Alpine GIG phytoplankton group ECOSTAT | 27 June 2011 Georg Wolfram

Member States Špela Remec-Rekar Eberhard Hoehn Ursula Riedmüller LBH Christophe Laplace-Treyture Cemagref Georg Wolfram DWS Hydro-Ökologie GmbH Maria Friedl Kärntner Inst. f. Seenforschung Fabio Buzzi Arpa Lombardia Giuseppe Morabito CNR, Istituto per lo Studio degli Ecosistemi Špela Remec-Rekar Environmental Agency of the Republic of Slovenia

Alpine GIG – an easy job? Small and homogenous GIG Few MS and full participation Little variability in lake types (50 – 800 m a.s.l.) Long data series (since 1930s) Comparable sampling and analytical methods Clear pressure – impact relationship

1 pressure – 2 parameters – 4 methods Pressure = eutrophication Biomass (chlorophyll-a and/or biovolume) + Taxonomical composition (trophic index) Finalized methods in AT(+SI), GE, FR and IT

Alpine blooms? WISER deliverable: rare at TP <20–25 µg L–1 Annex V of WFD: “Persistent blooms may occur” The risk of missing a bloom is thus very high  high uncertainty and stochasticity In order not to add a metric with high uncertainty and little relevance to the existing, well working assessment methods, the Alpine GIG has agreed not to include blooms in their classification systems.

Overview of Methods MS biomass tax. composition chl-a biovolume trophic index AT avg avg Brettum index FR avg – MCS GE avg/max avg PTSI + algal classes IT avg avg PTI SI avg avg Brettum index blue = annual mean, red = mean of vegetation season

Combination rules AT + SI + IT Total biovolume EQR nEQR nEQR Arithmetic mean Chlorophyll-a EQR nEQR nEQR Arithmetic mean Trophic index EQR nEQR

Reference conditions Tiered approach for defining reference conditions Definition of general reference criteria for lakes Definition of reference criteria for lakes, for single BQE only Definition of reference criteria for sites (within lakes) Key criteria for phytoplankton: TP concentration ≤ 8 µg L–1 (L-AL3) ≤ 12 µg L–1 (L-AL4) Modified approach GE: using LAWA index FR: emphasis on land use and population density

Reference conditions Lake (n = 1 – 9) TP ann.avg TP spring circ Chl-a BV Achensee 4 1.13 0.09 Alpsee bei Füssen 6 1.33 0.43 Altausseer See 1.35 0.16 Attersee 2 3 1.23 0.36 Bohinjsko jezero 5 1.20 0.12 Eibsee 1.44 0.21 Fuschlsee 0.55 Grundlsee 0.90 0.07 Heiterwanger See 1.29 0.13 Königssee 1.66 0.39 Millstätter See 0.29 Obersee 3.06 0.51 Ossiacher See 0.41 Plansee Starnberger See 7 2.06 0.57 Sylvensteinsee 1.19 0.14 Traunsee 2.00 0.52 Walchensee 1.88 Weißensee 0.22 Wolfgangsee G Wolfgangsee W 0.23 Wörthersee Zeller See 0.45

Reference conditions TP ann. avg TP spring circ. Chl-a BV mean 5 4 1.52 0.30 median 1.33 0.29 min 2 0.90 0.07 max 7 6 3.06 0.57 75%perc 1.77 0.42 90%perc 2.04 0.52 95%perc 2.36 0.55

Reference conditions L-AL3 reference value H/G boundary phase 1 0,60 ranges 0,50 0,40 ranges Total biovolume [mm3 L-1] 0,30 0,20 0,10 0,00 median 90%p 70%p 90%p 95%p phase 1 new calculation

Reference conditions L-AL3 reference value H/G boundary 3,00 2,50 2,00 chlorophyll-a [µg L-1] 1,50 1,00 0,50 0,00 median 90%p 70%p 90%p 95%p

Reference conditions New calculations: roughly the same results for reference values and H/G boundary (changes especially in percentiles)  decided to keep the old values from phase 1

Benchmark standardization Benchmark standardization serves to homogenize the EQR results of common datasets where needed, minimising typological and methodological differences between the Member states which may otherwise influence the comparability of their classifications (especially: biogeographical differences).

Benchmark standardization L-AL4

Benchmark standardization L-AL3

Benchmark standardization Comparability checking without benchmark standardization By manually setting the offset to zero

Boundary comparison

Boundary comparison 1. Relatedness 2. Boundary bias   2. Boundary bias 3. Class difference Regressions with PCM H/G bias_CW Absolute Class Diff. L-AL3 L-AL4 AT/SI - PCM 0,87 0,86 AT/SI -0,10 0,32 FR - PCM 0,34 0,50 FR -0,07 0,15 0,47 0,53 GE - PCM 0,79 0,85 GE 0,04 0,33 0,30 IT - PCM 0,83 0,88 IT 0,01 -0,12 0,29 min/max 40% 57% G/M bias_CW Count 570 276 Pearsson corr. coeff. -0,11 0,13 0,93 -0,01 0,59 0,71 0,10 0,89 0,92 0,00 -0,20 0,91 0,94 min R2 < ½ max R2 boundary biases ≤0.25 correlation coefficients ≥ 0.5 avg absolute class difference <1.0

Summary All MS have submitted national methods Only slight deviation from phase 1 results Good agreement between national methods IC completed

Comparison of BQEs lake IC type phytopl macroph fish key pressure final ATT L-AL3 0.93   0.92 morph littoral MATT L-AL4 0.90 0.79 ALT 0.86 bathing WOLF 0.80 shipping FAAK 1.00 0.53 hymo OBTR 0.62 eu WORTH 0.65 0.68 MILL 0.67 0.59 MOND 0.69 0.77

Thank you