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Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities

Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladoc...

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Autores principales: Brogan, William R., Relyea, Rick A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4433326/
https://www.ncbi.nlm.nih.gov/pubmed/25978686
http://dx.doi.org/10.1371/journal.pone.0126677
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author Brogan, William R.
Relyea, Rick A.
author_facet Brogan, William R.
Relyea, Rick A.
author_sort Brogan, William R.
collection PubMed
description Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses) have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm) crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses) on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades). However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern. Our findings suggest that facilitating macrophytes could be an important strategy for buffering freshwater communities from insecticides, though consideration of their impacts on animal species is necessary.
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spelling pubmed-44333262015-05-27 Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities Brogan, William R. Relyea, Rick A. PLoS One Research Article Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses) have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm) crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses) on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades). However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern. Our findings suggest that facilitating macrophytes could be an important strategy for buffering freshwater communities from insecticides, though consideration of their impacts on animal species is necessary. Public Library of Science 2015-05-15 /pmc/articles/PMC4433326/ /pubmed/25978686 http://dx.doi.org/10.1371/journal.pone.0126677 Text en © 2015 Brogan, Relyea http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Brogan, William R.
Relyea, Rick A.
Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities
title Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities
title_full Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities
title_fullStr Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities
title_full_unstemmed Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities
title_short Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities
title_sort submerged macrophytes mitigate direct and indirect insecticide effects in freshwater communities
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4433326/
https://www.ncbi.nlm.nih.gov/pubmed/25978686
http://dx.doi.org/10.1371/journal.pone.0126677
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