European surface waters are impacted by multiple environmental stressorsAn environmental pressure that poses adverse impact on aquatic ecosystems and water uses which adversely affect their ecological qualityDistance of biota and ecological conditions to undisturbed references. Since 2000, the Water Framework Directive requires to improve the ecological status of all surface waters that do not meet the “good ecological status”.
Therefore, improved assessment methods to identify degree and causes of degradation, and methods to design recovery schemes and to predict their success are required.
Many countries still lack sufficient assessment methods, particularly for certain freshwater ecosystem types (e.g. lakes) and organism groups (e.g. fish).
Numerous projects to restore degraded water bodies have been started; however, knowledge on their effects on freshwater organisms is still incomplete.