The effects of prescribed surface fire on ground- and shrub-nesting nearctic migrants at Fork Ridge, Hoosier National Forest, 1996 and 1997

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Authors
Aquilani, Steven M.
Advisor
Morrell, Tom
Issue Date
1998
Keyword
Degree
Thesis (M.S.)
Department
Department of Biology
Other Identifiers
Abstract

During autumn 1993, the U. S. Forest Service began implementing a program of prescribed surface fire in the Fork Ridge region of Hoosier National Forest. To determine the effects of the prescribed surface fire on ground- and shrub-nesting nearctic migrants, I conducted vegetation structure sampling, bird abundance surveys, and nest searches during the 1996 and 1997 breeding seasons. The prescribed surface fire drastically reduced understory vegetative cover from 0.0 to 2.5 m above ground and the density of live stems < 5.0 cm dbh. Herbaceous cover < 0.5 m tall in the burned site returned to levels similar to the unburned site within 2 years of the burn.Prescribed burning had little effect on overall avian species diversity, but altered the community composition. In 1996, there were 12 species present in the unburned site which were absent in the burned site and 9 species present in the burned site which were absent in the unburned site. In 1997, there were 9 species present in the unburned site which were absent in the burned site and 7 species present in the burned site which were absent in the unburned site. As a guild, ground- and shrub-nesting nearctic migrants and residents were less abundant in the burned site compared to the unburned site. Conversely, species such as Indigo Buntings (Passerina cyanea) and White-breasted Nuthatches (Sitter carolinensis) were more abundant in the burned site.Nests in the burned site had a 25% success rate, whereas nests in the unburned site had a 44% success rate. Nest parasitism did not differ between the burned site (1.2 cowbird eggs/nest) and unburned site (0.9 cowbird eggs/nest). Worm-eating Warblers (Helmitheros vermivorus) were the only ground- and shrunb-nesting nearctic migrant found in the burned site. Worm-eating Warbler nests in the burned site were characterized as having greater understory cover than surrounding burned areas. My results suggest that prescribed surface fires in Fork Ridge may be negatively impacting some ground- and shrub-nesting migrants by altering nesting habitat.

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