Master of Science (MS)
Forestry, Wildlife, and Fisheries
Decline of northern bobwhite (Colinus virginianus) populations during the past 30 years in southern portions of their range has increased efforts to improve habitat quality by integration of wildlife and forest management. Prescribed burns and herbicides have potential to benefit bobwhites, vegetation, invertebrates, and small mammal communities in pine-dominated systems. This study was conducted at 700-hectare Louisiana State University Idlewild Research Station of LSU's Agricultural Center in East Feliciana Parish. The experiment was conducted on 3, 10.12-hectare, 75 to 85 year-old, over-mature, uneven-aged pine stands on hilltops and sloping terrain. Experimental design included vegetation, invertebrate, and small mammal response to 3 treatments of 2 types of selective herbicide (imazapyr, imazapyr + glyphosate) and a control applied after an initial prescribed burn. Each stand served as whole plots and treatments as subplots within a split-plot arrangement. Treatments were randomly assigned and replicated across 3 stands. Herbicide treatments were more effective at improving vegetational structure for brood-rearing and nesting bobwhites. Plant and invertebrate species diversity declined on herbicide treatments during the first year, but increased on imazapyr plots during the second year. Bobwhite food plants increased on imazapyr plots for the first year and were greater on both herbicide treatments the second year. Herbicides reduced sweetgum but neither negatively affected hard mast producing species > 10 cm dbh. High overstory canopy closure and drought conditions may have negatively affected vegetation response. Herbicides did not produce bare ground percentages preferred by bobwhites. Prescribed burn alone created and maintained escape cover more suitable for bobwhites. Overall, imazapyr provided greater benefits to bobwhite, retained floristic species diversity, and greatly improved invertebrate diversity. Small mammal abundance increased on herbicide treatments presumably because of changes in vegetational characteristics and communities, and increased plant and invertebrate diversity on imazapyr treatments. Additionally, Peromyscus species was most common mammal trapped on all plots. Future research should evaluate vegetative response to herbicides under variable canopy conditions and different imazapyr application rates. We recommend managers target areas where prescribed burns are not possible and apply imazapyr strategically to create diverse, patchy habitat.
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Jones, Judy Diane James, "Effects of selective herbicide application on vegetation and invertebrates for northern bobwhite, and small mammal communities within managed pine forests" (2003). LSU Master's Theses. 595.
Michael J. Chamberlain