Improved river continuity facilitates fishes' abilities to track future environmental changes

Area of Science:

• River ecology
• Conservation biology
• Environmental management

Background:

• Anthropogenic barriers (e.g., weirs, dams) significantly impact river ecosystems and fish migration.
• Restoring longitudinal connectivity is crucial for fish movement and adaptation to environmental changes.
• Identifying key barriers for specific fish species is essential for effective river management.

Purpose of the Study:

• To evaluate the impact of river barriers on the dispersal of 17 native fish species in the River Elbe.
• To assess how barriers affect fish ability to track climate- and land use-induced habitat shifts.
• To compare the effectiveness of current, planned, and ideal river connectivity scenarios.

Main Methods:

• Application of species distribution models.
• Utilizing the GIS-based fish dispersal model FIDIMO.
• Analysis of three longitudinal connectivity scenarios: current, planned (2021), and full connectivity.

Main Results:

• Barriers restricted the movement of an average of two modeled fish species, hindering their adaptation to future habitat shifts.
• The negative impact of barriers on fish dispersal increased downstream in the River Elbe.
• River management plans appear to target the most relevant barriers for the studied species and future environmental changes.

Conclusions:

• River management strategies should prioritize species-specific dispersal abilities and habitat availability.
• Effective barrier prioritization requires understanding the spatial distribution of fish populations and suitable habitats.
• Integrating ecological data into barrier management is vital for successful river restoration and fish conservation.