Table 1 Summary of stressors and the respective scales on which they operate
Scale | Specific stressor |
|---|---|
Time-scale stressors | Time |
Large-scale stressors (catchment scale) | Scope of restoration measure |
Massive input of (contaminated) fine sediments | |
Acidification and bioavailability of metals | |
Increasing salinization | |
Iron hydroxide deposition | |
Eutrophication by nitrogen release originating from organic compounds | |
General chemical contamination | |
Medium-scale stressors (reach scale) | Altered flow regime, bedload dynamics and depth variance |
Weak self-dynamic development | |
Low lateral connectivity | |
Absence of riparian strips | |
Intensive river maintenance measures | |
Inappropriate shading and temperature regime | |
Insufficient longitudinal continuity | |
Absence of source populations | |
Biotic interactions | |
Small-scale stressors (local scale) | Inappropriate design of restoration measures |
Insufficient substrate diversity | |
Structure of watercourse |