08/05/2014 Interaction between stress induced by Introduction - PDF document

08/05/2014 Interaction between stress induced by Introduction competition and an insecticide on the  ERA based on extrapolations from single-species tests to response of aquatic invertebrates the whole ecosystem  Ecological interactions are not taken into account Paul J. van den Brink, Sylvan Klein, Andreu Rico  Effects on sensitive populations could be underestimated Objective Gammarus pulex experiment  Glass jars with 1L filtered pond water  To study how and to what extent ecological interactions  Water bath (T=15°C; 12h photoperiod) influence the effects of chemicals on aquatic  Food source: 3.5 mg poplar leaf fragments ( Populus nigra L.) invertebrate populations  Competition ( n =3):  Two experiments: ● Gammarus pulex ( Amphipoda ) vs I ntraspecific I nterspecific Asellus aquaticus ( Isopoda ) 5 G. pulex 5 G. pulex Control ● Daphnia pulex (Cladocera) vs or Brachionus calyciflorus (Rotifera) 5 G. pulex + 10 G. pulex Low 5 A. aquaticus vs Chaoborus sp. larvae (Insecta) 5 G. pulex + 15 G. pulex Medium ● Chlorpyrifos (OP insecticide) 10 A. aquaticus 5 G. pulex + High 15 A. aquaticus Gammarus pulex experiment Gammarus pulex experiment  Chlorpyrifos: Control, 0.15, 0.20, 0.25 µg/L  Statistical analyses  Representing the LC0, LC10, LC30 and LC50 (Rubach et al. 2011) ● Effects of pesticide, competition treatment and  Pesticide application: their interaction ● Generalized Liner Models (GLMs) with GenStat Pre-treatment Exposure period ( 1 4 d ) ( 2 d ) Abundance = α + CPF + Competition + Inter. CPF CPF ● Binomial distribution with a logit link ● G. pulex experiment: EC50s  Survival: day 0, 2, 4, 7, 11, 14 after the first application 1

08/05/2014 Gammarus pulex experiment Gammarus pulex experiment  Intraspecific competition  Interspecific competition Pesticide Concentration Pesticide Concentration 0 .1 5 µg/L 0 .2 0 µg/L 0 .2 5 µg/L Control 0 .1 5 µg/L 0 .2 0 µg/L 0 .2 5 µg/L Control 100 100 100 100 100 100 100 100 % Survival % Survival 80 80 80 80 80 80 80 80 % survival % survival % survival % survival % survival 60 60 60 60 60 60 60 60 40 40 40 40 40 40 40 40 20 20 20 20 20 20 20 20 0 0 0 0 0 0 0 0 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 ‐ 2 0 2 4 7 11 14 Day Day surviv Day Day survi Competition level: Competition level: Day % Control val Day Day Low Medium % Control Low Medium High Day al  Sign. effect (day 4 and 7)  Sign. effect (all sampling days)   Density Survival Density A. aquaticus Survival G. pulex  EC50-7d: Control 0.07 - Low 0.09 - Medium 0.12 µg/L  EC50-7d: Control 0.07 - Low 0.18 - Medium >0.25 - High >0.25 µg/L Daphnia pulex experiment Daphnia pulex experiment  Glass jars with 1L WC-medium  Chlorpyrifos: Control, 0.10, 0.40, 0.75 µg/L  Water bath (T=20°C; 12h photoperiod)  Representing the EC0, EC10, EC30 and EC50 (pre-test)  Food source: Scenedesmus obliquus (0.5g/C per jar)  Pesticide application:  Competition and predation ( n =3): Pre-treatment Exposure period ( 2 1 d ) I ntraspecific I nterspecific Predation ( 3 d ) CPF CPF CPF 10 D. pulex 10 D. pulex 40 D. pulex Control 10 D. pulex + 10 D. pulex + 20 D. pulex Low 333 B. calyciflorus 1 Chaoborus sp. 10 D. pulex + 40 D. pulex Medium 666 B. calyciflorus  Abundance: day 0, 2, 4, 7, 14, 21 after the first application 10 D. pulex + High 999 B. calyciflorus  Separated into age classes: adults, sub-adults, juveniles 20% adults 80% sub-adults Daphnia pulex experiment Daphnia pulex experiment  Intraspecific competition  Statistical analyses Pesticide Concentration ● Effects of pesticide, competition/predation treatment and their interaction 0 .1 0 µg/L 0 .4 0 µg/L 0 .7 5 µg/L Control 1000 1000 1000 1000 ● Generalized Liner Models (GLMs) with GenStat Number/L 100 100 100 100 10 10 10 10 Abundance = α + CPF + Competition/Predation + Inter. 1 1 1 1 ‐ 3 0 2 4 7 14 21 ‐ 3 0 2 4 7 14 21 ‐ 3 0 2 4 7 14 21 ‐ 3 0 2 4 7 14 21 Day ● D. pulex : Poisson distribution with a log link Day Day Day Competition level: Control Low Medium  CPF effects only after 2 nd application  No sign. effects of competition  Sign. decrease juveniles and sub-adults highest exposure 2

08/05/2014 Daphnia pulex experiment Daphnia pulex experiment  Interspecific competition  Predation Pesticide Concentration Pesticide Concentration 0 .1 0 µg/L 0 .4 0 µg/L 0 .7 5 µg/L 0 .1 0 µg/L 0 .4 0 µg/L Control 0 .7 5 µg/L Control 1000 1000 1000 1000 1000 1000 1000 1000 Num ber/ L Number/L 100 100 100 100 100 100 100 100 10 10 10 10 10 10 10 10 1 1 1 1 1 1 1 1 ‐ 3 0 2 4 7 14 21 ‐ 3 0 2 4 7 14 21 ‐ 3 0 2 4 7 14 21 ‐ 3 0 2 4 7 14 21 -3 0 2 4 7 14 21 -3 0 2 4 7 14 21 -3 0 2 4 7 14 21 -3 0 2 4 7 14 21 Day Day Day Competition level: Control Predation Control Low Medium High Competition level: Days  Low exposure, competition favours survival  Sign. effect (day 2, 4, 7)  No sign. effects of competition  Largest effects at controls and low exposure  Sign. decrease sub-adults at highest exposure (day 14)  Sing. increase of adults/juveniles with concentration Conclusions Conclusions  Gammarus pulex experiment  Stress by ecological interactions does not necessarily result in higher toxic effects at population level ● Antagonism between pesticide exposure and  Predation seems to result in more evident effects than competition competition ● Intraspecific: social behaviour/cannibalism?  Effects of competition on pesticide sensitivity more ● Interspecific: predation complex than expected  Daphnia pulex experiment  Species and context specific e.g. cannibalism/predation ● Competition effects more evident on population  Inclusion in intermediate tiers of ERA is still challenging structure than on species abundance  Valuable information for ecological models used in ● Predation results in higher effects than competition (Poster WE055) higher-tiers of ERA ● Effects of predation are lower at high exposure concentrations Thanks for your attention ChimERA : an integrated modelling tool for ecological risk assessment – towards more ecologically realistic assessment of chemicals in the environment Kindly funded by: 3