Report on the Central Baltic River GIG Macrophyte Intercalibration Exercise June 2007
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Version 2 – July 9th, 2007 Report on the Central Baltic River GIG Macrophyte Intercalibration Exercise June 2007 Authors: Sebastian Birk University of Duisburg-Essen, DE Nigel Willby University of Stirling, UK Christian Chauvin CEMAGREF, FR Hugo Coops Delft Hydraulics, NL Luc Denys Research Institute for Nature and Forest, BE (FL) Daniel Galoux CRNFB, BE (WL) Agnieszka Kolada Institute of Environmental Protection, PL Karin Pall Systema, AT Isabel Pardo University of Vigo, ES Roelf Pot NL Doris Stelzer DE CBrivGIG Macrophyte Intercalibration Report Table of Contents 0 Executive Summary..................................................................................................4 1 Introduction...............................................................................................................6 2 National Assessment Methods .................................................................................7 2.1 Survey............................................................................................................................7 2.2 Abundance .....................................................................................................................7 2.3 Assessment and Classification.......................................................................................8 3 Common Intercalibration Types..............................................................................13 4 Data Basis ..............................................................................................................15 4.1 Common international macrophyte database (MaPHYTE-DB) ....................................15 4.2 International abundance scale .....................................................................................18 4.3 Common list of macrophyte taxa..................................................................................19 5 Intercalibration Option 2: Use of Common Metrics.................................................25 5.1 Introduction ..................................................................................................................25 5.2 Development of a common scoring system for European river plants based on sensitivity to nutrient enrichment ................................................................................25 5.3 International species response groups.........................................................................29 5.4 Use of response groups for visualisation and boundary setting ...................................32 5.5 IC Option 2 Analytical Procedure .................................................................................32 5.6 IC Option 2 Pilot Exercise ............................................................................................33 6 Intercalibration Option 3: Direct Comparison..........................................................41 6.1 Application of the CB lakes GIG approach...................................................................41 6.2 Application of class-by-class approach ........................................................................43 6.3 Joint evaluation of lowland datasets.............................................................................48 6.4 General points in relation to IC Option 3 ......................................................................48 7 Discussion ..............................................................................................................50 8 Literature ................................................................................................................53 Annex I: List of ITEM scoring taxa and (sub-)type specific response groups ......................55 Annex II: Towards Macrophytes IC in large rivers - First reflections (by Christian Chauvin)63 Annex III: Correction factor to apply Dutch method to single site data (by Roelf Pot) .........70 Annex IV: Intercalibration of water body metrics (by Hugo Coops) .....................................71 Annex V: References in macrophyte IC – Summary of current discussions........................79 2 CBrivGIG Macrophyte Intercalibration Report Abbreviations AIM Rivers Austrian Index for Macrophytes in Rivers AT Austria BE (FL) Belgium (Flanders) BE (WL) Belgium (Wallonia) BQE Biological Quality Element CBrivGIG Central Baltic rivers Geographical Intercalibration Group CZ Czech Republic DE Germany DK Denmark EQR Ecological Quality Ratio ES Spain FR France GM Good-Moderate Quality Class Boundary HG High-Good Quality Class Boundary IBMR Indice Biologique Macrophytique en Rivière IC Intercalibration ICM Intercalibration Common Metric IT Italy ITEM Index of Trophy for European Macrophytes ITEMcov ITEM based on international abundance scale translated into cover percentages LT Lithuania LU Luxemburg LV Latvia MIR Polish Macrophyte Index for Rivers MTR Mean Trophic Ranking NL Netherlands PL Poland R-C Abbreviation of Common Intercalibration Types of the CBrivGIG REF Reference Value RI German Reference Index RMNI British River Macrophyte Nutrient Index SE Sweden UK United Kingdom 3 0 Executive Summary 0 Executive Summary National macrophyte assessment methods • 7 countries and 8 regions (Austria, Belgium (FL), Belgium (WL), France, Germany, Great Britain, Netherlands, Poland) participate in the macrophyte intercalibration exercise for rivers. • National assessment methods are designed to deliver diverse information on stream ecosystems. The majority of schemes focuses on the assessment of nutrient enrichment (France, Great Britain, Poland, Wallonia, partly Austria). A list of indicator taxa graded by their sensitivity to nutrient enrichment forms the principal component of this approach. • The Dutch, Flemish and German macrophyte assessment methods are oriented towards the indication of non-specific anthropogenic disturbance. Besides compositional measures these schemes consider additional metrics such as richness and abundance of growth forms, or taxa richness and dominance. Intercalibration typology for river macrophytes • To adapt the intercalibration typology to the specific requirements of river macrophyte assessment, lowland types were further sub-divided based on the descriptors altitude, alkalinity and geology. Common intercalibration database • The common international database established for macrophyte intercalibration currently comprises approx. 1400 macrophyte survey data from about 1200 river sites in 16 countries. Data originate from national monitoring programmes or scientific projects. International abundance scale • To allow for common analysis of data national abundance values were assigned to one of five international abundance classes using expert judgement. This harmonisation was enabled by agreeing on common verbal descriptions of taxon abundances that surveyors come across in the field. Common list of macrophyte taxa • A common macrophyte list covering the operational taxa lists of all countries involved in intercalibration was built. Principal objective was to have a common basis for the selection of indicator taxa available as a reference for the comparison of national survey data and assessment methods. Analysis using IC Option 2 • Main focus of the intercalibration analyses was the development and application of Intercalibration Common Metrics following the approaches of the invertebrate and phytobenthos intercalibration exercises. • Intercalibration basics were established by setting up international macrophyte indicator scores related to nutrient pressure, compiling a list of type-specific international species response groups, and developing a common intercalibration metric to compare class boundaries of national methods assessing eutrophication. • Preliminary analyses of boundary comparison between national methods for IC types R- C2, R-C3 and R-C4.x.2 are presented in this report. Instruments for the validation of 4 0 Executive Summary harmonised boundary setting are outlined (biological community aspects, pressure-impact relations). Application of IC Option 3 • In an attempt to circumvent difficulties in applying Option 2 due to weak correlations between some national classifications and the common metric IC Option 3 was applied to three common river types. • Most of the observed deviation between national classifications seemed to be caused by misinterpretation of data because of incompleteness for the national assessment method of other countries. Future adjustments of the analysis will most probably improve intercalibration according to Option 3. • Option 3 will not produce intercalibration if national methods are measuring different aspects of the Biological Quality Element (BQE) or reflecting different pressures to which the BQE responds. • In comparison to Option 2, it appears that countries falling outside the bands of acceptability in Option 3 must make quite substantial changes to their classifications in order to harmonise (based on the thresholds currently set). Conclusions and outlook • At the moment intercalibration tools are available to compare schemes focussing on nutrient pressure, or to intercalibrate at common types in which eutrophication gradients play the major role (mountain rivers). • Joint evaluation of lowland datasets within the CBrivGIG intercalibration exercise revealed general agreement about type-specific biological communities at high status. This common view was not always reproduced by the classification results of national schemes. • This suggests that a harmonisation of assessment concepts will facilitate the