As it is beneficial to understand where an ecosystem was prior to stressors, there are common symptoms in which signal ecosystem degradation; they have been identified from reoccurring stressor impacts and described with the ecosystem distress syndrome concept.
Degradative symptoms characterise many ecosystems that are experiencing multiple stressors. \citet{Rapport_1992} claims that aquatic ecosystem distress syndrome can include some or most of the symptoms listed: alteration in biotic community structure to favor smaller forms, reduced species diversity, increased dominance by 'r' selected species, increased dominance by exotic species, shortened food-chain length, increased disease prevalence, and reduced population stability. \citep{Rapport_1992a}