Ecological Informatics 69 (2022) 101639 Available online 3 April 2022 1574-9541/© 2022 Elsevier B.V. All rights reserved. Evaluation of Gangetic dolphin habitat suitability under hydroclimatic changes using a coupled hydrological-hydrodynamic approach Ashutosh Sharma a, * , Anupal Baruah b , Nikunj Mangukiya a , Gilbert Hinge c , Biswadeep Bharali d a Department of Hydrology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India b North Eastern Space Application Centre (NESAC), Department of Space, Government of India, Umiam 793103, Meghalaya, India c Department of Civil and Environmental Engineering, United Arab Emirates University, P.O. Box 15551, Al Ain, United Arab Emirates d Department of Civil Engineering, Assam Downtown University, Guwahati 781026, Assam, India A R T I C L E INFO Keywords: Climate change Eco-hydraulic modeling Hydrological model Habitat simulation Weighted usable area ABSTRACT The aquatic ecosystems are an integral part of the global environment and play a critical role in hydrogeological processes in the rivers. In recent decades, the external stressors on the aquatic species have signifcantly increased due to hydrologic alterations, human activities, and anthropogenic changes to their natural habitat. Global climate change has led to rivers' hydrological fow regime shifts, leading to unsuitable habitat conditions. It is, therefore, crucial to assess the potential implications of climate change on habitat suitability to ensure the long-term sustainability of freshwater species. In this direction, we investigated the association between en- dangered Gangetic dolphin populations and climate-driven hydrologic fow regime alterations in the Kulsi river, India. We developed a coupled eco-hydraulic framework comprising hydrological and hydrodynamic modeling to study the impact of past and projected climate change scenarios on the habitat suitability of target species. The framework was tested on a 15-km stretch of the Kulsi River, where the dolphin population has signifcantly declined in recent years. The temporal changes in the Weighted Usable Area (WUA) were analyzed using fow parameters and habitat suitability curves. Our fndings suggest that the dolphin population decline coincided with a decrease in WUA, indicating a strong association between fow regimes and habitat suitability. Under climate change scenarios, multi-model climate projections and hydrological-hydrodynamic simulations show a rising trend in precipitation and streamfow in the basin, with substantial uncertainty. Higher fow depth and velocity would enhance WUA (habitat suitability). Still, the proposed river development projects in upstream regions could pose a serious threat to fragile dolphin communities by changing the seasonal fow patterns. The fndings of this study can be included in conservation action plans and fow regulations strategies in upstream projects to ensure the long-term survival of endangered species. Symbols and Abbreviations CSI Composite Suitability Index GCM General Circulation Model H Water surface elevation (m) HRUs Hydrologic Response Units HSC Habitat Suitability Curves HSI Habitat Suitability Index RCP Representative Concentration Pathway SRTM Shuttle Radar Topographic Mission SWAT Soil and Water Assessment Tool Tmax Daily maximum temperature Tmin Daily minimum temperature WUA Weighted Usable Area (continued on next column) (continued ) ET Evapotranspiration (mm) P Percolated water (mm) Q Surface Runoff (mm) QR Return fow R Rainfall/Precipitation (mm) SW 0 Initial soil water content (mm) SW t Final soil water content (mm) 1. Introduction In recent decades, climate change has received considerable * Corresponding author. E-mail address: ashutosh.sharma@hy.iitr.ac.in (A. Sharma). Contents lists available at ScienceDirect Ecological Informatics journal homepage: www.elsevier.com/locate/ecolinf https://doi.org/10.1016/j.ecoinf.2022.101639 Received 24 January 2022; Received in revised form 29 March 2022; Accepted 30 March 2022