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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 different generations (G1, G2, G3 and G4) of Artemia sp. before and after 1 h of exposure to esfenvalerate (control, 0·01, 0·04, 0·08 µg L−1) with and without simulated predation.
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fig02: Mean densities of different generations (G1, G2, G3 and G4) of Artemia sp. before and after 1 h of exposure to esfenvalerate (control, 0·01, 0·04, 0·08 µg L−1) with and without simulated predation.

Mentions: The oldest generation (extant 3 days before the exposure) was termed the G1 generation and subsequent generations were numbered consecutively. At the moment of exposure all the populations consisted of two generations (G1 and G2; Fig. 2). Simulated predation resulted in an increase in developmental rate. Thus in the control and at 0·01 and 0·04 µg L−1 toxicant concentrations, the G3 generation (offspring of G1) appeared in the predated populations at 11 days after exposure, but in the unpredated series this G3 generation started to appear only after 18 days. Esfenvalerate at a concentration of 0·08 µg L−1 caused early reproduction by the G1 generation, and therefore the G3 generation occurred immediately after exposure in the predated and unpredated populations (Fig. 2).


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 different generations (G1, G2, G3 and G4) of Artemia sp. before and after 1 h of exposure to esfenvalerate (control, 0·01, 0·04, 0·08 µg L−1) with and without simulated predation.
© Copyright Policy
Related In: Results  -  Collection

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

fig02: Mean densities of different generations (G1, G2, G3 and G4) of Artemia sp. before and after 1 h of exposure to esfenvalerate (control, 0·01, 0·04, 0·08 µg L−1) with and without simulated predation.
Mentions: The oldest generation (extant 3 days before the exposure) was termed the G1 generation and subsequent generations were numbered consecutively. At the moment of exposure all the populations consisted of two generations (G1 and G2; Fig. 2). Simulated predation resulted in an increase in developmental rate. Thus in the control and at 0·01 and 0·04 µg L−1 toxicant concentrations, the G3 generation (offspring of G1) appeared in the predated populations at 11 days after exposure, but in the unpredated series this G3 generation started to appear only after 18 days. Esfenvalerate at a concentration of 0·08 µg L−1 caused early reproduction by the G1 generation, and therefore the G3 generation occurred immediately after exposure in the predated and unpredated populations (Fig. 2).

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