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Grantee Research Project Results

NCER Grantee Research Project Results

How Does Livestock Production Impact Wild Bird Health and Gastrointestinal Bacterial Communities?

EPA Grant Number: F07F20142
Title: How Does Livestock Production Impact Wild Bird Health and Gastrointestinal Bacterial Communities?
Investigators: Wheeler, Emily
Institution: University of Illinois at Urbana-Champaign
EPA Project Officer: Just, Theodore J.
Project Period: September 1, 2007 through August 31, 2010
RFA: STAR Graduate Fellowships (2007)
Research Category: Academic Fellowships , Fellowship - Terrestrial Systems Ecology , Fellowship - Ecosystem Health , Fellowship - Microbial Ecology , Ecological Assessment

Description:

Objective:

I will study free-nesting passerine birds as a model for evaluating habitat differences in microbial exposure on gastrointestinal biota (GIB) development and the impacts of varied intestinal microbial community structure on wildlife health. The objective of this project is to explore how variations in bacterial exposures influence the development of gastrointestinal bacterial communities (“gastrointestinal biota” or GIB) in young wild birds, possibly leading to detectible impacts on associated physiological functions. Specifically, my work will address the following questions:

  1. Do wild bird species naturally vary in exposures to microbes in the nest microhabitat during GIB development?
  2. How does adult bird exposure to microbes vary based on different local habitat uses by humans (i.e. livestock production versus semi-natural preserve areas)?
  3. Finally, how do variations in these microbial exposures affect GIB development and do changes in GIB succession in turn, potentially impact fitness via changes in nestling physiology?

Approach:

I will evaluate nestling, maternal and environmental microbial communities using DNA-based bacterial community profiling (t-RFLP) paired with measures of nestling physiology that are likely strongly affected by variations in gastrointestinal communities. Artificial wooden nest boxes will be placed on livestock production sites and in site-matched semi-natural habitat areas in order to evaluate whether nesting in proximity to areas heavily contaminated with livestock manure alters bacterial exposures and GIB establishment of nestling birds, either via differences in nest material availability and/or nest material microbial content or through differences in parental GIB and parental microbial exposures during foraging. I hypothesize that exposure to livestock manure will result in nestling GIB dominated by species found in the associated livestock species as compared to nestlings in semi-natural areas, potentially resulting in decreased growth rates or increased prevalence of gastrointestinal pathogens.

Expected Results:

Many adverse effects of human activities on the availability and quality of wildlife habitat are well established. Evidence is mounting that environmental changes also encourage the emergence of novel human and animal diseases. Modifications of host-pathogen ecology clearly underlie these developments, but there is still limited knowledge of how natural interactions with the broader, non-pathogenic microbial world may be contributing to such changes in disease ecology. This project will explore a relatively unstudied area of avian ecology, wild bird gastrointestinal biota, while also evaluating the role of anthropogenic changes to the environment in altering bacterial exposures, possibly resulting in substantial modifications to avian-microbial community interactions and to host physiology. This study will also assist with evaluating the risk that birds living in proximity to livestock production may pose for perpetuating pathogen cycles on a single site and for disseminating pathogens to surrounding facilities during seasonal changes in habitat use. I will use my research findings to construct a conceptual model of possible critical control points for contacts between wild birds and livestock that encourage bacterial “spill-over” and “spill-back” on farm facilities. My work will contribute to the broader goal of establishing more effective management strategies for reducing disease threats to both wild birds and domestic livestock.

Supplemental Keywords:

wildlife-livestock interactions, avian ecology, exposure, health effects, ecological effects, pathogens, gastrointestinal biota, bacteria, ecology, epidemiology, ecosystem health, passerine, wild bird, nesting ecology, avian reproduction, microbial source tracking, tRFLP, 16sRNA, anthropogenic, environmental change, spill-over, spill-back, environmental impacts, livestock production,

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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