Differential response of multiple stream ecosystem processes to basin- and reach-scale drivers

Area of Science:

• * Ecological sciences
• * Environmental science
• * Hydrology

Background:

• * Stream ecosystems are sensitive to surrounding environmental conditions and anthropogenic pressures.
• * Ecosystem functioning in streams is influenced by complex interactions between natural dynamics and human-induced changes.
• * Assessing multiple ecosystem processes is key to understanding overall stream health.

Purpose of the Study:

• * To identify natural and anthropogenic drivers of multiple stream ecosystem processes at a regional scale.
• * To analyze the influence of basin- and reach-scale factors on nutrient uptake, biomass accrual, decomposition, and ecosystem metabolism.
• * To evaluate the impact of urban land-use on stream ecosystem functioning.

Main Methods:

• * Examined 38 natural and anthropogenic variables across 63 stream reaches.
• * Employed structural equation modeling to determine cascading effects of drivers.
• * Focused on the Gipuzkoa region (northern Iberian Peninsula).

Main Results:

• * Significant spatial variability observed in stream ecosystem processes, with differing responses to environmental factors.
• * Urban land-use identified as a primary basin-scale driver impacting stream functions.
• * Nutrient uptake primarily driven by water nutrient concentrations; other processes showed more complex relationships.

Conclusions:

• * Urban areas exert a disproportionately large impact on stream ecosystem processes and services.
• * Measuring multiple ecosystem functions simultaneously provides a comprehensive assessment of river status.
• * Findings underscore the need to consider land-use impacts for effective stream management and conservation.