Term of Award

Summer 2010

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Department

Department of Biology

Committee Chair

C. Ray Chandler

Committee Member 1

Lissa Leege

Committee Member 2

Lance McBrayer

Abstract

Bottomland hardwood forests (bottomlands) dominate most of the river floodplains and lowlands of the southeastern United States. These vanishing and often degraded forests provide habitat for at least seventy species of breeding birds. However, little is known about habitat associations of breeding birds, specifically within mature, closed-canopy bottomlands. It is often assumed that once bottomlands become mature, closed-canopy forests, that they are essentially identical from the perspective of breeding birds. To test this assumption, I examined habitat associations of the overall breeding bird community as well as ten priority species within the little-studied mature bottomlands of the Altamaha River, Georgia. In 2007 and 2008, I conducted point-counts for breeding birds and quantified habitat characteristics at 54 stations. I detected 33 species of birds breeding at stations, 19 of which were Neotropical Migratory bird species. I found that the overall density of breeding birds, the density of breeding Neotropical species, as well as the Avian Conservation Score of stations did not closely track habitat variation within mature bottomlands. However, I found that some individual breeding species were sensitive to habitat variation within mature bottomlands. Yellow-throated vireo (Vireo flavifrons) and Hooded Warbler (Wilsonia citrina) preferred slightly less canopy cover within mature bottomlands, whereas White-eyed vireo (Vireo griseus) preferred more. Kentucky Warbler (Oporonus formosus) preferred stations with less variability in tree diameter and more shrubs. My study illustrates the significance of the Altamaha River bottomlands for the conservation of a diverse assemblage of breeding birds, including numerous Neotropical migratory species of regional conservation concern. My study also suggests that beyond allowing flooding and tree fall to occur naturally, management of mature Altamaha River bottomlands for diversity in the breeding bird community may be achieved with little active management. However, single-tree or group-selection harvests may be beneficial to a few important breeding Neotropical migratory bird species.

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