of each other: “Did you see a tiger?” Most leave disappointed, never mind the herds of elephants, deer and other ungulates that crowd the verdant forest floor. Only if a tiger was sighted is the trip deemed a success.

But tigers have become few and far between in India’s specially designated national parks and sanctuaries. A flourishing illegal trade in tiger parts mainly in China and East Asia has led to indiscriminate poaching in India’s protected tiger reserves.

In 2005, wildlife officials in the Sariska Tiger Reserve (STR), 160 kilometres north-west of Delhi, were shocked to discover poachers had wiped out the entire tiger population. Until then the forest department had been claiming there were around 22 tigers in the sanctuary spread over 881 sq. kms in the state of Rajasthan.

Three years later, the tigers have not returned to Sariska. But there is a thriving leopard population, according to forest officials.

“One aftermath of the unfortunate annihilation of tigers in the Sariska Tiger Reserve, is that leopards and hyenas are thriving there. Secondly Sambhars (deer) and Nilgais (antelopes) have multiplied manifold,” observes R.N. Mehrotra, the principal chief conservator of forests of the Rajasthan Forest Department.

This is not a bureaucratic pipedream; it makes ecological sense. “Tigers exercise a dominant influence on ungulate prey numbers. Their elimination will alter the ungulate community composition and in turn affect the structure and functioning of plant communities also,” says Dr Ullas Karanth, renowned wildlife biologist in Bangalore who is with the Wildlife Conservation Society, a New York-based wildlife advocacy and conservation group.

Prey base is a technical term that refers to the broad spectrum of herbivores that form the basis of prey for the carnivores. These include most ungulates like Sambhars (Cervus timorensis, Nilgais (Boselaphus tragocamelus), Bisons (Bos gaurus), spotted deer (Axis axis), and other antelopes. These prey base species are found only in endemic biodiversity rich areas where they can thrive. That explains why despite the presence of virgin forests in many equatorial regions, tigers are found largely only in India.

“My research shows that where prey in different size classes are abundant, tigers and leopards focus on different prey types thus facilitating their coexistence … another essential element is availability of trees that leopards can climb to escape from tigers ... where these two conditions are not met, tigers tend to exclude leopards or reduce their densities greatly… on the other hand in places like Nagarhole (National Park) where such conditions exist, both cats can thrive…”says Dr Karanth.

Dr Y.V. Jhala, senior wildlife biologist at the well-known Wildlife Institute of India (WII) in Dehra Dun, corroborates his thesis. “Yes, (leopards are indeed thriving), exact number is difficult (to estimate) but a density of about 15 leopards per 100 sq. km. is achieved in Sariska in the absence of tigers,” he says.

That would mean there are approximately 120 leopards in a protected area of 881 sq km in Sariska Tiger Reserve. “Depending on its prey availability leopards can thrive in a range of 20 sq km to 100 sq km,” confirms Karanth.

In May 2005, the WII undertook a digital pugmark method to estimate leopards’ numbers. A study states: “Out of 1,205 plaster casts only 537 were subjected to further analysis by a team of wildlife managers. Based on this analysis it is estimated that the leopard population in STR ranges from 51 to 55 individual leopards.”

Given the absence of tigers, could its prey like Sambhar and Nilgai population explode unchecked? Nilgais and Sambhars are indeed thriving and their visibility has increased in the Sariska Tiger Reserve. But anecdotal evidence cannot be extrapolated scientifically. What if the Sambhar population leads to a super abundance? Dr Jhala dismisses the speculation of super abundance with “rarely do predators control prey populations”.

Another reason for leopards to thrive now in the absence of tigers is its psychological make up. Unlike the tiger, the leopard is a major coward. The sight of anything other than wildlife sends it pell-mell.

While the habitat for both the big cats is largely the same, there was a great potential for titanic clashes between the two in the same home! Leopards do not need thick forests as habitat. They can survive in rocky terrain, scrubby jungles, and even in the plains, plateaus, etc.

In the past decade, India has lost more leopards than tigers. An August 2006 report of the Wildlife Protection Society of India says parts of 2,766 leopards were recovered in various raids and seizures. The same report explains further that body parts from 783 tigers and 777 otters were also recovered in raids and seizures till then.—Dawn/The IPS News Service