Journal Article


Sreedhar VijayakrishnanM Ananda KumarVinod KumarG UmapathyAnindya Sinha
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Physiological stress responses in wild Asian elephants Elephas maximus in a human-dominated landscape in the Western Ghats, southern India

Increasing anthropogenic pressures on forests, especially in the tropical regions of the world, have restrictedseveral large mammalian species such as the Asian elephant to fragmented habitats within human-dominatedlandscapes. In this study, we assessed the effects of an anthropogenic landscape and its associated conflict withhumans on the physiological stress responses displayed by Asian elephants in the Anamalai Hills of the WesternGhats mountains in south India. We have quantified faecal glucocorticoid metabolite (FGM) concentrations infocal individual elephants within and across herds, inhabiting both anthropogenic and natural habitats, andevaluated their physiological responses to different socio-ecological situations between November 2013 andApril 2014. Physiological stress responses varied significantly among the tested elephant age- and sex categoriesbut not across different types of social organisation. Adults generally showed higher FGM concentrations, even inthe absence of stressors, than did any other age category. Males also appeared to have higher stress responsesthan did females. Although there was no significant variation in mean stress levels between elephants on theplateau in the absence of human interactions and those in adjacent, relatively undisturbed forest habitats, FGMconcentrations increased significantly for adult and subadult individuals as well as for calves following drives,during which elephants were driven off aggressively by people. Our study emphasises the general importance ofunderstanding individual variation in physiology and behaviour within a population of a seriously threatenedmammalian species, the Asian elephant, and specifically highlights the need for long-term monitoring of thestress physiology and behavioural responses of individual elephants across both human-dominated and naturallandscapes. Such studies would not only provide comprehensive insights into the adaptive biology of elephantsin changing ecological regimes but also aid in the development of effective management and conservationstrategies for endangered populations of the species.

General and Comparative Endocrinology