Kerala’s forest cover may be extremely fragmented and prone to recurrent human-animal conflict, but it continues to be home to a thriving tiger population, an extensive study by the state’s forest department shows.
Conducted over the course of a year in 2017-18, the All Kerala Tiger Monitoring Programme identified a total of 176 inpiduals, 75 of them within the confines of the Wayanad Wildlife Sanctuary (WWS) alone, based on camera-trap images. In fact, the WWS, part of a large forest complex in the Western Ghats, could hold the single largest population of the big cat in the country and perhaps even in the world. The Periyar and Parambikulam Tiger Reserves recorded 25 inpiduals each.
At a time when tigers in India are faced with stark challenges with respect to habitat loss and poaching, these numbers from the forest department study are affirmative. While the study was conducted in all forest pisions, including areas outside of tiger reserves, not all locations in these pisions could be covered, due to a variety of reasons. For example, the forest pisions north and south of Nilambur in Malappuram district are considered to support a good population of wild cats, but owing to Maoist threats, camera traps couldn’t be installed in these pisions. An abstract report of the study said if camera traps were to be deployed systematically in all forest pisions without gaps, the tiger population would have crossed 200 in the state.
"The objective of the study was to find out if tigers are present in all the forested regions of Kerala, and if so, what’s the approximate numbers and how healthy the forest ecosystem is. It also indicates what course of action we need to undertake to protect this ecosystem," said BN Anjan Kumar, chief conservator of forests (wildlife), who headed the team, said.
"From this study, we can point to certain landscapes in Kerala where tiger presence has been confirmed. Since the tiger is an apex predator, it will indicate the health of the ecosystem such as the presence of a proper food chain. This helps us pert our resources and manpower to prioritize the tiger-dominated landscapes and protect the cats," he added.
It took Kumar’s team of around 500 forest officers nearly a year to set up 1640 camera trap stations covering around 9400 square kilometers of forest area in Kerala and a further six months to sort the images. The camera traps were set for a month. Locations were ascertained by thoroughly checking trek routes, forest roads and animal corridors for signs such as pugmarks, scrapes, scratches, kills and sounds. When tigers pass in front of the cameras, the sensors detect motion and the cameras are triggered to take photos. The cameras were also designed to capture presence of co-predators and prey species such as Gaur, Sambar, wild dog, leopards, mongoose, sloth bear, porcupine and pangolin. Forest guards and watchers had to sort through nearly two million photographs captured by the cameras. Inpiduals were marked and identified with the help of their stripes and coat colour.
Of the 1640 camera trap stations, tigers were captured in 369 stations (22.5%), out of which more than one inpidual was captured in 156 stations. If WWS shone through for it’s potential of hosting a big cat population, not a single tiger was recorded in forest areas under the Idukki wildlife sanctuary. Leopards were captured on 70% of the camera trap stations across Kerala, including in regions adjoining urban areas.
"Demographic simulation studies by Kenny el.al. (1995) and Karanth and Stith (1999) suggest that cubs (< a year old) may comprise roughly 25% of a healthy tiger population. Thus, the forest of Kerala is home to a total of about 250 inpiduals that should have either part of or entire home ranges within the Kerala forests," the abstract report said.