title: Effects of intra- and interspecific competition on the sensitivity of aquatic macroinvertebrates to carbendazim.
abstract: The Ecological Risk Assessment of pesticides and other potentially toxic chemicals is generally based on toxicity data obtained from single-species laboratory experiments. In the field, however, contaminant effects are ubiquitously co-occurring with ecological interactions such as species competition and predation, which might influence the sensitivity of the individuals exposed to toxicants. The present experimental study investigated how intra- and interspecific competition influence the response of sensitive aquatic organisms to a pesticide. For this, the effects of the fungicide carbendazim were assessed on the mortality and growth of the snail Bithynia tentaculata and the crustacean Gammarus pulex under different levels of intraspecific and interspecific competition for a food resource. Interspecific competition was created by adding individuals of Radix peregra and Asellus aquaticus, respectively. The interaction of competition and carbendazim exposure significantly influenced B. tentaculata growth, however, combined effects on survival and immobility were considered transient and were less easily demonstrated. Positive influence of competition on G. pulex survival was observed under low-medium carbendazim concentrations and under medium-high density pressures, being partly related to cannibalistic and predation compensatory mechanisms, enhanced under food limiting conditions. This study shows that intra- and interspecific competition pressure may influence the response of sensitive aquatic organisms in a more complex way (positive, non-significant and negative effects were observed) than just increasing the sensitivity of the studied species, as has generally been hypothesized.
authors.affiliation: Department of Plant Biology, Animal Biology and Ecology, Jaén University, B3-078 Campus de las Lagunillas s/n, 23071 Jaén, Spain. Electronic address: aarco@ujaen.es.
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Del Arco
authors.affiliation: Department of Plant Biology, Animal Biology and Ecology, Jaén University, B3-078 Campus de las Lagunillas s/n, 23071 Jaén, Spain.
authors.forename: Gema
authors.initials: G
authors.lastname: Parra
authors.affiliation: Alterra, Wageningen University and Research centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors.forename: Andreu
authors.initials: A
authors.lastname: Rico
authors.affiliation: Alterra, Wageningen University and Research centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Department of Aquatic Ecology and Water Quality Management, Wageningen University, Wageningen University and Research centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Van den Brink
mesh_terms: D033304:Amphipoda / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001562:Benzimidazoles / Q000633:toxicity*; D002219:Carbamates / Q000633:toxicity*; D003163:Competitive Behavior / Q000502:physiology; D017753:Ecosystem; D005247:Feeding Behavior / Q000187:drug effects*; D005659:Fungicides, Industrial / Q000633:toxicity*; D033321:Isopoda / Q000187:drug effects*; D012908:Snails / Q000187:drug effects* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D005659:Fungicides, Industrial; D014874:Water Pollutants, Chemical; C006698:carbendazim
keywords: Carbendazim; Competition; Ecological risk assessment; Pesticides; Population ecotoxicology