title: Environmental impact propagated by cross-system subsidy: chronic stream pollution controls riparian spider populations.
abstract: Resource subsidies between habitats are common and create the potential for the propagation of environmental impacts across system boundaries. However, recent understanding of the potential for subsidy-mediated cross-system impact propagations is limited and primarily based on passive flows of nutrients and detritus or short-term effects. Here, we assess the effects of sustained alterations in aquatic insect emergence (active subsidy pathway), due to chronic stream pollution, for riparian spiders. The sustained reduction in aquatic insect densities at the polluted reaches resulted in a marked decline in web spider population density and a shift in spider community composition. Our results provide the first evidence that stream pollution can control populations and community structure of terrestrial predators via sustained alterations in aquatic subsidies, emphasizing the role of subtle trophic linkages in the transmission of environmental impacts across ecosystem boundaries.
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom. a.paetzold@gmx.net
authors.forename: Achim
authors.initials: A
authors.lastname: Paetzold
authors.forename: Marian
authors.initials: M
authors.lastname: Smith
authors.forename: Philip H
authors.initials: PH
authors.lastname: Warren
authors.forename: Lorraine
authors.initials: L
authors.lastname: Maltby
mesh_terms: D000818:Animals; D017753:Ecosystem; D004777:Environment; D004784:Environmental Monitoring; D007313:Insecta / Q000187:drug effects; D007814:Larva / Q000187:drug effects; D013112:Spiders / Q000187:drug effects* / Q000502:physiology*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical