Occurrence and variability of River Habitat Survey features across Europe and the consequences for data collection and evaluation (original) (raw)
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The European REFORM Project for Hydromorphological Quality in River Basin Management
IntechOpen eBooks, 2024
The Water Framework Directive commits European Union member states to achieve good ecological and chemical status of all water bodies. As hydromorphology is a key factor for ecological status, a consortium of 26 partners from 15 countries studied the role of hydromorphological pressures and measures in the REFORM project. Its main objective was to answer the question: How to make river restoration successful? The project developed guidance for this by structuring the information along the different stages of restoration projects and river basin management plans, posing a logical sequence of questions: How does my river work? What's wrong? How to improve? Things can be wrong for ecological status as a result of morphological alterations. These alterations form pressures that can be countered or mitigated by measures that improve sedimentological and morphological features. We present two specific results of REFORM that focus on river morphology. First, we provide an overview of methods to assess morphological quality and diagnose alteration. Second, we present systematic cause-effect relationships for restoration measures.
2011
Adapting and adopting River Habitat Survey: Problems and solutions for fluvial hydromorphological assessment in Portugal The Water Framework Directive (WFD), which established the use of hydromorphological quality elements to assess the ecological status of water bodies, has influenced the purpose and content of several European methods for characterizing physical structure and assessing habitat quality in rivers. The River Habitat Survey (RHS) is a WFD compliant method developed in the UK and follows rapid and simple survey procedures using a standardised approach to characterize the physical habitat and evaluate hydromorphological quality. In Portugal, RHS was adopted for WFD purposes due to its successful long term application across the UK and other European countries. Even so, an effort was made to adapt the RHS to Portuguese regional and river characteristics, in order to accurately record habitat features, assess habitat quality and comply with legal requirements. This paper describes the constraints, adaptations, state of the art and way forward for a successful RHS implementation in Portugal. Constraints concerning the application of RHS to Mediterranean rivers are strongly related to natural hydromorphological processes, namely annual and inter-annual flow variability, which is a potential source of covariance with anthropogenic pressures. This leads to difficulties in recognizing and accurately recording some RHS features. Adaptations to RHS were introduced for survey guidelines, recording procedures and improved definitions of habitat features. Additional modifications were prepared in different sections of RHS field form to reflect Portuguese river features and incorporate components required by the WFD.
Journal of Applied Ecology, 2006
1The need for sensitive biological measures of aquatic ecosystem integrity applicable at large spatial scales has been highlighted by the implementation of the European Water Framework Directive. Using fish communities as indicators of habitat quality in rivers, we developed a multi-metric index to test our capacity to (i) correctly model a variety of metrics based on assemblage structure and functions, and (ii) discriminate between the effects of natural vs. human-induced environmental variability at a continental scale.2Information was collected for 5252 sites distributed among 1843 European rivers. Data included variables on fish assemblage structure, local environmental variables, sampling strategy and a river basin classification based on native fish fauna similarities accounting for regional effects on local assemblage structure. Fifty-eight metrics reflecting different aspects of fish assemblage structure and function were selected from the available literature and tested for their potential to indicate habitat degradation.3To quantify possible deviation from a ‘reference condition’ for any given site, we first established and validated statistical models describing metric responses to natural environmental variability in the absence of any significant human disturbance. We considered that the residual distributions of these models described the response range of each metric, whatever the natural environmental variability. After testing the sensitivity of these residuals to a gradient of human disturbance, we finally selected 10 metrics that were combined to obtain a European fish assemblage index. We demonstrated that (i) when considering only minimally disturbed sites the index remains invariant, regardless of environmental variability, and (ii) the index shows a significant negative linear response to a gradient of human disturbance.4Synthesis and applications. In this reference condition modelling approach, by including a more complete description of environmental variability at both local and regional scales it was possible to develop a novel fish biotic index transferable between catchments at the European scale. The use of functional metrics based on biological attributes of species instead of metrics based on species themselves reduced the index sensitivity to the variability of fish fauna across different biogeographical areas.The need for sensitive biological measures of aquatic ecosystem integrity applicable at large spatial scales has been highlighted by the implementation of the European Water Framework Directive. Using fish communities as indicators of habitat quality in rivers, we developed a multi-metric index to test our capacity to (i) correctly model a variety of metrics based on assemblage structure and functions, and (ii) discriminate between the effects of natural vs. human-induced environmental variability at a continental scale.Information was collected for 5252 sites distributed among 1843 European rivers. Data included variables on fish assemblage structure, local environmental variables, sampling strategy and a river basin classification based on native fish fauna similarities accounting for regional effects on local assemblage structure. Fifty-eight metrics reflecting different aspects of fish assemblage structure and function were selected from the available literature and tested for their potential to indicate habitat degradation.To quantify possible deviation from a ‘reference condition’ for any given site, we first established and validated statistical models describing metric responses to natural environmental variability in the absence of any significant human disturbance. We considered that the residual distributions of these models described the response range of each metric, whatever the natural environmental variability. After testing the sensitivity of these residuals to a gradient of human disturbance, we finally selected 10 metrics that were combined to obtain a European fish assemblage index. We demonstrated that (i) when considering only minimally disturbed sites the index remains invariant, regardless of environmental variability, and (ii) the index shows a significant negative linear response to a gradient of human disturbance.Synthesis and applications. In this reference condition modelling approach, by including a more complete description of environmental variability at both local and regional scales it was possible to develop a novel fish biotic index transferable between catchments at the European scale. The use of functional metrics based on biological attributes of species instead of metrics based on species themselves reduced the index sensitivity to the variability of fish fauna across different biogeographical areas.
Science of The Total Environment, 2019
A large number of national types prevent cross country comparison of rivers and lakes. • Data on type descriptors was compiled to allow similarity analysis of national types. • Clusters of similar national types provided 20 broad river types and 15 broad lake types. • The ecological status is best in highland types and worst in lowland calcareous types. • Broad types facilitate nutrient targets comparison and revision of EUNIS freshwater habitats.