India ? India’s population of wild tigers, which wildlife experts have long warned is on the decline, is dramatically lower than previously believed, according to preliminary results of an exhaustive study of tiger habitats released Wednesday.

The study, conducted over the past two years by the government-run Wildlife Institute of India, found that the tiger population in some states may be nearly 65 percent less than experts had thought.

Full results of the study are not expected until late this year, but conservationists said the early results indicated the most recent tiger census – which found about 3,500 tigers – was far too optimistic.

Poaching and encroachment on tiger habitats have savaged India’s tiger population, which a century ago was believed to number in the tens of thousands.