Key messages
A lot of questions frequently arise in the daily business of river basin and water management. The answers are not trivial and have been subject to the large-scale integrated project WISER.
This section summerizes clearly key messages, evidences, implications and further information in a step-by-step overview for different water categories.
Review of data and methods
- Intercalibration is a fundamental prerequisite to compare the results of hundreds of bio-indicator systems in Europe
- The WISER Central Database is of great value for future research
Lake assessment
- The reliable assessment of the impact of different lake stressors requires the use of different Biological Quality Elements
Transitional and coastal water assessment
- Marine phytoplankton revealed a high level of spatial and annual variability across Europe
- A new phytoplankton size spectra index (SSI) has been developed for the assessment of transitional waters in Europe
- Marine macroalgae are useful ecological quality indicators under the WFD monitoring programs
- Benthic invertebrates respond consistently to human pressure gradients across transitional and coastal waters
- Zoobenthos species traits are useful and reliable for the assessment of transitional water ecosystems
- Fish indicators respond consistently to human pressure gradients across transitional waters
- Setting adequate reference conditions in assessing benthic quality is one of the most important tasks
- Defining type-specific reference conditions for benthic macroinvertebrates in Mediterranean lagoons is not trivial, but required to minimize misclassification
- Defining ecological potential in transitional waters is challenging
Uncertainty in water body assessment
- WISER improved the knowledge on the sources of uncertainty in ecological status classification
- Uncertainty may vary between different metrics calculated for the same BQE
- The WISER Bioassessment Uncertainty Guidance Software (WISERBUGS) helps water managers quantify the sampling uncertainty and confidence of water body ecological status classification
- Spatial heterogeneity is the main source of uncertainty when classifying ecological status using marine macrophyte indices
- A smart sampling design may help reduce the uncertainty in lake assessment
- Uncertainty levels associated with metric variability in multi-metric fish indices can be managed to increase the confidence in ecological status class assignment
River management
- Riverine assemblages respond differently to individual stressors and stress levels
- Environmental stressors act hierarchically
- Catchment and riparian land use control local habitat conditions
- Restoration is more likely to be successful, if upstream physical habitat degradation and land use impacts are low
- Local restoration is often unsuccessful
- River Basin Management Plans insufficiently account for research and monitoring demands
- Climate change alters fish assemblage structure and function distribution in Europe
Lake management
- Climate warming causes profound changes in lake fish assemblages
- Include zooplankton as a BQE in assessment of lake ecological status, please
- Models can guide lake restoration if following good modelling practise — results from two case studies
- Impacts of climate change and restoration on ecological status class: a management-oriented modelling approach
- A tool may help estimate the effects of nutrient load reduction under a variety of climate scenarios
- Lake sediments provide insight into the history of the conditions of individual lakes and, hence may assist the definition of reference conditions
Transitional and coastal water management
- Benthic communities become more vulnerable to hypoxia with warming
- Hydrogen sulphide exacerbates effects of hypoxia
- Phytoplankton biomass yield relative to nutrients have doubled
- Hypoxia makes ecosystem recovery more difficult
- Recovery of estuarine and coastal ecosystems takes decades
- The loss of benthic vegetation sustains a turbid regime
- Ecological regime shifts affect seagrass pressure-indicator responses and delay recovery
Synthesis and integration
- The 'one-out all-out' principle for combining multiple BQEs into an integrated classification must be applied with caution
- Restoration can only become successful when all pressures are tackled simultaneously
- Recovery needs time, long time
- Monitoring of restoration needs a before-after-control-impact design to learn by doing