Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA

Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA

Bibliographic Details
Main Author: Rowse, Linnea M.
Language:English
Published: The Ohio State University / OhioLINK 2013
Subjects:
Toxicology
Wildlife Management
Mercury
Acadian Flycatcher
reproductive success
contaminant pathways
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1374082536
id ndltd-OhioLink-oai-etd.ohiolink.edu-osu1374082536
record_format oai_dc
collection NDLTD
language English
sources NDLTD
topic Toxicology
Wildlife Management
Mercury
Acadian Flycatcher
reproductive success
contaminant pathways
spellingShingle Toxicology
Wildlife Management
Mercury
Acadian Flycatcher
reproductive success
contaminant pathways
Rowse, Linnea M.
Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA
author Rowse, Linnea M.
author_facet Rowse, Linnea M.
author_sort Rowse, Linnea M.
title Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA
title_short Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA
title_full Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA
title_fullStr Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA
title_full_unstemmed Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA
title_sort pathways and consequences of contaminant flux to acadian flycatchers (empidonax virescens) in urbanizing landscapes of ohio, usa
publisher The Ohio State University / OhioLINK
publishDate 2013
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1374082536
work_keys_str_mv AT rowselinneam pathwaysandconsequencesofcontaminantfluxtoacadianflycatchersempidonaxvirescensinurbanizinglandscapesofohiousa
_version_ 1719434444676268032
spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu13740825362021-08-03T06:18:40Z Pathways and Consequences of Contaminant Flux to Acadian Flycatchers (Empidonax virescens) in Urbanizing Landscapes of Ohio, USA Rowse, Linnea M. Toxicology Wildlife Management Mercury Acadian Flycatcher reproductive success contaminant pathways Increases in urbanization with a growing global population can result in diverse threats to wildlife, including exposure to harmful contaminants. Among environmental contaminants hazardous to humans and wildlife, mercury is of special concern due to its prevalence, mobility in aquatic systems, and persistence in sediments. Aquatic systems, in particular, can have high amounts of mercury in its bioavailable form, which can bioaccumulate in insects and transfer to terrestrial food webs (i.e., to aerial insectivores). Such contaminant flux from aquatic to terrestrial systems is expected to disproportionately affect species reliant upon aquatic emergent insects. To understand the pathways of contaminant flux and their role in reproductive success, I addressed two questions: (1) Is avian exposure to contaminants influenced by territory placement? and (2) Do contaminant loads negatively impact condition and reproductive success? From April-August 2011-2012 I tracked reproductive success of Acadian flycatchers (Empidonax virescens) in 19 riparian forest fragments located across a land-use gradient in central Ohio, USA. I collected blood samples from adult (n = 76) and nestling (n = 17) flycatchers and samples from riparian systems (sediment, aquatic emergent insect, and water) to examine relationships between landscape factors and contaminant concentrations. I used reproductive data and flycatcher contaminant loads to evaluate mercury’s impact on productivity and condition of adult flycatchers. Factors most responsible for contaminant transfer to flycatchers remain unclear. Landscape factors, including proximity of territories to rivers, and urbanization surrounding forest sites, were not related to mercury levels in flycatchers, sediment, water, or insects. However, when separately analyzed, I detected a positive relationship between mercury in flycatchers and sediments in urban landscapes, and an opposite, negative relationship, in rural landscapes. Unlike previous research, mercury concentrations in aquatic insects were not predicted by concentrations in sediments. The overall lack of concordance among mercury levels in flycatchers, aquatic insects, and sediments raises the possibility that flycatchers consumed less aquatic prey than expected or that the common aquatic insects were not the most important vectors of aquatic-to-terrestrial contaminant flux. Although levels of mercury in Acadian flycatcher blood in this study were relatively low and appeared not to affect body condition, productivity declined with increasing mercury loads. My results are consistent with other studies that have documented reduced reproductive success in contaminated areas, though mercury loads were at trace levels in the flycatchers I studied. Reduced productivity in my study system could possibly be explained by changes in adult behavior or egg hatching success, driven by sublethal effects of mercury in flycatchers; these factors need to be further examined.As a whole, my research contributes to a growing body of knowledge regarding pathways for contaminant flux from aquatic to terrestrial systems, and to our understanding of mercury contamination effects on songbirds. My research suggests that pathways for contaminant flux from aquatic to terrestrial systems are complex and do not always follow predictable routes. Moreover, that reduced productivity was associated with trace levels of mercury is a cautionary note that wildlife managers should not dismiss impacts of trace levels of contaminants that biomagnify. 2013-09-27 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1374082536 http://rave.ohiolink.edu/etdc/view?acc_num=osu1374082536 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

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