Tiger prey base shrinking as weeds eat up grasslands, finds census

Some bad news looms large for tiger conservationists. They predict a dip in the tiger population in the state's forests. The danger is neither from poachers nor have conservation efforts been found wanting.

But the herbivore population in the forests, the prey for the big cats, is on the decline, thus ringing alarm bells for tiger numbers.

Conservationists and forest department officials have found that the population of Gaurs, Sambar Deer and Spotted Deer has come down. The census, this time, also focused on herbivore numbers.

"While volunteers and staffers focused on tigers, enumerators did not forget to keep a count of the herbivores too. They are the prey base for the big cats and so, have an effect on the big cat population.

"Lantanna and weeds have eaten up the natural grass, due to which the herbivore population has dropped. It has also been observed that herbivores have moved to other places as they are not territorial," said a senior forest department official.

This is one of the major findings of the ongoing tiger census-2018 thus far. It is expected to be a key observation in the census report. Officials of the Project Tiger and Ministry of Environment and Forests (MoEF) officials have taken note of it.

Forest personnel have noted that the growth of lantanna and other weeds has increased from 40% to 60% in BRT, Bandipur, Nagarahole and other forests.

Retired forest official S G Neginhal also concurs. He said it was for the first time that there has been such a drop in herbivore population. The carnivore-herbivore ratio plays a crucial role. A tiger requires at least two spotted deer a week.

If the animal is large, one is enough, like a Sambar deer. But if the animal is small, like a manjak or wild boar, more of the prey are needed. To maintain a balanced wildlife, it is important to understand this science, Neginhal said.

Forest officials point out that funds crunch is a major hurdle for them in clearing weeds.

Funds allocated

"Around Rs 20 crore was allocated under the Mahatma Gandhi National Rural Employment Guarantee Scheme, but the MoEF asserts that this fund could not be used for clearing weeds.

We are trying to explain to them that clearing weeds will increase the forest's carrying capacity and will ensure that there is lesser man-animal conflict on the fringes of the forest," the officer said.

When weeds are permanently cleared, fodder will increase, ungulates will increase, thus having a chain effect of an increase in the population of elephants and tigers.

The chances of young tigers moving to the fringes of the forest will also come down. One tiger can have a territory of 5 sqkm. At present, it is 6-7 sqkm, the officer explained.