Eurasian beaver activity increases water storage, attenuates flow and mitigates diffuse pollution from...

Area of Science:

• Ecology
• Environmental Science
• Hydrology

Background:

• Beavers are keystone species that engineer ecosystems, significantly impacting water resources.
• Previous studies focused on North American beavers in different environments.
• European agricultural landscapes face water management challenges.

Purpose of the Study:

• To assess the impact of Eurasian beavers (Castor fiber) on water storage, flow regimes, and water quality in a UK agricultural catchment.
• To understand beaver ecosystem engineering effects in a European context.

Main Methods:

• Introduction of two Eurasian beavers to a first-order tributary draining grassland.
• Monitoring of water storage, flow (peak discharge, total discharge, lag times), and water quality (suspended sediment, nitrogen, phosphate, dissolved organic carbon).
• Analysis of data during storm events and continuous monitoring of water entering and leaving the site.

Main Results:

• Beaver dams (13) increased water storage by approximately 1000m³.
• Significant flow attenuation observed: peak discharges reduced by 30%, total discharges by 34%, and lag times increased by 29%.
• Reduced downstream concentrations of suspended sediment (average 112 to 39 mgl⁻¹), nitrogen, and phosphate.
• Increased downstream dissolved organic carbon concentrations and loads.
• Creation of a diverse wetland environment with reduced hydrological connectivity.

Conclusions:

• Eurasian beaver activity significantly alters hydrological processes and water quality in agricultural catchments.
• Beaver reintroduction offers nature-based solutions for water resource management challenges in European agricultural landscapes.
• The creation of beaver wetlands effectively reduces diffuse pollution and modifies flow regimes.