Document Type
Dissertation
Date of Award
2026
Degree Name
Doctor of Philosophy (PhD)
Department
Biology
First Advisor
David L Swanson
Abstract
Riparian ecosystems provide habitat for birds throughout their annual cycle, yet flow regulation along major rivers like the Missouri River has reduced early successional riparian forests. Following historic flooding in 2011, set-aside areas within the Missouri National Recreational River (MNRR) were established to allow natural riparian vegetation succession on newly created sandbars. I evaluated the value of these early successional forests for birds over three breeding seasons (2018–2020) and four migration periods (2020–2021). During migration, standardized point counts documented 7,462 individual birds representing 114 species across 828 surveys. Avian diversity was positively correlated with vertical habitat complexity, with the canopy layer particularly important in multi-predictor models. Early successional forests shared considerable species overlap with mature riparian forests (65%) and grasslands (63%) during migration but differed from anthropogenic woodlots (36%) because closed-canopy woodlots lacked the dense understory required by ground-foraging migrants such as sparrows. During the breeding season, point-count surveys across seven early successional sites documented 58 species, dominated by early successional habitat associates and ground-foraging and foliage-gleaning guilds. These sites also supported mature forest species, underscoring the biodiversity value of successional heterogeneity. To assess habitat quality provided by early successional riparian forests for migratory stopover, I measured plasma metabolite profiles (triglycerides and β-hydroxybutyrate) in 94 migrating birds captured in fall 2020–2021 at one of the study sites. Average metabolite concentrations were consistent with high-quality habitats and comparable to regional woodlots and mature forests, suggesting that early successional riparian habitats provide comparable refueling opportunities to these other habitats. Nest monitoring during the breeding season showed that reproductive success for several common species was comparable to values reported in other studies. Nest-site selection favored microhabitats with dense shrub cover, particularly of Russian olive. Vegetation structure, however, did not generally predict nest survival in species-specific models. Collectively, these findings demonstrate that early successional riparian forests provided important habitat across multiple stages of the avian annual cycle for multiple bird species. Management strategies within the MNRR should prioritize maintaining successional heterogeneity and dense shrub cover to maximize biodiversity and habitat quality for migratory and breeding landbirds.
Subject Categories
Biology
Keywords
Avian, biodiversity, early successional forests, Missouri National Recreational River, Riparian, successional heterogeneity
Number of Pages
237
Publisher
University of South Dakota
Recommended Citation
NEFAS, STEPHANIE, "AVIAN USE OF EARLY SUCCESSIONAL RIPARIAN FOREST ALONG THE MISSOURI RIVER: WHAT DO WE LOSE BY MANAGING FOR PLOVERS AND TERNS?" (2026). Dissertations and Theses. 442.
https://red.library.usd.edu/diss-thesis/442