Cutting-edge research carried out by scientists from Wildlife Conservation Society India (WCS-India), in collaboration with the Forest Department, Assam, is paving the way for reliable estimation of Asian elephant populations.

In a multi-authored article published in Scientific Reports, an international journal of the high-impact Nature Research family, Dr. Varun R. Goswami and colleagues highlight how systematically documented photographic identities of individual elephants, when combined with advanced spatial capture-recapture models, present a reliable approach to estimate Asian elephant populations. This is the first study of its kind in the Northeast India region.

Capture-recapture is an advanced method that uses systematic tracking of individually identified animals to estimate population numbers while accounting for the possibility of missing animals during surveys.

“Our study pioneers the use of photographic spatial capture-recapture to estimate all segments of an Asian elephant population, including the largely solitary adult males and the herd-living adult females and younger elephants,” said Dr. Goswami, a senior scientist at WCS-India who leads the Asian elephant and Northeast India programs for the organisation. “The approach also provides fascinating insights into fine-scale space use and movement of elephants in the dynamic floodplain ecosystem of Kaziranga National Park, our study site,” he added.

The world renowned Kaziranga National Park is home to diverse and abundant assemblage of wild herbivores, including the largest population of the greater one-horned rhinoceros. This assemblage supports one of the highest densities of tigers worldwide.

“Kaziranga National Park is celebrated internationally for the success with which its rhino population has been revived and a variety of threatened species are protected,” said co-author Mr. M. K. Yadava, IFS, who is Additional Principal Chief Conservator of Forests (Research Education and Working Plans), Assam. “It is critical that populations of priority conservation species, such as Asian elephants, be reliably monitored in parks like Kaziranga for informed management decisions and to adaptively strengthen conservation efforts. It would greatly aid in understanding the increased human-elephant conflicts in the State. However, this is just a small beginning.”

Periodic flooding of the Brahmaputra River that forms the northern boundary of Kaziranga National Park makes it necessary for wildlife to move between the park and habitats to its south.

Said Dr. Divya Vasudev, a senior scientist and connectivity specialist who co-leads the Northeast India program for WCS-India: “An exciting aspect of using spatial capture-recapture models is that it allowed us to not just estimate how many elephants are in the park, but also account for those elephants that may have moved in and out of the park from neighbouring habitats. Conservation strategies for Kaziranga National Park must consider the larger landscape of which it is a part.”

Added Dr. Goswami: “Landscape-scale conservation is particularly important for wide-ranging species like the Asian elephant. Conserving such species at large spatial scales hinges very critically on science-based policy, a clear long-term vision, and the ability to consider diverse challenges and opportunities that heterogenous landscapes present.”

Said Ms. Prakriti Srivastava, IFS, who is the Country Director of WCS-India: “Our scientists and conservationists are spearheading efforts to safeguard threatened species and their habitats across the country. We remain committed to furthering this cause with passion and dedication.”

The article: “Towards a reliable assessment of Asian elephant population parameters: the application of photographic spatial capture-recapture sampling in a priority floodplain ecosystem,” can be accessed at