Abstract: The massive dietary requirement of megaherbivores shapes their ecology, behaviour, and their functional roles such as herbivory, seed dispersal, disturbance, etc. which influence ecosystem processes. While their generalist diet allows feeding on low-quality food, the competition-induced constraints on group size and a tight time-budget dominated by foraging-related activities poses challenges to the maintenance of social bonds. In this talk, He will first present his past research on the socioecology of female Asian elephants in Kabini, southern India. Using field observations, he examined some hypotheses from the socioecological theory that links resource distribution with competitive relationships in female-bonded groups. Specifically, he explores whether patchy food intensifies contest competition and results in strongly differentiated dominance structure. He found the lack of a clear link between resource distribution, contest competition and dominance. Further, inter-population comparison suggests that female Asian elephant societies have a more egalitarian structure than the more differentiated relationships in African savannah elephants who face greater predation risk and environmental unpredictability. These findings offer a mixed support to socioecological theory.
Secondly, He will present his proposal to study the functional roles of megaherbivores in the ecosystems of India and the ecological consequences of their extinctions. Using classical herbivore-exclusion experiments along a gradient of body size, his aim is to understand how the decline in megaherbivore diversity affects vegetation dynamics. Further, he will investigate how megaherbivore functional diversity is linked with vegetation structure/composition at coarse scales. Mapping the historical distribution of megaherbivores will further inform about the ecological consequences of their local extinctions.
Bio: Dr. Hansraj is currently a SERB National Postdoctoral Fellow at NCBS, Bengaluru, and his primary research interests are in animal behaviour, ecology, and biodiversity in a changing world. Specifically, He is interested in the socioecology of group-living animals, the functional roles of megaherbivores in shaping vegetation and ecosystems, and vegetation monitoring using remote sensing tools. In his Ph.D. research on the socioecology of Asian elephants in Kabini, southern India, he investigated the link between food distribution, within- and between-clan contest competition, and feeding consequences of dominance in female elephant societies. His plan is to expand to cross- taxon examinations to further understand the causes and consequences of group-living in animals. Currently, he is pursuing my interest in the roles of megaherbivores in shaping vegetation dynamics and ecosystem processes. His current postdoc project is on examining the role of elephants in seed dispersal and plant community assembly. His other ongoing project involves mapping the long-term invasion patterns of woody shrubs and their impact on native vegetation and herbivore food plants, in Nagarahole, southern India. In future, He wants to investigate how local extinctions of megaherbivores and the consequent decline in their functional diversity influences vegetation in different ecosystems of India. This inter-disciplinary work will involve classical herbivore-exclusion experiments, long-term vegetation monitoring, remote sensing analyses, and analysis of historical and palaeoecological records.