Bio-fencing as Promising Solution for Human-Elephant Conflict (HEC): Responses of Elephants and Underlying Leaf Chemistry of Polyalthia longifolia

Abstract

Bio-fencing could be used as an effective tool for human-elephant conflict mitigation, yet the plant species currently used need to be more viable. Polyalthia longifolia is reported to be having antifeedant properties against herbivores and is repellent to them. Accordingly, two cases were studied to evaluate the antifeedant and repellency nature of the plant by offering P. longifolia; (1) to wild elephants in 03 locations in Mahaweli System D, Sri Lanka and (2) to tamed elephants of 03 age groups. The preference of tamed elephants were further evaluated giving leafy materials; coconut, fishtail palm, grass mixture, and P. longifolia simultaneously. As a necessary consequence, this study was intended to (3) assess the relative levels of moisture, ash, crude fat, crude fiber, crude protein and (4) organic volatile compounds responsible for the odor of offered plant materials using a PEN3 electronic nose, and to (5) determine the relationship between leaf proximate parameters with palatability responses and (6) organic volatile compounds. Results showed that the wild elephants prevent their movement through their routes by placing bunches of P. longifolia leaf branches. Tamed elephants showed abnormal responses against P. longifolia particularly movements of their body compared to the rest of feeding materials implying that the leaves of P. longifolia are antifeedant and repellant to them, suggesting the greater potential as an effective bio-fence against elephants. However, estimated differences in leaf proximate parameters and relative levels of organic volatile compounds did not reveal the witnessed contrasting repellency of P. longifolia.