Semester of Graduation

Summer 2021

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

In the southeastern U.S., pine forests cover ~28 million ha and are most often used for commercial timber and hunting. Management practices used to reach desired vegetative conditions in these forests may simultaneously influence distributions of overwintering songbirds, including several grassland-nesting songbirds. From December to February of 2018 and 2019 and December of 2020, I surveyed longleaf (Pinus palustris) and loblolly pine (P. taeda) stands burned 0–7 years ago to examine the influence of pine management on grassland-nesting birds overwintering in central Louisiana. I used single-season occupancy and N-mixture models to examine occupancy and abundance of the grassland-nesting species I detected during my surveys in relation to stand type, years since burn, and site-scale vegetation conditions. I also used generalized linear models and indicator species analysis to examine the influence of stand type, years since burn, and site-scale vegetation conditions on overall bird species richness and to determine the indicator species for each treatment. Additionally, I used analysis of variance to compare vegetation across study sites and detection points for grassland-nesting songbirds in my treatments. I recorded 11,551 detections of 72 bird species at 32 study sites, including three grassland-nesting species. Bachman’s sparrow (Peucaea aestivalis) occupancy was greatest in longleaf stands, and sedge wren (Cistothorus stellaris) occupancy increased with decreasing canopy cover. Henslow’s sparrow (Centronyx henslowii) density decreased with increasing litter depth, Bachman’s sparrow density increased with increasing number of vegetation point contacts between 0–0.1 m, and sedge wren density increased with increasing herbaceous cover. I found bird species richness decreased with increasing canopy cover, and differences in vegetation used by species of conservation concern across study sites and detection points in longleaf pine burned 0–2 years before my surveys. My results indicated that shorter fire return intervals in pine forests can create understory vegetation structure and composition that supports a greater number of bird species and provides important habitat for grassland-nesting songbirds of conservation concern. Information gained from my study and additional research that identifies winter-habitat associations of grassland-nesting songbirds will help inform management to benefit these species during non-breeding periods and across the annual cycle.

Committee Chair

Long, Ashley M.

Available for download on Sunday, July 10, 2022

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