Effects of Experimental Forest Management on Density and Nesting Success of Bird Species in Missouri Ozark Forests
A critical step in understanding the relationship between forest management and bird populations is conducting studies that employ rigorous experimental designs, relate forest management to avian demography, and explore relationships at expanded temporal and spatial scales. The Missouri Ozark Forest Ecosystem Project ( MOFEP ) is a long-term, large-scale manipulative experiment that is testing the effects of even-aged ( i.e., clearcutting ) and uneven-aged ( i.e., selection cutting ) forest management on a suite of response variables in Missouri oak-hickory forests. We report on the short-term effects of these management systems on the density and reproductive success of birds by evaluating 5 years of preharvest and 3 years of postharvest data from MOFEP. Densities of mature forest species declined 24–69% on the control ( i.e., no timber harvest ) sites during post-treatment years, confounding interpretation of treatment effects. Densities of both Kentucky Warblers ( Oporornis formosus ) and Worm-eating Warblers ( Helmitheros vermivorus ) increased in treatment sites relative to control sites. Conversely, even-aged management negatively affected Ovenbird ( Seiurus aurocapillus ) density. Treatment significantly and positively affected density of four of the six early successional species. Densities of Indigo Bunting ( Passerina cyanea ) and Yellow-breasted Chat ( Icteria virens ) were significantly higher in both even-aged and uneven-aged treatments, whereas densities of Prairie Warbler ( Dendroica discolor ) and White-eyed Vireo ( Vireo griseus ) were significantly higher in even-aged treatments than in the controls. Nest success rates averaged 29% for all species and did not change significantly from pre- to post-treatment years. Mature forest bird populations declined as trees were removed, but significant changes in nest predation and brood parasitism did not occur. In addition, openings associated with timber removal provided habitats for early successional species. We suggest that a mixed strategy of timber management may be necessary to support the full range of breeding birds in this region.
Document Type: Research Article
Affiliations: 1: Sam Noble Oklahoma Museum of Natural History , University of Oklahoma, 2401 Chautauqua Avenue, Norman, OK 73072–1029, U.S.A. 2: Division of Science and Math , Central Methodist College, Fayette, MO 65248, U.S.A. 3: Wildlife Research Section , Missouri Department of Conservation, Columbia, MO 65201, U.S.A. 4: Division of Biological Sciences , University of Missouri, Columbia, MO 65211, U.S.A.
Publication date: October 1, 2003