Date of Award
Great Lakes Institute for Environmental Research
Agricultural drains, Biodiversity, Drain management, Phragmites australis, Riparian vegetation
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This work is licensed under a Creative Commons Attribution 4.0 International License.
Agricultural drainage systems are important components of regional ecosystems and play key roles in ecosystem functioning. Biodiversity is a service provided by drains which is not fully understood in agriculturally dominated areas and is disrupted consistently by drain management, specifically in drains invaded by Phragmites australis. The objective of this thesis was to characterize the contribution of regional vegetational biodiversity provided by drainage systems, across sites representing a gradient of management frequencies. Drains were separated into management categories: Low (managed +5 years ago), Medium (managed every 3-5 years), or High (managed yearly). Plant abundance was measured and biodiversity indices (Species Richness, Simpson’s, and Shannon-Wiener) were compared across the management gradient. In total, 133 distinct plant species were reported across spring and late-summer growing season surveys. Plant identifications were confirmed by local experts using a structured expert elicitation protocol. A number of environmental variables were visualized using non-metric multi-dimensional scaling (NMDS), principal component analysis (PCA), and redundancy analysis (RDA). Community composition differed across management categories, with sites under high levels of management dominated by graminoid (grasses) species. Community composition varied significantly across management categories. Biodiversity indices differed significantly across management categories, with low management sites having higher levels of biodiversity. Environmental variables did not have a strong correlation with community composition, however RDA analyses found management intensity to be the only significant variable relating to community composition. This thesis provides the first known baseline of vegetational community composition for agricultural drains across Windsor Essex. Vegetational biodiversity was dampened by regular drain management and this insight will be useful in exploring the multifunctional roles of drains in supporting biodiversity and ecosystem functions locally and regionally.
Graham, Ryan Mackenzie, "The Characterization of Riparian Vegetation in Agriculture Drains Impacted by Phragmites australis and Drain Management: A Southwestern Ontario, Canada Case Study" (2023). Electronic Theses and Dissertations. 9102.