title: Structural and functional responses of benthic invertebrates to imidacloprid in outdoor stream mesocosms.
abstract: Structural and functional responses of a benthic macroinvertebrate assemblage to pulses of the insecticide imidacloprid were assessed in outdoor stream mesocosms. Imidacloprid pulses reduced invertebrate abundance and community diversity in imidacloprid-dosed streams compared to control streams. These results correlated well with effects of imidacloprid on leaf litter decomposition and feeding rates of Pteronarcys comstocki, a stonefly, in artificial streams. Reductions in oxygen consumption of stoneflies exposed to imidacloprid were also observed in laboratory experiments. Our findings suggest that leaf litter degradation and single species responses can be sensitive ecotoxicological endpoints that can be used as early warning indicators and biomonitoring tools for pesticide contamination. The data generated illustrates the value of mesocosm experiments in environmental assessment and how the consideration of functional and structural endpoints of natural communities together with in situ single species bioassays can improve the evaluation and prediction of pesticide effects on stream ecosystems.
authors.affiliation: CESAM & Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. jpestana@ua.pt
authors.forename: J L T
authors.initials: JL
authors.lastname: Pestana
authors.forename: A C
authors.initials: AC
authors.lastname: Alexander
authors.forename: J M
authors.initials: JM
authors.lastname: Culp
authors.forename: D J
authors.initials: DJ
authors.lastname: Baird
authors.forename: A J
authors.initials: AJ
authors.lastname: Cessna
authors.forename: A M V M
authors.initials: AM
authors.lastname: Soares
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects*; D044822:Biodiversity; D004435:Eating / Q000187:drug effects; D017753:Ecosystem; D004784:Environmental Monitoring; D007093:Imidazoles / Q000633:toxicity*; D007313:Insecta / Q000145:classification / Q000187:drug effects / Q000502:physiology; D007306:Insecticides / Q000633:toxicity; D007448:Invertebrates / Q000187:drug effects*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity*; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D014874:Water Pollutants, Chemical; C082359:imidacloprid