Macrophytes (workpackage 3.2)
The main objectives of this workpackage are to:
- validate and supplement lake macrophyte metrics based on species composition, abundance and/or community structure for assessment of impacts of eutrophication,
- develop relevant metrics to assess response of lake macrophytes to water level fluctuations, explore the use of palaeoecological approaches (plant macrofossil records) to define reference conditions and to assess ecological status for selected lake types,
- quantify the main sources of uncertainty in tested and selected macrophyte metrics,
- test combination rules for single metrics to either one multimetric or to one final assessment result for benthic macroflora (element-level assessment) and
- evaluate the potential and limitations for using aerial photography as a low-cost monitoring method for macrophyte assessments.
Altogether, existing macrophyte data from almost 2000 lakes in 16 European countries have been collated for the development of macrophyte metrics and validation. The data has been gathered in close cooperation with macrophyte experts from various Geographical Intercalibration Groups (GIGs). A field survey in summer 2009 was carried out in 28 lakes across Europe to quantify uncertainty in macrophyte metrics related to sampling design and methods, and to identification. At each lake, macrophytes were sampled from six locations with three replicates each per location. The transect methods and further methodological details have been described in deliverable D3.2-1. In addition, hydromorphological data has been recorded using the Lake Habitat Survey (LHS) rapid protocol. Biological and environmental data has been compiled in a workpackage database that is part of the WISER central database.
In spring 2009 the overview and comparison of existing macrophyte survey methods used in European countries have been completed and published (deliverable 3.2-1). Based on this overview, a harmonised sampling procedure including a common sampling protocol has been elaborated. The common macrophyte taxa list for European lakes including synonyms and common taxon IDs (codes) has been compiled. The list comprises of a total of approximately 1,100 taxa (species and subspecies level) and, in addition to aquatic vascular plants, includes also macroscopic algae (Characeans), bryophytes, ferns and semi-aquatic helophytes. This data is available online: www.freshwaterecology.info.
All data is being used to derive and test macrophyte metrics for their sensitivity and precision against two major groups of pressures in different lake types and geographical regions (GIGs): eutrophication and water level fluctuations. The metrics tested cover qualitative (taxonomic composition), as well as quantitative measurements (mainly maximum depth of colonisation and % cover). This work plan describes the use of quantitative metric, mainly maximum depth of colonization.
Relevance for end-users
The development of common metrics is being carried out in close collaboration with Geographical Intercalibration Groups (GIGs) and should be complete in autumn 2010 to support the intercalibration process. This will provide a common measure and facilitate the comparison of various national macrophyte method's assessment results in EU Member States. The overview of existing macrophyte survey methods and the common sampling procedure elaborated for the WISER lake macrophyte field campaign can be used as a background when elaborating new methods in those countries that still lack standards for macrophyte sampling. The common lake macrophyte taxa list provides a tentative standard for lake monitoring at the European scale. The work on uncertainty will provide an information about the robustness and precision of selected macrophyte metrics and will allow estimate the confidence of the results provided by the assessment methods to be demonstrated in the River Basin Management Plans, as required by WFD.
Dr Agnieszka Kolada, Institute of Environmental Protection, PL