Interbasin water transfer, riverine connectivity, and spatial controls on fish biodiversity

Area of Science:

• Ecology
• Conservation Biology
• Environmental Science

Background:

• Inter-basin water transfer (IBWT) projects are proposed to address water scarcity, exacerbated by population growth and climate change.
• Assessing IBWT impacts on freshwater fish is challenging due to limited biodiversity data.
• Habitat network connectivity is crucial for species biogeography and managing IBWT ecological effects.

Purpose of the Study:

• To evaluate the impact of inter-basin water transfer projects on freshwater fish biodiversity in peninsular India.
• To explore strategies for mitigating the ecological consequences of IBWT implementation.
• To understand the relationship between riverine network geometry and fish biodiversity.

Main Methods:

• Utilized empirical data on freshwater fish biodiversity in peninsular Indian rivers.
• Modeled spatial changes resulting from an archetypal IBWT project.
• Assessed two step-wise implementation strategies for 11 canals, considering economic and ecological factors.

Main Results:

• IBWT projects are projected to decrease overall freshwater fish biodiversity.
• Local species richness patterns will be altered, favoring widespread species.
• Increased inter-basin similarity in fish communities will lead to reduced biodiversity.
• The sequence of canal addition significantly influences ecological impacts.

Conclusions:

• Ecological impacts of IBWT can be minimized by strategic, sequential canal implementation.
• Simultaneous construction of all canals negates the benefits of strategic sequencing.
• Understanding river network geometry is key to assessing IBWT impacts and balancing human and ecosystem needs for water.