6 research outputs found
Ecological threshold responses in European Lakes and their applicability for the Water Framework Directive (WFD)implementation: synthesis of lakes results from the REBECCA project
Abstract The objective of this synthesis is to
present the key messages and draw the main conclusions
from the work on lakes in the REBECCA
project, pointing out their links to theoretical ecology
and their applicability for the WFD implementation.
Type-specific results were obtained from analyses of
large pan-European datasets for phytoplankton, macrophytes,
macroinvertebrates and fish, and indicators
and relationships showing the impact of eutrophication
or acidification on these biological elements
were constructed. The thresholds identified in many
of the response curves are well suited for setting
ecological status class boundaries and can be applied
in the intercalibration of classification systems. Good
indicators for phytoplankton (chrysophytes, cyanobacteria)
and macrophytes (isoetids and charaphytes)
responses to eutrophication were identified, and the
level of eutrophication pressure needed to reach the
thresholds for these indicators was quantified. Several
existing metrics developed for macrophytes had low
comparability and need further harmonisation to be
useful for intercalibration of classification systems.
For macroinvertebrates, a number of metrics developed
for rivers turned out to be less useful to describe
lake responses to eutrophication and acidification,
whereas other species based indicators were more promising. All the biological elements showed different responses in different lake types according to alkalinity and humic substances, and also partly
according to depth. Better harmonisation of monitoring
methods is needed to achieve better precision in
the dose–response curves. Future research should
include impacts of hydromorphological pressures and
climate change, as well as predictions of timelags
involved in responses to reduction of pressures