Responses of river dolphins to flood induced natural river dynamics and human perturbations
Goal: Investigate how flood induced natural river course change modify the distribution of anthropogenic risks to river dolphins
Riverine species are adapted to natural changes in habitats caused by seasonal flood pulses. Abrupt river course changes following intense flooding events interact with and modify socially defined configurations of land and water management (e.g. protected area). Endangered aquatic species thus need to adaptively respond to resulting risk trade-offs after rapid transitions.
We investigated the responses of Ganges river dolphin to natural flood-induced habitat change and fisheries in Nepal using field data and long-term hydrological observation at the lower Karnali sub-basin in Nepal. The key highlights of our work are : 1) Natural river channel dynamics modify the distribution of anthropogenic risks to dolphins, 2) Irrigation demands reduce river depth to critical levels even in unregulated rivers of Nepal, 3) Fishing intensity negatively affects small river dolphin populations at low river depths, and 4) Highlights need to balance irrigation demands with ecological flows to conserve river dolphins.