Influence of isolation on the recovery of pond mesocosms from the application of an insecticide. II. Benthic macroinvertebrate responses

Autor: Marc Roucaute, Mark L. Hanson, Laurent Lagadic, Thierry Caquet, David W. Graham
Přispěvatelé: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Department of Civil, Environmental, and Architectural Engineering, University of Kansas [Lawrence] (KU), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
Rok vydání: 2007
Předmět:
Zdroj: Environmental Toxicology and Chemistry
Environmental Toxicology and Chemistry, Wiley, 2007, 26 (6), pp.1280-1290. ⟨10.1897/06-250R.1⟩
ISSN: 1552-8618
0730-7268
DOI: 10.1897/06-250r.1
Popis: The immediate response and recovery of the macrobenthic communities of nonisolated and isolated freshwater outdoor 9 ml mesocosms following an acute stress caused by the addition of deltamethrin were studied over a 14-month period. To discriminate between internal and external recovery mechanisms, half of the treated ponds were covered by 1-mm mesh lids that restricted aerial recolonization. Both structural (abundance of the different taxonomic groups) and functional (litter breakdown) parameters were monitored. Insects were broadly reduced in numbers by deltamethrin addition. In general, noninsect groups were not affected or increased in abundance in deltamethrin-treated ponds, probably because of relative insensitivity to deltamethrin, reduced predation, and lower competition for food. No major change in litter breakdown rates were seen, probably because of functional redundancy among the macrobenthic community. Chironominae larvae recovered in open, treated mesocosms 62 d after deltamethrin addition and most insect groups recovered 84 d after the treatment date. However, the presence of lids significantly reduced insect recovery rate, suggesting that it largely depends on the immigration of winged forms (i.e., external recovery) from surrounding non- or less affected systems. These results indicate that the recovery time of macrobenthic communities in an affected natural pond would depend on spatial characteristics of the landscape and also the season that exposure occurs. Isolated ecosystems would display posttreatment insect recovery dynamics very different from highly connected ones, evolving toward alternate pseudoequilibrium states, possibly with lower biodiversity but with preserved functionality. Consequences for higher tier risk assessment of pesticides are discussed.
Databáze: OpenAIRE
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