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The influence of predation on the chronic response of Artemia sp. populations to a toxicant.

Beketov MA, Liess M - J Appl Ecol (2006)

Bottom Line: Individuals were exposed for 1 h to the pyrethroid insecticide esfenvalerate (0, 0.01, 0.04 and 0.08 microg L(-1)) and subsequently observed for 6 weeks.Unpredated exposed populations showed a reduced population density compared with the control.The lower density in the exposed populations led to reduced competition and subsequently to enhanced development of surviving individuals and an increased proportion of young individuals.The response of populations of brine shrimp to toxicants at the community level may be stronger when predation is present than the response of populations without predation pressure, as the regulation capacity of the population (measured as an increased production of offspring at reduced population densities) is exhausted when predation is present.

View Article: PubMed Central - PubMed

Affiliation: UFZ-Centre for Environmental Research, Permoserstrasse 15, D-04318 Leipzig, Germany.

ABSTRACT
Environmental risk assessment of contaminants is conventionally based on toxic effects assessed in organism-level test systems. We suggest that, for the prediction of toxicant effects, population- and community-level effects should be considered. The aim of this study was to investigate how predation could alter a prey population's response to a toxicant to reveal effects at population and community levels.Populations of the brine shrimp Artemia sp. were maintained in the laboratory with and without simulated predation. Individuals were exposed for 1 h to the pyrethroid insecticide esfenvalerate (0, 0.01, 0.04 and 0.08 microg L(-1)) and subsequently observed for 6 weeks.Unpredated exposed populations showed a reduced population density compared with the control. However, even at the highest concentration of insecticide, populations were sustained until the end of the experiment. The lower density in the exposed populations led to reduced competition and subsequently to enhanced development of surviving individuals and an increased proportion of young individuals. In contrast, the combination of predation and short-term toxicant exposure at concentrations of 0.04 and 0.08 microg L(-1) produced extinction of the populations after 39 and 32 days of exposure, respectively.Synthesis and applications. The response of populations of brine shrimp to toxicants at the community level may be stronger when predation is present than the response of populations without predation pressure, as the regulation capacity of the population (measured as an increased production of offspring at reduced population densities) is exhausted when predation is present. Future ecotoxicological risk assessment schemes should consider relevant community characteristics such as predation as part of an environmental risk assessment.

No MeSH data available.


Related in: MedlinePlus

Mean densities of G3 and G4 generations (in sum) of Artemia sp. expressed as a percentage of respective controls in different experimental series (unpredated and predated; control, 0·01, 0·04, 0·08 µg L−1) at the end of the experiment (46 days after exposure) (number of individuals, means, %). Asterisks indicate significant (analyses of variance, LSD test, P < 0·005) differences from the control series at the respective time of observation.
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fig03: Mean densities of G3 and G4 generations (in sum) of Artemia sp. expressed as a percentage of respective controls in different experimental series (unpredated and predated; control, 0·01, 0·04, 0·08 µg L−1) at the end of the experiment (46 days after exposure) (number of individuals, means, %). Asterisks indicate significant (analyses of variance, LSD test, P < 0·005) differences from the control series at the respective time of observation.

Mentions: The abundance of the young generations (G3 and G4) was negatively correlated with esfenvalerate concentrations (Fig. 3). In the unpredated populations, the proportion of younger generations (G3 and G4) increased with the increase in toxicant concentration, whereas their abundance did not significantly change in the predated populations. However, for the predated populations this comparison could be made only for the control and lowest exposed populations (0·01 µg L−1) because of mortality at higher exposure concentrations. The densities of these generations expressed as a percentage of the total population density are shown in Fig. 4.


The influence of predation on the chronic response of Artemia sp. populations to a toxicant.

Beketov MA, Liess M - J Appl Ecol (2006)

Mean densities of G3 and G4 generations (in sum) of Artemia sp. expressed as a percentage of respective controls in different experimental series (unpredated and predated; control, 0·01, 0·04, 0·08 µg L−1) at the end of the experiment (46 days after exposure) (number of individuals, means, %). Asterisks indicate significant (analyses of variance, LSD test, P < 0·005) differences from the control series at the respective time of observation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2368765&req=5

fig03: Mean densities of G3 and G4 generations (in sum) of Artemia sp. expressed as a percentage of respective controls in different experimental series (unpredated and predated; control, 0·01, 0·04, 0·08 µg L−1) at the end of the experiment (46 days after exposure) (number of individuals, means, %). Asterisks indicate significant (analyses of variance, LSD test, P < 0·005) differences from the control series at the respective time of observation.
Mentions: The abundance of the young generations (G3 and G4) was negatively correlated with esfenvalerate concentrations (Fig. 3). In the unpredated populations, the proportion of younger generations (G3 and G4) increased with the increase in toxicant concentration, whereas their abundance did not significantly change in the predated populations. However, for the predated populations this comparison could be made only for the control and lowest exposed populations (0·01 µg L−1) because of mortality at higher exposure concentrations. The densities of these generations expressed as a percentage of the total population density are shown in Fig. 4.

Bottom Line: Individuals were exposed for 1 h to the pyrethroid insecticide esfenvalerate (0, 0.01, 0.04 and 0.08 microg L(-1)) and subsequently observed for 6 weeks.Unpredated exposed populations showed a reduced population density compared with the control.The lower density in the exposed populations led to reduced competition and subsequently to enhanced development of surviving individuals and an increased proportion of young individuals.The response of populations of brine shrimp to toxicants at the community level may be stronger when predation is present than the response of populations without predation pressure, as the regulation capacity of the population (measured as an increased production of offspring at reduced population densities) is exhausted when predation is present.

View Article: PubMed Central - PubMed

Affiliation: UFZ-Centre for Environmental Research, Permoserstrasse 15, D-04318 Leipzig, Germany.

ABSTRACT
Environmental risk assessment of contaminants is conventionally based on toxic effects assessed in organism-level test systems. We suggest that, for the prediction of toxicant effects, population- and community-level effects should be considered. The aim of this study was to investigate how predation could alter a prey population's response to a toxicant to reveal effects at population and community levels.Populations of the brine shrimp Artemia sp. were maintained in the laboratory with and without simulated predation. Individuals were exposed for 1 h to the pyrethroid insecticide esfenvalerate (0, 0.01, 0.04 and 0.08 microg L(-1)) and subsequently observed for 6 weeks.Unpredated exposed populations showed a reduced population density compared with the control. However, even at the highest concentration of insecticide, populations were sustained until the end of the experiment. The lower density in the exposed populations led to reduced competition and subsequently to enhanced development of surviving individuals and an increased proportion of young individuals. In contrast, the combination of predation and short-term toxicant exposure at concentrations of 0.04 and 0.08 microg L(-1) produced extinction of the populations after 39 and 32 days of exposure, respectively.Synthesis and applications. The response of populations of brine shrimp to toxicants at the community level may be stronger when predation is present than the response of populations without predation pressure, as the regulation capacity of the population (measured as an increased production of offspring at reduced population densities) is exhausted when predation is present. Future ecotoxicological risk assessment schemes should consider relevant community characteristics such as predation as part of an environmental risk assessment.

No MeSH data available.


Related in: MedlinePlus