Graduate Thesis Or Dissertation


Exploring urban parks: plant communities, visitor experiences, and manager perspectives in Portland, Oregon Public Deposited

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  • Urban parks are biodiversity hotspots within cities and have the potential to provide a range of socio-cultural benefits for people, but may not always meet the needs and desires of park visitors. A variety of land use practices and environmental factors affect urban park biodiversity and vegetation structure, composition, and ecological function, but more studies are needed to compare plant taxonomic composition, biodiversity patterns, and species traits across different types of urban green spaces. Additionally, there is a lack of research that explores park user experiences, vegetation perceptions, and accessibility issues in a range of urban park types interspersed throughout Portland using qualitative methods to observe and interview visitors on-site. More research is also needed that focuses on interviewing park managers about their perspectives on park benefits and management. The findings of my interdisciplinary dissertation may assist managers in their aims to achieve various ecological goals, as well as meet the needs and desires of park visitors within increasingly developed urban areas. The purpose of this research is three-fold, and includes examining: 1) The relationships between plant community composition, biodiversity patterns, environmental variables, and species traits in a range of urban parks in Portland, Oregon; 2) how the vegetation in these urban parks currently meets the needs and desires of visitors; and 3) how park managers currently manage vegetation in the parks to meet the needs and desires of visitors. We used a stratified random sampling design to select 15 urban parks of different types based on use, which included natural-passive use parks, recreational-active use parks, and multi-use parks. Multivariate analyses were used to explore plant composition data and associations. One-way analysis of variance was used to test hypotheses about variables associated with diversity. Significant differences in plant species richness and biodiversity indices were found between different park types. More native species were found in natural-passive use parks than other park types, more non-native species were found in multi-use parks than other park types, and more invasive species were found in natural passive-use parks than in recreational-active use parks. Attributes such as natural-passive use park type, wetland habitat, steep slopes, native species origin, non-native species origin, and vine and tree plant forms were most strongly correlated with the non-metric multidimensional scaling ordination, indicating that they exert the strongest influence on species abundance and distribution. These findings may assist managers in their aims to promote native species cover, reduce invasive species presence, or achieve additional management goals. For the second research question, I used qualitative research methods, including observation and semi-structured interviews, with 43 park visitors in the same 15 urban parks. Vegetation was often related to the reasons why people visited parks, which sometimes varied based on park type. Plants influenced how accessible the park was to some participants, including sufficient maintenance along trails/paths, shade, and/or open space. Across park types, visitors discussed trees, plant size, colors, and diversity as their favorite aspects of the plants. Trees were especially important to recreational-active use and multi-use park visitors who commented on their size and shade. Plant diversity appeared to be more important to natural-passive use and multi-use park visitors than those of recreational-active use parks. While the plants met the preferences of many visitors, more than half of them recommended changes. The recreational-active use and multi-use parks visitors wanted more colorful vegetation, flowers, middle-growth/shrubs, and improved placement of plants, while visitors of natural-passive use parks wanted removal of invasive and/or harmful plants. Overall, the participant demographics were relatively similar to Portland, but differed in terms of park type (e.g., fewer women and racial/ethnic minority individuals in natural-passive use parks), which implied that the range of potential socio-cultural benefits of parks may not be shared equitably. Managers should consider these findings to improve urban parks and vegetation planning and maintenance. Management actions are needed to better integrate plant preferences into park design and improve accessibility for women, ethnic/racial minorities, and individuals with disabilities. For the third research question, I conducted a total of 21 semi-structured interviews with managers of the same 15 parks. I also used a mixed methods approach to evaluate the manager interviews alongside the visitor interviews and quantitative plant community composition data collected at the parks. Non-metric multidimensional scaling ordinations were created to evaluate perspectives of plant management that were most strongly correlated with different urban parks. The managers’ favorite aspects of plant management were related to maintenance (e.g., weed/invasive management) across park types and ecosystem management in natural-passive use parks. Most managers indicated they would not make changes to plant management, but others discussed improving maintenance, increasing staffing, adding plants, updating infrastructure, and improving species selection. The ways in which managers perceived how visitors interacted with the vegetation and visitor comments influenced many plant choices and/or design such as eliminating hiding/camping places, improving aesthetics, selecting hearty plants to withstand trampling, and removing hazardous plants. However, not all visitor feedback from previous interviews was fully represented in the park visitor comments provided to managers, which implies that managers should solicit more feedback. Managers also described limitations such as funding and budget, staff resources, and unfavorable visitor behaviors that prevented them from managing in the ways they might prefer. There are opportunities to meet both the needs of managers and visitors by continuing to manage trails/paths in natural-passive use parks, removing weeds/invasive plants in all park types, and selecting a diversity of plants for recreational-active use and multi-use parks that have more color and flowers, but are also more climate-adapted, disease-resistant, drought-tolerant, and/or provide habitat for pollinators. Future research should investigate how manager and visitor preferences can be better integrated to maximize ecosystem services and benefits for both people and the environment. Ultimately, it is important to increase communication and collaboration between government agencies, non-profit organizations, and community members, as well as continue to invest in the many social and ecological benefits of urban parks.
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  • Talal, M.L. 2019. Exploring urban parks: plant communities, visitor experiences, and manager perspectives in Portland, Oregon. Ph.D. Dissertation, Oregon State University
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  • Ongoing Research
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  • 2019-05-30 to 2019-12-30



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