Assessing ecological quality of shallow lakes: Does knowledge of transparency suffice?
Author
Summary, in English
The European Water Framework Directive (WFD) requires that all aquatic ecosystems in their member states
should reach ‘good’ ecological quality by 2015. To assess ecological quality, the WFD requires the definition of
reference conditions using biological, physical and chemical indicators and the assignment of each water body to one
of five quality classes using these indicators. Elaborate assessment schemes using large sets of variables are now being
developed. Here we address the question whether all this is really needed and what the simplest assessment approach
would be for the case of shallow lakes. We explore the relationships between the quality class assigned to a lake by
experts in shallow lake ecology and a rich set of biological, physical, and chemical data. Multinomial logistic regression
analyses were carried out based on data from 86 shallow lakes throughout Europe that were sampled in 2000 and/or
2001. Ecological quality of shallow lakes judged by experts was strongly correlated to physical and chemical variables
associated with light regime and nutrients and much less to biological variables.
Our regression model showed that ecological quality of this set of shallow lakes judged by experts could be predicted
quite well from water transparency expressed as Secchi depth and that other variables did not contribute to it significantly. According to the WFD, lakes should at least have a ‘good’ ecological quality. Quality judged by experts
and predicted quality were similar for 78% of the lakes with respect to meeting this standard. As a cautionary note we
stress that Secchi depth alone will be a less useful indicator if effects of stressors other than eutrophication (e.g. lake
acidification and toxic pollution) are to be considered.
should reach ‘good’ ecological quality by 2015. To assess ecological quality, the WFD requires the definition of
reference conditions using biological, physical and chemical indicators and the assignment of each water body to one
of five quality classes using these indicators. Elaborate assessment schemes using large sets of variables are now being
developed. Here we address the question whether all this is really needed and what the simplest assessment approach
would be for the case of shallow lakes. We explore the relationships between the quality class assigned to a lake by
experts in shallow lake ecology and a rich set of biological, physical, and chemical data. Multinomial logistic regression
analyses were carried out based on data from 86 shallow lakes throughout Europe that were sampled in 2000 and/or
2001. Ecological quality of shallow lakes judged by experts was strongly correlated to physical and chemical variables
associated with light regime and nutrients and much less to biological variables.
Our regression model showed that ecological quality of this set of shallow lakes judged by experts could be predicted
quite well from water transparency expressed as Secchi depth and that other variables did not contribute to it significantly. According to the WFD, lakes should at least have a ‘good’ ecological quality. Quality judged by experts
and predicted quality were similar for 78% of the lakes with respect to meeting this standard. As a cautionary note we
stress that Secchi depth alone will be a less useful indicator if effects of stressors other than eutrophication (e.g. lake
acidification and toxic pollution) are to be considered.
Department/s
Publishing year
2009
Language
English
Pages
89-96
Publication/Series
Basic and Applied Ecology
Volume
10
Links
Document type
Journal article
Publisher
Elsevier
Topic
- Ecology
Keywords
- Restoration
- Prediction
- Multinomial logistic regression
- Modelling
- Lake management
- Expert judgement
- ECOFRAME
- Eutrophication
- Secchi depth
- Water framework directive
Status
Published
Research group
- Aquatic Ecology
ISBN/ISSN/Other
- ISSN: 1618-0089