RIPARIAN SPIDERS AS SENTINELS OF POLYCHLORINATED BIPHENYL CONTAMINATION ACROSS HETEROGENEOUS AQUATIC ECOSYSTEMS

摘要

Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems. However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinated biphenyls (PCBs) in aquatic ecosystems with high habitat heterogeneity. The spatial pattern of SPCB concentrations in 2 common families of riparian spiders sampled in 2011 to 2013 generally tracked spatial variation in sediment SPCBs across all sites within the Manistique River Great Lakes Area of Concern (AOC), a rivermouth ecosystem located on the south shore of the Upper Peninsula, Manistique (MI, USA) that includes harbor, river, backwater, and lake habitats. Sediment SPCB concentrations normalized for total organic carbon explained 41% of the variation in lipid-normalized spider SPCB concentrations across 11 sites. Furthermore, 2 common riparian spider taxa (Araneidae and Tetragnathidae) were highly correlated (r(2) > 0.78) and had similar mean SPCB concentrations when averaged across all years. The results indicate that riparian spiders may be useful sentinels of relative PCB availability to aquatic and riparian food webs in heterogeneous aquatic ecosystems like rivermouths where habitat and contaminant variability may make the use of aquatic taxa less effective. Furthermore, the present approach appears robust to heterogeneity in shoreline development and riparian vegetation that support different families of large web-building spiders. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC.