Document Type
Thesis
Date of Award
2026
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Ranjeet John
Abstract
Russian olive (Elaeagnus angustifolia; RO) is an invasive, nitrogen-fixing tree that has spread across riparian ecosystems in the western United States, potentially hindering native tree recruitment, reducing species richness, and impacting wildlife. RO has established within the Missouri National Recreational River (MNRR) in part due to modified flow regimes following dam construction. This study aimed to map the spread of RO using high-resolution National Agriculture Imagery Program (NAIP) imagery (2010, 2012, 2018, 2022) and evaluate the effects of the 2011 and 2019 floods on RO distributions in the Missouri National Recreational River (MNRR). RO cover in this area has expanded in recent decades, likely due to altered flow regimes from upstream dams. Previous studies in the MNRR estimated RO mortality between 65-90% in response to the 2011 flood, with little known about the impacts of the 2019 flood. A Convolutional Neural Network (CNN) model was trained using 2022 imagery, and object-based image analysis was then used to segment imagery and integrate the CNN predictions for classification, yielding an overall accuracy of 90.6% and a class-specific F1 score of 0.83 for RO. Applying the model to historical imagery revealed a 71% reduction in RO canopy cover following the 2011 flood and a 28% reduction following the 2019 flood. RO spatial configurations in 2018 resembled pre-flood spatial patterns, indicating that resprouting may have accelerated recovery. While frequent flooding may reduce RO establishment and spread, it will not eliminate it entirely, highlighting the importance of monitoring and management. The model developed in this study could be used to track RO patches and support land managers in detecting early establishment of RO, because once RO becomes widespread, it becomes difficult to eliminate.
Subject Categories
Biology
Keywords
Russian olive, Elaeagnus angustifolia, Missouri National Recreational River
Number of Pages
53
Publisher
University of South Dakota
Recommended Citation
Schild, Zachary, "Analyzing Changes in Russian Olive Distributions Along the Missouri River in Response to Flooding" (2026). Dissertations and Theses. 407.
https://red.library.usd.edu/diss-thesis/407