Search

Search Results

• 41. [Article] Agricultural Management Decisions Impact Isoprene Emission and Physiology of Arundo donax, an Emerging Bioenergy Crop

  Arundo donax (Giant Reed) is quickly being developed as a rapidly-growing, robust, and highly productive bioenergy crop, with large scale cultivation of this species planned for the Columbia River basin ...

  Citation × Citation Citation Abstract Copy Title: Agricultural Management Decisions Impact Isoprene Emission and Physiology of Arundo donax, an Emerging Bioenergy Crop Author: Maxfield, Jason Charles Year: 2014 Arundo donax (Giant Reed) is quickly being developed as a rapidly-growing, robust, and highly productive bioenergy crop, with large scale cultivation of this species planned for the Columbia River basin of the Pacific Northwest (USA). Despite its potential as a next generation biomass crop, relatively few studies have examined the physiological performance of A. donax under agricultural conditions. Unlike traditional crops, A. donax is known to be a high-emitter of the volatile compound isoprene, which may significantly impact regional air quality, but it has not been widely cultivated in North America and little is known about how this species will perform in the Pacific Northwest. Over two field seasons, we measured isoprene fluxes from A. donax plants in both greenhouse conditions and in an agricultural field setting under a variety of conditions and fertilizer treatments. We also measured several other attributes of A. donax productivity and leaf physiology including chlorophyll content, photosynthesis rate, stomatal conductance, specific leaf mass, water use efficiency and gas exchange. We found that A. donax physiologically performs well under cultivation in the Columbia River basin, but that it also emits isoprene at significantly higher rates than previous reports indicate. We also found that both isoprene emission and leaf physiology were highly affected by agricultural management decisions, including nitrogen and irrigation management. Our findings indicate that crop management strategies can be developed that simultaneously seek to minimize isoprene emission while maximizing biomass production in this newly emerging bioenergy crop. Title: Agricultural Management Decisions Impact Isoprene Emission and Physiology of Arundo donax, an Emerging Bioenergy Crop Author: Maxfield, Jason Charles Year: 2014 Arundo donax (Giant Reed) is quickly being developed as a rapidly-growing, robust, and highly productive bioenergy crop, with large scale cultivation of this species planned for the Columbia River basin of the Pacific Northwest (USA). Despite its potential as a next generation biomass crop, relatively few studies have examined the physiological performance of A. donax under agricultural conditions. Unlike traditional crops, A. donax is known to be a high-emitter of the volatile compound isoprene, which may significantly impact regional air quality, but it has not been widely cultivated in North America and little is known about how this species will perform in the Pacific Northwest. Over two field seasons, we measured isoprene fluxes from A. donax plants in both greenhouse conditions and in an agricultural field setting under a variety of conditions and fertilizer treatments. We also measured several other attributes of A. donax productivity and leaf physiology including chlorophyll content, photosynthesis rate, stomatal conductance, specific leaf mass, water use efficiency and gas exchange. We found that A. donax physiologically performs well under cultivation in the Columbia River basin, but that it also emits isoprene at significantly higher rates than previous reports indicate. We also found that both isoprene emission and leaf physiology were highly affected by agricultural management decisions, including nitrogen and irrigation management. Our findings indicate that crop management strategies can be developed that simultaneously seek to minimize isoprene emission while maximizing biomass production in this newly emerging bioenergy crop. Close

• 42. [Article] Long-term Ecological Research in Forest Park: Tracking Urban Impacts to Forest Structure and Productivity

  Current and historic land use practices as well as exposure to an urban environment can impact forest structure and function. Past and ongoing research in Forest Park, a large urban forest in Portland, ...

  Citation × Citation Citation Abstract Copy Title: Long-term Ecological Research in Forest Park: Tracking Urban Impacts to Forest Structure and Productivity Author: Addessi, Andrew, Dresner, Marion Year: 2017 Current and historic land use practices as well as exposure to an urban environment can impact forest structure and function. Past and ongoing research in Forest Park, a large urban forest in Portland, Oregon, suggests that mature Douglas-fir (Psuedotsuga meziesii) dominated conifer stands in the more urban end of the park are not developing certain late successional features. Notably, they lack a shade-tolerant conifer understory composed of western hemlock (Tsuga heterophylla) and western red-cedar (Thuja plicata). Here, I present three lines of investigation taken from several 1-hectare permanent long-term ecological research (LTER) plots in Forest Park. First, I investigated whether plot-level differences in the intensity of past-land use, namely clearcut logging and fire, has created legacy effect on soil health, as measured by soil organic matter, soil pH, and depth of organic horizon. Second, I present 5-year growth and mortality data to characterize productivity patterns in these plots. Last, I analyzed light detection and ranging (LiDAR) data covering Forest Park to determine if canopy structural features diverged across urban and rural sections of the park. Overall, the results indicate some legacy of soil impact to urban areas most effected by past intensive logging. However, forest productivity, mortality, and structural patterns were generally consistent with stand age, and did not show strong patterns related to urban proximity. These results indicate that the lack of shade tolerant species might be most limited by ground level impacts. These results help inform park managers that regeneration of late successional tree species may require active restoration practices that focus on establishing more optimal growing sites. Title: Long-term Ecological Research in Forest Park: Tracking Urban Impacts to Forest Structure and Productivity Author: Addessi, Andrew, Dresner, Marion Year: 2017 Current and historic land use practices as well as exposure to an urban environment can impact forest structure and function. Past and ongoing research in Forest Park, a large urban forest in Portland, Oregon, suggests that mature Douglas-fir (Psuedotsuga meziesii) dominated conifer stands in the more urban end of the park are not developing certain late successional features. Notably, they lack a shade-tolerant conifer understory composed of western hemlock (Tsuga heterophylla) and western red-cedar (Thuja plicata). Here, I present three lines of investigation taken from several 1-hectare permanent long-term ecological research (LTER) plots in Forest Park. First, I investigated whether plot-level differences in the intensity of past-land use, namely clearcut logging and fire, has created legacy effect on soil health, as measured by soil organic matter, soil pH, and depth of organic horizon. Second, I present 5-year growth and mortality data to characterize productivity patterns in these plots. Last, I analyzed light detection and ranging (LiDAR) data covering Forest Park to determine if canopy structural features diverged across urban and rural sections of the park. Overall, the results indicate some legacy of soil impact to urban areas most effected by past intensive logging. However, forest productivity, mortality, and structural patterns were generally consistent with stand age, and did not show strong patterns related to urban proximity. These results indicate that the lack of shade tolerant species might be most limited by ground level impacts. These results help inform park managers that regeneration of late successional tree species may require active restoration practices that focus on establishing more optimal growing sites. Close

• 43. [Article] SITE FIDELITY AND HOMING BEHAVIOR OF THE INTERTIDAL STICHAEIDAE, XIPHISTER ATROPURPUREUS (BLACK PRICKLEBACK)

  31 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 201...

  Citation × Citation Citation Abstract Copy Title: SITE FIDELITY AND HOMING BEHAVIOR OF THE INTERTIDAL STICHAEIDAE, XIPHISTER ATROPURPUREUS (BLACK PRICKLEBACK) Author: Nelson, Ashley Kim Year: 2014, 2013 31 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 2013. Title: SITE FIDELITY AND HOMING BEHAVIOR OF THE INTERTIDAL STICHAEIDAE, XIPHISTER ATROPURPUREUS (BLACK PRICKLEBACK) Author: Nelson, Ashley Kim Year: 2014, 2013 31 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 2013. Close

• 44. [Article] Prospectus for Future Research: Temperature Effects on Green Macroalgae

  Research on temperature change has received attention from scientists. Not only has temperature change attracted scientists who study the Earth’s weather and climate, but also those who study plants and ...

  Citation × Citation Citation Abstract Copy Title: Prospectus for Future Research: Temperature Effects on Green Macroalgae Author: Gonzalez Pelayo, Ana Year: 2016 Research on temperature change has received attention from scientists. Not only has temperature change attracted scientists who study the Earth’s weather and climate, but also those who study plants and animals on land and in oceans. The research being conducted looks at how these temperature changes affect the anatomy and physiology of organisms, but other research also studies how terrestrial and aquatic ecosystems have changed and the types of responses that have occurred as a result. For many years, research in terrestrial ecosystems has dominated research in aquatic ecosystems. Limited research has been conducted in aquatic ecosystems involving green macroalgae, which are primary producers and an essential part of these ecosystems. Within the last fifteen years, research regarding the effects of temperature change on green macroalgae has shown that temperature affects photosynthesis and biochemistry. Overall, photosynthesis is almost completely inhibited after sufficient exposure due to damage in Photosystem II. There is also a substantial change in the production of chemical molecules known as reactive oxygen species that caused physical damage to the algal cells as well as a change in structure for proteins that is essential for function. I reviewed the literature within the past fifteen years, regarding the effects of temperature on a variety of green macroalgae species. The results indicated that after sufficient exposure, the photosynthetic rate of macroalgae is reduced significantly and that the change in chemistry lead to alterations in the physiology of green macroalgae. In this thesis, I propose two possible directions for algae research that involves genetic sequencing of a model species to identify a possible temperature tolerance gene, as well as the potential use of green macroalgae in photobioreactors as a source of renewable energy. Title: Prospectus for Future Research: Temperature Effects on Green Macroalgae Author: Gonzalez Pelayo, Ana Year: 2016 Research on temperature change has received attention from scientists. Not only has temperature change attracted scientists who study the Earth’s weather and climate, but also those who study plants and animals on land and in oceans. The research being conducted looks at how these temperature changes affect the anatomy and physiology of organisms, but other research also studies how terrestrial and aquatic ecosystems have changed and the types of responses that have occurred as a result. For many years, research in terrestrial ecosystems has dominated research in aquatic ecosystems. Limited research has been conducted in aquatic ecosystems involving green macroalgae, which are primary producers and an essential part of these ecosystems. Within the last fifteen years, research regarding the effects of temperature change on green macroalgae has shown that temperature affects photosynthesis and biochemistry. Overall, photosynthesis is almost completely inhibited after sufficient exposure due to damage in Photosystem II. There is also a substantial change in the production of chemical molecules known as reactive oxygen species that caused physical damage to the algal cells as well as a change in structure for proteins that is essential for function. I reviewed the literature within the past fifteen years, regarding the effects of temperature on a variety of green macroalgae species. The results indicated that after sufficient exposure, the photosynthetic rate of macroalgae is reduced significantly and that the change in chemistry lead to alterations in the physiology of green macroalgae. In this thesis, I propose two possible directions for algae research that involves genetic sequencing of a model species to identify a possible temperature tolerance gene, as well as the potential use of green macroalgae in photobioreactors as a source of renewable energy. Close

• 45. [Article] The Importance of Urban Habitat Connectivity and Influence on Native Avian Species and Community Science

  In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project ...

  Citation × Citation Citation Abstract Copy Title: The Importance of Urban Habitat Connectivity and Influence on Native Avian Species and Community Science Author: Gulick, Kristen S. Year: 2017 In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to better understand how backyard habitat restoration might affect their habitat especially when in close proximity to a natural area. The goal of the project was to help better understand the beneficial effects of urban gardening using native plants and diverse vegetation structure as this relates to bird species richness, and to explore the importance of community scientist contributions. Although the sample size was small, no significant trends were found, but the involvement of community scientists indicated increased skill, depth of understanding, and increased motivation for all participating backyard habitat owners. More backyards are needed for future research and extension into lower-income neighborhoods would be very beneficial to increase awareness of urban habitat connectivity and the diversity seen in backyard environmental characteristics and yard owner backyard habitat knowledge. A larger sample size could reveal correlations and provide a greater significance in data findings for bird abundance and diversity. A logical extension of this project would be to investigate food-web effects, specifically avian prey species, and smaller green-spaces that are often present in urban neighborhoods in addition to the large green-spaces. Authors: Kristen S. Gulick, Marion Dresner, Nikkie West Presenter: Kristen S. Gulick Title: The Importance of Urban Habitat Connectivity and Influence on Native Avian Species and Community Science Author: Gulick, Kristen S. Year: 2017 In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to better understand how backyard habitat restoration might affect their habitat especially when in close proximity to a natural area. The goal of the project was to help better understand the beneficial effects of urban gardening using native plants and diverse vegetation structure as this relates to bird species richness, and to explore the importance of community scientist contributions. Although the sample size was small, no significant trends were found, but the involvement of community scientists indicated increased skill, depth of understanding, and increased motivation for all participating backyard habitat owners. More backyards are needed for future research and extension into lower-income neighborhoods would be very beneficial to increase awareness of urban habitat connectivity and the diversity seen in backyard environmental characteristics and yard owner backyard habitat knowledge. A larger sample size could reveal correlations and provide a greater significance in data findings for bird abundance and diversity. A logical extension of this project would be to investigate food-web effects, specifically avian prey species, and smaller green-spaces that are often present in urban neighborhoods in addition to the large green-spaces. Authors: Kristen S. Gulick, Marion Dresner, Nikkie West Presenter: Kristen S. Gulick Close

• 46. [Article] Community Science and the Ecological Merits of Backyard Habitat Patches and Adjacent Green-Spaces for Urban Avian Species

  In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project ...

  Citation × Citation Citation Abstract Copy Title: Community Science and the Ecological Merits of Backyard Habitat Patches and Adjacent Green-Spaces for Urban Avian Species Author: Gulick, Kristen S., West, Nikkie, Dresner, Marion Year: 2017 In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to better understand how backyard habitat restoration might affect their habitat especially when in close proximity to a natural area. The goal of the project was to help better understand the beneficial effects of urban gardening using native plants and diverse vegetation structure as this relates to bird species richness, and to explore the importance of community scientist contributions. Although the sample size was small, no significant trends were found, but the involvement of community scientists indicated increased skill, depth of understanding, and increased motivation for all participating backyard habitat owners. More backyards are needed for future research and extension into lower-income neighborhoods would be very beneficial to increase awareness of urban habitat connectivity and the diversity seen in backyard environmental characteristics and yard owner backyard habitat knowledge. A larger sample size could reveal correlations and provide a greater significance in data findings for bird abundance and diversity. A logical extension of this project would be to investigate food-web effects, specifically avian prey species, and smaller green-spaces that are often present in urban neighborhoods in addition to the large green-spaces. Title: Community Science and the Ecological Merits of Backyard Habitat Patches and Adjacent Green-Spaces for Urban Avian Species Author: Gulick, Kristen S., West, Nikkie, Dresner, Marion Year: 2017 In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to better understand how backyard habitat restoration might affect their habitat especially when in close proximity to a natural area. The goal of the project was to help better understand the beneficial effects of urban gardening using native plants and diverse vegetation structure as this relates to bird species richness, and to explore the importance of community scientist contributions. Although the sample size was small, no significant trends were found, but the involvement of community scientists indicated increased skill, depth of understanding, and increased motivation for all participating backyard habitat owners. More backyards are needed for future research and extension into lower-income neighborhoods would be very beneficial to increase awareness of urban habitat connectivity and the diversity seen in backyard environmental characteristics and yard owner backyard habitat knowledge. A larger sample size could reveal correlations and provide a greater significance in data findings for bird abundance and diversity. A logical extension of this project would be to investigate food-web effects, specifically avian prey species, and smaller green-spaces that are often present in urban neighborhoods in addition to the large green-spaces. Close

• 47. [Article] Investigating an adaptive explanation for nonprogressor immune responses to SIV

  62 pages. A thesis presented to the Department of Anthropology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring ...

  Citation × Citation Citation Abstract Copy Title: Investigating an adaptive explanation for nonprogressor immune responses to SIV Author: McVeety, Kelsie Year: 2015 62 pages. A thesis presented to the Department of Anthropology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2015. Title: Investigating an adaptive explanation for nonprogressor immune responses to SIV Author: McVeety, Kelsie Year: 2015 62 pages. A thesis presented to the Department of Anthropology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2015. Close

• 48. [Article] THE OLIGOCENE MARINE MOLLUSCAN FAUNA OF THE EUGENE FORMATION IN OREGON

  124 pages

  Citation × Citation Citation Abstract Copy Title: THE OLIGOCENE MARINE MOLLUSCAN FAUNA OF THE EUGENE FORMATION IN OREGON Author: STENTZ HICKMAN, CAROLE JEAN Year: 2016, 1969 124 pages Title: THE OLIGOCENE MARINE MOLLUSCAN FAUNA OF THE EUGENE FORMATION IN OREGON Author: STENTZ HICKMAN, CAROLE JEAN Year: 2016, 1969 124 pages Close

• 49. [Article] The Relationship between Plankton and Water Mass Properties in High Arctic (Svalbard) Fjords

  43 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 201...

  Citation × Citation Citation Abstract Copy Title: The Relationship between Plankton and Water Mass Properties in High Arctic (Svalbard) Fjords Author: Poje, Alexandra Merritt Year: 2017, 2016 43 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 2016 Title: The Relationship between Plankton and Water Mass Properties in High Arctic (Svalbard) Fjords Author: Poje, Alexandra Merritt Year: 2017, 2016 43 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 2016 Close

• 50. [Article] The Relationship between Plankton and Water Mass Properties in High Arctic (Svalbard) Fjords

  43 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 201...

  Citation × Citation Citation Abstract Copy Title: The Relationship between Plankton and Water Mass Properties in High Arctic (Svalbard) Fjords Author: Poje, Alexandra Year: 2017, 2016 43 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 2016. Title: The Relationship between Plankton and Water Mass Properties in High Arctic (Svalbard) Fjords Author: Poje, Alexandra Year: 2017, 2016 43 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Fall 2016. Close