“Loss of reproduction owing to disturbance on account of heavily-used infrastructure like highways” is one of the reasons for decline of tiger population, Environment Minister Jayanthi Natarajan said in the Lok Sabha on Monday.

She told Bhausaheb Wakchaure in a written reply that the general causes also include mortality of wild animals due to poaching, degradation of forest status outside tiger reserves owing to human pressure, livestock pressure and ecologically unsustainable land uses.

Fragmentation leading to loss of gene flow from source populations coupled with mortality of wild animals due to man-animal conflict is also creating problems in tiger population growth.

Besides lack of adequate protection, loss of forest quality in terms of prey-biomass to support large carnivores like tigers and leopards is also among one of the causes for the decline of their numbers.

The Minister also cited insurgency and law and order problems in some tiger reserves as one of the causes.

Mrs. Natarajan, however, said the country level tiger population, assessed once in every four years using the refined methodology, has shown an increasing trend.

The findings of the second countrywide assessment of the status of tigers indicate a countrywide 20 per cent increase in the number of tigers in the year 2010 with an estimated number of 1706, she said.