A recent and alarming study from the Laboratory for the Conservation of Endangered Species (LaCONES) at CSIR-CCMB, Hyderabad, reveals a concerning truth: human activities within tiger habitats are directly harming the gut health of India’s magnificent tigers. This groundbreaking research highlights how factors like tourism, persistent livestock grazing, and other human disturbances are not just an annoyance, but a genuine threat to these big cats’ well-being and their very long-term survival.
The study delivers a stark warning: the increasing human footprint in the buffer zones of tiger reserves is silently, yet significantly, eroding tiger health, even in areas designated for protection. Scientists are now strongly advocating for much stricter regulations on tourism, grazing, and all related human activities in these crucial buffer regions. Their goal is clear: to safeguard the natural resilience and future generations of India’s national animal.
Extensive Sample Collection Across Five Reserves
To conduct this vital research, Chief Scientist G. Umapathy and his dedicated team spent two years collecting tiger droppings. Their samples came from five prominent tiger reserves across India: Corbett (Uttarakhand), Kanha and Bandhavgarh (Madhya Pradesh), Tadoba-Andhari (Maharashtra), and Periyar (Kerala). Crucially, samples were gathered from both the core (highly protected) and buffer (human-impacted) zones, spanning all three distinct seasons.
Understanding Core and Buffer Zones
Tiger reserves are typically structured into two main areas: core zones and buffer zones. Core zones are designed to have minimal human interference and very restricted tourism, usually limited to less than 20% of the area. In contrast, buffer zones are adjacent regions where human settlements, agricultural practices, livestock grazing, and forest resource collection are common. These buffer areas are typically open to tourism for nine months of the year, encompassing both summer and winter, which leads to a consistently high human presence.
Such human-induced pressures inevitably lead to increased physiological stress in large carnivores, including tigers. This stress is often indicated by elevated levels of faecal glucocorticoids, a marker of stress hormones. A thriving, balanced gut microbiome is absolutely critical for an animal’s overall health, providing robust immunity against diseases and ensuring peak physical fitness. When this delicate microbial balance is disrupted—a condition known as gut dysbiosis—it can have severe, long-lasting consequences on a tiger’s digestion, immune system, and ability to resist illness, as confirmed by the researchers.
Intriguingly, the study observed similar gut microbiomes between Kanha and Tadoba, two central Indian reserves, likely due to their close geographical proximity, shared climates, and similar habitat types. What’s more, despite being located in diverse regions, Corbett (North India), Periyar (South India), Kanha, and Tadoba-Andhari (Central India) all exhibited comparable bacterial community structures within their tigers.
“Our findings clearly show that the gut microbiome diversity in Bandhavgarh was significantly different from the other four parks studied. We also found that the gut bacterial composition changed markedly between monsoon and winter seasons, underscoring the powerful influence of seasonal environmental shifts on these microbial communities,” explained Mr. Umapathy.
He further noted that each reserve harbored its own unique bacterial genera, with some showing more distinct microbial groups than others. These variations, he stressed, are most likely driven by human-related factors such as the proximity of settlements and the presence of cattle, which can profoundly disrupt the natural gut microbial balance essential for tigers’ health.
The research team also included Gudimella Anusha, Aamer Sohail Khan, and Gopi Krishnan from LaCONES. This vital study, generously funded by the Department of Science & Technology and supported by the CSIR, has been published in the latest issue of the esteemed journal, Global Ecology and Conservation.