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Title:Songbird community ecology and habitat selection in the Chicago area
Author(s):Cleeton, Sarah
Advisor(s):Miller, James R.
Department / Program:Natural Res & Env Sci
Discipline:Natural Res & Env Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
community ecology
habitat selection
invasive species
Abstract:Urbanization has considerable effects on native flora and fauna, and is likely the most important driver of extinction. Two major stressors that have been shown to strongly impact wildlife communities in urban areas are habitat loss and fragmentation, which expose organisms in remnants to increased stressors associated with edges. Another potential stressor is the encroachment of invasive vegetation. Invasive plants are highly successful colonizers of natural habitats within urban environments, yet their impacts on native fauna remain largely unknown. I was interested in examining how these stressors impacted bird communities. Specifically, I addressed two questions: (1) how do exotic shrub invasions impact woodland songbirds within urban landscapes? and (2), how do bird communities change across forest-suburb boundaries? Field work was conducted in the Chicago metropolitan area during the breeding seasons of 2010 and 2011. I found that even though measures of invasive vegetation were only weakly correlated with avian community structure (i.e. a matrix of all species and their relative abundances at each plot), both species richness and the conservation value of birds within a plot decreased with an increase in European buckthorn (Rhamnus cathartica) tree dominance. I also found that birds that nest and forage in the upper canopy showed negative responses to shrub invasion, while understory species such as the northern cardinal (Cardinalis cardinalis) showed positive responses. Regarding forest-suburb edges, I found that whereas forest bird community composition changed with distance from the edge, the suburban bird community remained homogenous throughout. Similarly, the densities of the most common forest species increased with distance from the edge, while the densities of the most common suburban species fluctuated in a seemingly random fashion with distance from the edge. Lastly, I found evidence that the northern cardinal could be classified as an edge-exploiter. Overall, this research adds to our understanding of the ways that management practices can influence avian responses to local vegetation structure and landscape in metropolitan environments.
Issue Date:2012-05-22
Rights Information:Copyright 2012 Sarah Cleeton
Date Available in IDEALS:2012-05-22
Date Deposited:2012-05

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