Tourism, livestock grazing impact gut microbiome of tigers, finds CCMB study

Human presence in tiger habitats is disrupting the gut health of India’s tigers, a new study by researchers at the Laboratory for the Conservation of Endangered Species (LaCONES), CSIR-CCMB, Hyderabad, has found. The study highlights how tourism, livestock grazing and other disturbances may affect the animals’ health and long-term survival.

It warns that growing human pressures in buffer zones could silently erode tiger health, even inside protected reserves. Scientists emphasise the need for stricter regulation of tourism, grazing and related activities in these areas to safeguard the resilience of India’s national animal for future generations.

Samples from 5 tiger reserves

The research team led by chief scientist G. Umapathy collected tiger droppings over two years from five major tiger reserves — Corbett (Uttarakhand), Kanha and Bandhavgarh (Madhya Pradesh), Tadoba-Andhari (Maharashtra) and Periyar (Kerala). Samples were taken from both core and buffer zones across all three seasons.

What are core and buffer zones?

Tiger reserves are divided into core zones and buffer zones. The former refers to areas with minimal human disturbance and limited tourism (up to 20% of the area) while the latter means regions with human settlements, farming, livestock grazing and forest resource extraction. These zones are open to tourism for nine months a year during summer and winter, resulting in elevated human presence.

Such anthropogenic pressures increase physiological stress in large carnivores, including tigers, as indicated by elevated levels of faecal glucocorticoids. A balanced gut microbiome is essential for maintaining health, protecting against disease and ensuring overall fitness. Disruptions to this microbial balance — known as gut dysbiosis — can have long-term impact on digestion, immunity and disease resistance, said researchers.

Among the central Indian reserves, Kanha and Tadoba displayed similar gut microbiomes maybe due to their geographic proximity, comparable climates and habitat types. Interestingly, despite being located in different regions, Corbett (North), Periyar (South), Kanha, and Tadoba-Andhari (Central) shared similar bacterial community structures.

“Our findings indicate that the gut microbiome diversity of Bandhavgarh was significantly different from three of the four other parks. Gut bacterial composition also varied significantly between monsoon and winter, highlighting the influence of seasonal changes on microbial communities,” said Mr.Umapathy.

Each reserve harboured unique bacterial genera, with some showing more distinct taxa than others. These differences are likely driven by human-related factors such as settlements and cattle presence, which can disrupt the natural gut microbial balance of tigers, he said.

Other researchers involved in the study include Gudimella Anusha, Aamer Sohail Khan and Gopi Krishnan from LaCONES. The study, funded by the Department of Science & Technology and supported by the CSIR, has been published in the latest issue of Global Ecology and Conservation.