Jürgen Böhmer Group experts: Angelo Solimini (IT; Wiser; Lead),

1. Results of AL-GIG Lake Benthic Fauna Intercalibration ECOSTAT, Ispra, 21 March 2012 JürgenBöhmer Group experts: Angelo Solimini (IT; Wiser; Lead), Christine Argiller (FR), Angela Boggero (IT), Jürgen Böhmer (DE), Muriel Gevrey (FR), Gorazd Urbanic (SI), Georg Wolfram (AT)

2. Methods * Methods finalised too late for successful intercalibration Nov2011.

3. Assessment concept: Comparable for eulittoral methods (DE and SI), Comparable for sublittoral metjods of DE and FR, Different for IT IC Option Assessment methods different and Sampling too different for option 3 (sampling area, sampled habitats, determination level etc.)  Option 2 (common metrics) Methods, Pressures

4. 1 References from another bioregion 2 Circular reasoning involved Conclusions: - Eulittoral Methods (SI, DE) compliant and intercalibratable - Deeper Zone methods compliant with open questions; too late for intercalibration in phase 2 Compliance Checking

5. Data • 173 samples from 19 lakes in 3 countries • Variety of typological, morphological and chemical data • Combined morphology index chosen for standardisation and other analyses consisting of five parameters: • naturalness of shoreline at site level, • combined land use within 15m and 100m at site level, • combined land use within 100m belt at lake level and • %shoreline altered at lake level • IC-Types L-CB1 and L-CB2 in the data, but these were not differentiated, because the differences did not show up in the metrics

6. Benchmarking • Only very few reference lakes / sampling sites reference benchmarking not possible • Too variable results with alternative benchmarking in dependence of the window of pressure used  Continuous benchmarking applied • Linear mixed models with with the biological metrics as dependent variable, the combined pressure variable as covariates and the country as random factor; slope as fixed and intercept as random factors  intercept deviation • Subtraction method for metric standardisation (subtraction of country/type specific intercept deviation from the metric values)

7. Benchmarking Each single metric standardised separately to allow a comparability between countries, metric selection based on combined data and a harmonised multimetric index • Example for faunaindex:

8. Common Metrics * • Standardised single metrics were normalised using 10- and 90-%tiles of all metric values as anchors to get comparable values for the different metrics  1 near reference conditions, 0 at worst status • Calculation of 17 common multimetric index variants; Selection of best variant by correlations with national EQRs (first priority) and pressure parameters • Final intercalibration common metric (ICM) as weighted average of normalised Faunaindex, number of taxa, reproduction strategy (r/k) and % feeding type preference gatherer (based abundance classes), thus covering all WFD criteria (diversity, sensitive/tolerant taxa, composition): • ICM = (2*Faunaindex + no_taxa + r/k + %gatherer)/5 • Neither the ICM nor the single metrics showed differences with regard to the IC-type (L-AL3 and L-AL4)  no further differentiation of IC-types (would have only lowered the number of sites per exercise) * partial financial support by WISER

9. Correlation of Morphology with ICM Pearsson R: AT 0.90, DE 0.42, SI 0.55

10. Correlations of national EQRs with ICM • All correlations highly significant and above acceptance threshold  all accepted

11. Boundary Comparison – Bias in class units G/M H/G No adjustments necessary

12. Final class boundaries

13. Description of communities • Characterisation of good status: • high diversity and abundance of sensitive insect taxa (mainly Ephemeroptera, Trichoptera and Odonata), • dominance of sensitive versus tolerant taxa (leading to a decrease in ASPT, for example), • low ratios of r-strategists in relation to k-strategists and • low portion of indifferent taxa. • More than 200 out of the 1692 taxa of the the IC dataset showed preferences for either high to goodor moderate to bad status. • Examples of frequently found taxa with higher abundances at high or good status include Siphonoperla sp., Sericostoma sp., Leptocerus tineiformis, Gomphus vulgatissimus and Leptophlebia vespertina. • Characterisation of moderate or worse status: • high diversity and abundance of insensitive taxa (mainly Crustaceans and many Chironomids taxa), • dominance of tolerant versus sensitive taxa, • higher ratios of r-strategists in relation to k-strategists and a high portion of indifferent taxa. • Examples of frequently found taxa with higher abundances at moderate or worse status include Corbicula sp., Mysidae Gen. sp., Physa sp., Glossiphonia sp., Chironomini Gen. sp. and Asellidae Gen. sp. as well as some alien taxa like Potamopyrgus sp., Dikerogammarus sp. and Corbicula sp.. • All in all, this reflects a change from more specialised and sensitive taxa towards generalist and tolerant taxa.

14. Gaps • intercalibration exercise of the deeper zone methods still to be done • Austria has no method, because they see no added value for benthic fauna assessment in Austrian lakes  official request sent to the Commission