Pathways and consequences of contaminant flux to Acadian flycatchers (Empidonax virescens) in urbanizing landscapes of Ohio, USA.

摘要: article i nfo A prevalent environmental contaminant, mercury (Hg) is mobile and persistent in aquatic systems, where it often occurs its bioavailable form methylmercury. Because methylmercury can bioaccumulate in- sectsandthentransfertoterrestrial foodwebs,riparianconsumersreliantupon aquaticemergentinsects,should be disproportionately affected. Using the aerial insectivore Acadian flycatcher (Empidonax virescens) as a focal species, we examined (1) extent to which total Hg loads breeding flycatchers affected body condition reproductive output (2) potential pathways of contaminant flux 19 riparian forest fragments distrib- uted across an urban-to-rural landscape gradient Ohio, USA. From April-August 2011-2012, collected blood samplesfrom adult(n= 76)and nestling(n=17from7nests)flycatchers,monitoredtheirannualrepro- ductive success (i.e., number fledglings), sampled water, sediment, emergent insects at each site. concentrations adult (47 584 μg/kg, x =2 11.8,SD = 95.5) were low relative published advisory levels not related condition. However, even concentrations, was negatively success, with 0.83 decline fledglings per μg/kg (loge) increaseof Hg. Adult had 11× greaterconcentrations bloodHgthantheir offspring. Hglevels predicted by or insects, exception rural landscapes alone, sediment In addition illustrating difficulty predicting exposure that may vary among contexts, our study provides evidence trace contaminants impair free- living songbirds.