Linkages between flow regime, biota, and ecosystem processes: Implications for river restoration

Area of Science:

• Ecology
• Hydrology
• Environmental Science

Background:

• River ecosystems are vital for biodiversity and global biogeochemical cycles.
• Human activities, particularly altering streamflows, increasingly degrade these valuable fluvial ecosystems.
• Effective river restoration hinges on a mechanistic understanding of flow-regime impacts on biota and ecosystem functions.

Purpose of the Study:

• To review advances in hydroecology concerning flow-regime effects on river ecosystems.
• To synthesize current understanding of how spatiotemporal flow variation influences riverine communities and processes.
• To identify research priorities for advancing process-based river restoration.

Main Methods:

• Review of emerging advances in hydroecology.
• Synthesis of studies on flow-biota-ecosystem process interactions.
• Illustration with case studies from regulated rivers and urban streams.

Main Results:

• Spatiotemporal flow variation directly and indirectly controls river community composition, structure, and dynamics.
• Streamflows significantly influence key ecosystem processes like nutrient cycling, organic matter processing, and metabolism.
• Research on the nexus of flow, biota, and ecosystem processes is still in its early stages.

Conclusions:

• A deeper understanding of biological processes influencing and being influenced by stream ecosystems is developing.
• Further research is needed to address challenges in process-based river restoration.
• Prioritizing research at the flow-biota-ecosystem process nexus is essential for advancing restoration science.