Overview phytobenthos EQR for lakes in Flanders, Belgium (BE-FL) Luc Denys Phytobenthos intercalibration London 18-1-2010
Topics typology approach indicators & boundary setting relation to pressures EQR for samples & lakes (aggregation) possible future changes
Lake (and pond) typology altitude lowland saline influence brackish... slightly brackish (Cl - > 300 mgl -1 ) Bzl fresh geology siliceous or organic siliceous or organic siliceous geography ph stratification hydrochemistry coastal dunes (alkaline, TP G/M 45 µgl -1 ) Ad stratified Aw all regions alkaline (ph > 7.5) mixed high mineral content (TP G/M 105 µgl -1 ) Ai Kempen and areas with poorest cover sands in Sandy Flanders moderate mineral content Ami circumneutral (ph 6.5-7.5) weakly acid (ph 6.5-4.7) Zm iron rich CFe well buffered (ALK > 0.2 meql -1 ) Cb strongly acid (ph < 4.7) Zs weakly buffered (ALK < 0.2 meql -1 ) Czb trophic background eutrophic (TP G/M 55 µgl -1 ) Aw-e meso- to oligotrophic (TP G/M 40 µgl -1 ) Aw-om eutrophic (TP G/M 70 µgl -1 ) Ami-e meso- to oligotrophic (TPG/M 45 µgl -1 ) Ami-om
Principles same as rivers; diatoms only integrate pressures (nutrient enrichment + organic pollution + salinisation + acidification + toxicants ) overall status: not for biomonitoring specific pressures distance to target: change in species composition and abundance (not as inferred vs expected TP or a WA-index of indicator values) type-specific indicators and goals only most reliable indicators used % data for summer assemblages on natural firm vertical substrates (preferably Phragmites; exactly 500 valves) presumed planktonic taxa not excluded identifications at lowest taxonomic level
3 Types of indicator taxa % impactsensitive taxa (ISD): optimum at H, low tolerance indifferent taxa: broad tolerance or not distinct for H; or unclear impact-associated taxa (IAD): increase with impact HIGH GOOD MODERATE POOR BAD high status: characterized by dominance of ISD even at high status, IAD may have some abundance (natural variation) at good status, the ISD have decreased; dominance by indifferent ones no indication of significant impact (e.g. dominance weedy species) deviation from good status is indicated by excess of IAD
Dichotomous scale: Proportions of Impact-Sensitive and Impact-Associated Diatoms EQR only % ISD matters only % IAD matters 1 0.8 0.6 0.6 0.4 0.2 0 HIGH GOOD MODERATE POOR BAD 100 % 0 % HIGH HIGH X % treshold ISD impact-sensitive taxa increase treshold IAD impact-associated taxa increase impact-sensitive + indifferent taxa decrease Y % GOOD MODERATE POOR GOOD impact-associated + indifferent taxa decrease BAD 0 % 100 %
Identification of indicators no real contemporary references no natural occurrence of stratified waters historical (1852-1945; 134 samples) vs contemporary assemblages (1997-2003; 139 samples); IndVal per water type: decrease: potential ISD, increase: potential IAD joint clustering of historical and contemporary data followed by IndVal analysis DCCA with: median total inorganic N, total organic N, potential gross oxygen production maximum total phosphorus 20 % taxa with most extreme scores: potential IAD or ISD optima & tolerances from regional calibration (Denys 2007, JOPL 38) literature data & expert judgment
Indicators # Cb Aw-om Aw-e Ami-om Ami-e Ai ISD 202 251 289 125 180 123 IAD 247 235 158 230 120 91 TP G/M (µgl -1 ) 40 40 55 45 70 105 Cb Aw-om Aw-e Ami-om Ami-e Ai Achnanthidium minutissimum - - - - - ISD Amphora copulata IAD IAD - IAD - - Aulacoseira tenella ISD ISD ISD - - - Cocconeis placentula IAD IAD - IAD - - Encyonopsis microcephala ISD ISD ISD ISD ISD ISD Eolimna subminuscula IAD IAD IAD IAD IAD IAD Epithemia turgida IAD IAD - IAD ISD ISD
Boundary setting water bodies with chl a or TP: < H/G: 75 and 90 percentile % ISD < G/M: 75 and 90 percentile % IAD historical assemblages (< 1945; more stringent): 90 and 75 percentiles IAD & ISD assumed 75-90 % WBs were G or better; 10-25 % were H G/M boundaries chosen according to expected trophic status for type H/G boundaries based on most stringest result other boundaries at equal intervals
Boundaries EQR criterium Cb Aw Ami-om Ami-e Ai 1 ref. % ISD 85 70 80 70 80 0.8 H/G % ISD 70 40 60 40 60 0.6 G/M % IAD 25 20 10 25 25 0.4 M/P % IAD 50 45 40 50 50 0.2 P/B % IAD 75 75 70 75 75
Relation to pressures? EQR > 0.6: clear, nutrients not very high EQR < 0.6: chlorophyll, phosphorus & nitrogen vary 350 7 9 chl a (median; µg/l) 300 250 200 150 100 50 R 2 = 0.06 TP (maximum; mg/l) 6 5 4 3 2 1 R 2 = 0.15 TIN (median; mg/l) 8 7 6 5 4 3 2 1 R 2 = 0.01 0 0 0 0.00 0.20 0.40 0.60 0.80 1.00 0.00 0.20 0.40 0.60 0.80 1.00 0.00 0.20 0.40 0.60 0.80 1.00 EQR EQR EQR less stringent than German method (not restricted to large WBs, lowlands )
Within-lake variation considerable spatial differences in some WBs considerable differences between successive years in some WBs now every 3 yrs (difficult to increase) 3 Kessenich 2006 (N = 7): EKR = 0,43 +/- 0,13 0.14 Heerenlaak 2006 (N = 9): EKR = 0,47+/- 0,13 0.22 0.43 good moderate poor 0.44 good moderate poor 0.43 0.33 Heerenlaak 2007 Kessenich 2007 (N = 7): EKR = 0,59 +/- 0,07 Heerenlaak 2007 (N = 4): EKR = 0,47+/- 0,17 K8/7 Kessenich 2007 Kessenich 2006 Herenlaak 2006 0.29 good moderate 0.25 0.25 good moderate poor 0.71 0.50 0 3
Number of samples: flexible nr. of samples to estimate average EQR with E = 0.1 or 0.2 EQR units for several WBs with 3-9 replicate samples: 3 often OK for E = 0.2 always 9 samples / WB (= maximum analyzed; at least 50 ha) at least 3 analyzed - 3 chosen according to max. expected variation - additional samples until SD < 0.2 EQRs averaged
Modification 1 presently considered 100 % % ISD treshold G/H X H counting error on estimate 0 % G Y treshold G/M M/P P/B % IAD additional criterium to avoid undesired H/M transitions: maximum treshold for IAD at H (references) M P B 100 %
Modification 2 presently considered 250 valves 500 valves areas with classification confidence 95 % (black, simulated) pool counts to calculate EQR WB? 1000 valves 1500 valves
Reports lake phytobenthos WFD in Flanders Hendrickx A. & L. Denys (2005) Toepassing van verschillende biologische beoordelingssystemen op Vlaamse potentiële interkalibratielocaties overeenkomstig de Europese Kaderrichtlijn Water Partim Fytobenthos. Rapport Instituut voor Natuurbehoud IN.R.2005.06. Lock K., Van Wichelen J., Packet J., Simoens I., Van Looy K., Louette G., Warmoes T. & L. Denys (2007) Bepalen van het maximaal en het goed ecologisch potentieel, alsook de huidige toestand, voor een aantal Vlaamse (gewestelijke) waterlichamen die vergelijkbaar zijn met de categorie meren. Deel 1. Rapport Instituut voor Natuur- en Bosonderzoek INBO.R.2007.87. Louette G., Van Wichelen J., Packet J., Warmoes T. & L. Denys (2008) Bepalen van het maximaal en het goed ecologisch potentieel, alsook de huidige toestand voor de zeventien Vlaamse (gewestelijke) waterlichamen die vergelijkbaar zijn met de categorie meren tweede deel, partim Grote Vijver Mechelen. Rapport Instituut voor Natuur- en Bosonderzoek INBO.R.2008.49. Louette G., Van Wichelen J., Packet J., De Smedt S. & L. Denys (2008) Bepalen van het maximaal en het goed ecologisch potentieel, alsook de huidige toestand voor de zeventien Vlaamse (gewestelijke) waterlichamen die vergelijkbaar zijn met de categorie meren tweede deel, partim Blokkersdijk. Rapport Instituut voor Natuur- en Bosonderzoek INBO.R.2008.48. Louette G., Van Wichelen J., Packet J., Warmoes T. & L. Denys (2008) Bepalen van het maximaal en het goed ecologisch potentieel, alsook de huidige toestand voor de zeventien Vlaamse (gewestelijke) waterlichamen die vergelijkbaar zijn met de categorie meren tweede deel, partim Schulensmeer. Rapport Instituut voor Natuur- en Bosonderzoek INBO.R.2008.49. Louette G., Van Wichelen J., Packet J., Warmoes T. & L. Denys (2008) Bepalen van het maximaal en het goed ecologisch potentieel, alsook de huidige toestand voor de zeventien Vlaamse (gewestelijke) waterlichamen die vergelijkbaar zijn met de categorie meren tweede deel, partim Vinne. Rapport Instituut voor Natuur- en Bosonderzoek INBO.R.2008.50. In preparation - Biological assessment of the natural, heavily modified and artificial surface water bodies in Flanders according to the European Water Framework Directive. Vlaamse Milieumaatschappij.