Green Minute News: 

One of the first studies in the world, a new ecological study has given rise to “methods and results” to save tropical forest ungulates like gaur, chital, sambar, muntjac and wild pig. Monitoring ungulate population is an essential part of Wildlife Management as they perform significant ecological role including structuring the population of Big Cats and other carnivores. Presently, a number of Ungulate species are declining and threatened globally from Asia to Africa to Americas.

This method can be used for surveys of large ungulate population across the world. Since the understanding of population ecology of mobile wildlife is very limited, this can replace the commonly accepted “line transact survey” which is now being used in India and Asia.

The new study is based on field work and analyses conducted on population ecology of five species of threatened ungulates: 

Gaur, Sambar, Chital, Muntjac and Wild Pig in the protected areas of Nagarhole and Bandipur. 

It involved the conduct of line transect surveys on foot, designed and implemented advanced distance sampling methods

The data generated were analysed using spatially explicit hierarchical distance sampling models. This is for the first time such advanced methods have been employed in the world. The study rigorously estimated population densities of these five ungulates at both local and landscape scales and explored causal factors underlying the variations in their densities in terms of different ecological and management factors.

Lead author and CWS scientist Samba Kumar said “Our results have both scientific and management implications. These are the first population ecology data and results gathered at such fine-grained scales on these vulnerable species which are under threat across their range in Asia.”

The study also highlights the importance of strict anti-hunting measures and regulation of human impacts on habitats which are far more important to recover these species than many of the costly and commonly employed habitat management practices. Kumar further said, “Our study also provides a scientifically robust decision-making framework to prioritize management actions to accomplish conservation goals.”

The results showed that population densities of focal species locally varied between 

0.2 and 5.1 / sq km for Gaur 

0.5 and 8.1 / sq km for Sambar 

0.9 and 39.8 / sq km for Chital 

0.1 and 0.7 / sq km for Muntjac  

0.1 and 1.1 / sq km for Wild Pig 

However, the above results were in response to varying environmental factors. The analytic methodology of Bayesian Hierarchical modelling used by the authors, generated more rigorous and nuanced results useful for conservation without involving any additional investment of resources compared to standard line transect sampling. 

Ullas Karanth, emeritus director, CWS added, “The approaches we developed and the results we generated have wide application for surveying large ungulate populations all over the world. In view of the fact that almost all the putative line transects surveys now being conducted across Asia, including those in India, lack rigor and generate unreliable results, there is ample scope for adopting our methods in the future. As tropical forest ungulates are under serious threat, I hope such adoption will be prioritized by the Government.” 

With a few notable exceptions, knowledge of population ecology of large, mobile animals is very limited, says James Nichols, University of Florida. “This is primarily because of the difficulty of studying such animals at relevant spatial scales. The study reported in this book is exceptional in being well-planned, well-executed via an enormous, supervised field effort, and well-analysed using state-of-the-art data-analytic approaches. As a result, the study provides strong inferences about the spatial ecology and conservation of the focal ungulates and provides a model for the large-scale study of mobile animal populations.”

The scientific monograph titled, Spatial Dynamics and Ecology of Large Ungulate Populations in Tropical Forests of India’ is authored by N Samba Kumar, K. Ullas Karanth (Centre for Wildlife Studies (CWS), Bengaluru), James D Nichols (University of Florida, USA), Srinivas Vaidyanathan (Foundation for Ecological Research, Advocacy and Learning, Pondicherry), Beth Gardner (University of Washington, USA) and Jagdish Krishnaswamy (Ashoka Trust for Research in Ecology and the Environment).