Ecosystem stressors are "out of the ordinary" natural and unnatural inputs to the system that disturb the controlling factors, structure, and processes in the ecosystem. Stressors produce potentially large-scale effects on the natural spatial and temporal dynamics of the system.

List of non-natural ecosystem stressors in the Columbia River system:

• Agriculture
• Diking
• Dredging
• Filling
• Flow regulation
• Logging
• Marinas and overwater structures
• Shoreline armoring
• Urbanization
• Wastewater discharges
• Water diversion

List of natural ecosystem stressors in the Columbia River system:

• Extreme climatic events
• Seismic activity
• Volcanic activity