Specificity | Biological response is specific to the stressor of interest and not to other environmental stressors |
Monotonicity | The magnitude of the biological response should reflect the intensity and duration of the stressor of interest |
Variability | Biological responses should be consistent at a range of spatial and temporal scales. Ideally, there should be low background variability although a change in variance can itself be used as an indicator of an impact |
Practicality | Measurements of biological responses should be cost effective, easy to measure, non-destructive and observer independent |
Relevance | Biological response should be ecologically relevant and important in public perception to assist communication |