When a wildlife census in Chitwan National Park in 2013 counted 120 tigers, conservationists were elated. It meant Nepal was well on its way to doubling its tiger population by 2022 as per an international target.
But in 2018, the number of tigers surprisingly fell to 93, owing to male tigers getting into fights over territory. Ecologists feared that the park was getting too crowded, and it had reached a saturation for the number of tigers it could accommodate and there was fear of human-animal conflict.
An adult male tiger needs at least 100sq km to roam in, while a female needs about 20 sq km. Each adult needs to make at least one kill of a deer-sized animal a week.
The debate compelled the Department of National Parks and Wildlife and Nature Conservation to study the carrying capacity of Chitwan and the adjoining Parsa National Park, where there was actually an increase in tigers in the 2018 count.
Now, a new study titled ‘Assessment of Ecological Carrying Capacity of Royal Bengal Tiger in Chitwan-Parsa Complex, Nepal’ that studied prey density and tiger territory has found that Chitwan and Parsa combined can actually hold at least 175 tigers.
“Under natural conditions, Chitwan has a carrying capacity of 136 tigers and Parsa can hold 39,” said Haribhadra Acharya, an ecologist from the Department involved in the study. “At present, there are 93 tigers in Chitwan, 90 in Bardia and 18 in Parsa.”
The study examined how much prey meat a tiger needs in a day, which they estimated to be 6kg, and that totals an average of 2,000kg of meat a year. In protected areas, 15% of prey species are usually hunted for food by carnivores annually, of which tigers alone account for 10%, the study found.
Extrapolating these numbers, the researchers calculated that there needed to be prey species with 20,000kg of meat roaming in a 100sq km area of an adult tiger’s territory. This is when they came to the conclusion that Chitwan and Parsa National Parks have enough meat on hooves for more tigers.