Date of Award

Spring 5-11-2026

Document Type

Undergraduate Honors Thesis

Degree Name

Bachelor of Arts in Environmental Studies

Department

Environmental and Ocean Sciences

Advisor

Dr. Sophie Taddeo

Abstract

Due to the threat of invasive species on wetland biodiversity, it is critical to assess factors driving their proliferation in wetlands. To address this growing need, this project analyzes relationships between non-native species and known anthropogenic disturbance types associated with increased biological invasions. Using the U.S. EPA’s 2021 National Wetland Condition Assessment, the relationship between non-native species (diversity, richness, and coverage) and surrounding land-use within 500, 1,000, and 3,000-meter buffers was evaluated. To explore patterns across larger spatial scales, mean non-native species diversity, richness, and coverage was calculated at the watershed level and compared to associated percentages of agricultural land and urban development. While weak, significant relationships between the proportion of high intensity development and native richness and diversity at the 1,000 and 3,000-meter scale emerged, as well as between proportions of intermediate disturbance and non-native richness and diversity. Spatial findings at the watershed scale were integrated into a weighted suitability model to identify optimal restoration sites for all watersheds intersecting with the state of California based upon habitat connectivity, disturbance proximity, and the location of major ports. Results suggest that changes to wetland plant composition are occurring in response to disturbance across landscapes and regional scales. These findings can inform future restoration efforts at multiple temporal and spatial scales by identifying high priority areas, as vegetation is a particularly strong indicator of wetland conditions. Through better understanding how plant diversity responds to landscape stressors, conservation and restoration practices may be better advised and supported.

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