What has been feared by nature-lovers, especially those enchanted by tigers, has come true. A large influx of tourists into the tiger reserve forests across the country can cause stress to the big cats.

A study conducted by the Centre for Cellular and Molecular Biology (CCMB)’s Laboratory for Conservation of Endangered Species (LaCONES) revealed tourism-induced stress in tigers in two major tiger reserves in the country.

Published in Conservation Physiology, the study examined the relationship between anthropogenic disturbance (pollution due to human activity) and physiological stress levels among two tiger populations in central India in Bandhavgarh (BTR) and Kanha Tiger Reserve (KTR) in Madhya Pradesh.

Researchers assessed concentrations of fecal glucocorticoid metabolite (fGCM) – a marker of stress in individual tigers. Chronically elevated glucocorticoid levels can negatively impact growth, reproductive success, immunity and cause muscular atrophy.

The study team collected a total of 341 fecal samples from both the reserves during tourism and non-tourism periods and data on various anthropogenic disturbances, including tourism activities such as the number of vehicles and visitors. It found significantly higher fGCM concentrations in tigers at both the reserves during tourism period compared to the non-tourism period.

A significant correlation was also found between fGCM concentrations and the number of vehicles/disturbance level in these tiger reserves. The study suggests that “unsustainable wildlife tourism causes distinct physiological stress in tigers in protected areas”.

Previous studies from the same research group had shown that newly-introduced tigers in Sariska Tiger Reserve, Rajasthan, had failed to reproduce effectively, presumably due to high levels of stress caused by high anthropogenic disturbance.

The study recommends a strict regulation of vehicular traffic, the number of tourist vehicles, shifting of artificial waterholes away from tourist roads and reducing other anthropogenic disturbances, including relocation of villages from the core area of tiger reserves.

India harbours 60% of the current global free-roaming tiger population. But they suffer from threats like poaching, habitat loss and fragmentation. It has lost more than 95% of its global historical home range and its extant population exists in fragmented habitats.