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Martin Søndergaard

Macrophyte assessment in European lakes: Diverse approaches but convergent views of ‘good’ ecological status

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DOI

  • Sandra Poikane, European Commission Joint Research Centre, Ispra
  • ,
  • Rob Portielje, Rijkswaterstaat
  • ,
  • Luc Denys, Research Institute for Nature and Forest, Brussels
  • ,
  • Didzis Elferts, University of Latvia, Latvia
  • ,
  • Martyn Kelly, Bowburn Consultancy
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  • Agnieszka Kolada, Department of Freshwater Protection
  • ,
  • Helle Mäemets, Estonian University of Life Sciences
  • ,
  • Geoff Phillips, University of Stirling
  • ,
  • Martin Søndergaard
  • Nigel Willby, University of Stirling
  • ,
  • Marcel S. van den Berg, Rijkswaterstaat

The European Water Framework Directive has been adopted by Member States to assess and manage the ecological integrity of surface waters. Specific challenges include harmonizing diverse assessment systems across Europe, linking ecological assessment to restoration measures and reaching a common view on ‘good’ ecological status. In this study, nine national macrophyte-based approaches for assessing ecological status were compared and harmonized, using a large dataset of 539 European lakes. A macrophyte common metric, representing the average standardized view of each lake by all countries, was used to compare national methods. This was also shown to reflect the total phosphorus (r2 = 0.32), total nitrogen (r2 = 0.22) as well as chlorophyll-a (r2 = 0.35–0.38) gradients, providing a link between ecological data, stressors and management decisions. Despite differing assessment approaches and initial differences in classification, a consensus was reached on how type-specific macrophyte assemblages change across the ecological status gradient and where ecological status boundaries should lie. A marked decline in submerged vegetation, especially Charophyta (characterizing ‘good’ status), and an increase in abundance of free-floating plants (characterizing ‘less than good’ status) were the most significant changes along the ecological status gradient. Macrophyte communities of ‘good’ status lakes were diverse with many charophytes and several Potamogeton species. A large number of taxa occurred across the entire gradient, but only a minority dominated at ‘less than good’ status, including filamentous algae, lemnids, nymphaeids, and several elodeids (e.g., Zannichellia palustris and Elodea nuttallii). Our findings establish a ‘guiding image’ of the macrophyte community at ‘good’ ecological status in hard-water lakes of the Central-Baltic region of Europe.

Original languageEnglish
JournalEcological Indicators
Volume94
Pages (from-to)185-197
Number of pages13
ISSN1470-160X
DOIs
Publication statusPublished - 1 Nov 2018

    Research areas

  • Aquatic macrophytes, Ecological status, Eutrophication, Indicator species, Nutrients, Phosphorus, Species richness, Water Framework Directive

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