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• 1. [Article] Commercial Wind Energy Projects in the Columbia Basin, Oregon

  Abstract -- This map depicts existing or potential project boundaries for commercial wind energy projects in or around the Columbia Basin

  Citation × Citation Citation Abstract Copy Title: Commercial Wind Energy Projects in the Columbia Basin, Oregon Abstract -- This map depicts existing or potential project boundaries for commercial wind energy projects in or around the Columbia Basin Title: Commercial Wind Energy Projects in the Columbia Basin, Oregon Abstract -- This map depicts existing or potential project boundaries for commercial wind energy projects in or around the Columbia Basin Close

• 2. [Article] South Santiam Watershed Assessment

  Abstract -- The South Santiam River drains approximately 1,040 square miles and is a primary tributary to the Willamette River. The South Santiam River watershed is situated in the Western Cascades and ...

  Citation × Citation Citation Abstract Copy Title: South Santiam Watershed Assessment Abstract -- The South Santiam River drains approximately 1,040 square miles and is a primary tributary to the Willamette River. The South Santiam River watershed is situated in the Western Cascades and flows into the Willamette Valley. The River runs approximately from east to west, with steep mountainous terrain comprising the eastern 80% of the watershed. The western 20% of the watershed leading to the Santiam River and ultimately the Willamette River, is comprised of a floodplain dominated by grass seed farming and urban/rural development. The basin ranges in elevation from 220 feet to approximately 5,721 feet. The South Santiam watershed was divided into an upper section (Headwaters, Quartzville, Middle Santiam and Foster watersheds) and a lower section (Lower South Santiam, Crabtree, Thomas, and Wiley subwatersheds) due to ecological differences such as ecoregion, management, and elevation. The assessment was conducted in six parts including Channel Habitat Typing, Channel Modification, Riparian, Water Use and Hydrology, Fisheries, and Water Quality. Following is a summary of results from each of the sections. Title: South Santiam Watershed Assessment Abstract -- The South Santiam River drains approximately 1,040 square miles and is a primary tributary to the Willamette River. The South Santiam River watershed is situated in the Western Cascades and flows into the Willamette Valley. The River runs approximately from east to west, with steep mountainous terrain comprising the eastern 80% of the watershed. The western 20% of the watershed leading to the Santiam River and ultimately the Willamette River, is comprised of a floodplain dominated by grass seed farming and urban/rural development. The basin ranges in elevation from 220 feet to approximately 5,721 feet. The South Santiam watershed was divided into an upper section (Headwaters, Quartzville, Middle Santiam and Foster watersheds) and a lower section (Lower South Santiam, Crabtree, Thomas, and Wiley subwatersheds) due to ecological differences such as ecoregion, management, and elevation. The assessment was conducted in six parts including Channel Habitat Typing, Channel Modification, Riparian, Water Use and Hydrology, Fisheries, and Water Quality. Following is a summary of results from each of the sections. Close

• 3. [Article] Lower Tillamook Bay Watershed Plan and Environmental Assessment

  Abstract -- This document describes a plan to improve water quality and fishery habitat within the Lower Tillamook Bay Watershed while improving the economic sustainability of the dairy and livestock industry. ...

  Citation × Citation Citation Abstract Copy Title: Lower Tillamook Bay Watershed Plan and Environmental Assessment Abstract -- This document describes a plan to improve water quality and fishery habitat within the Lower Tillamook Bay Watershed while improving the economic sustainability of the dairy and livestock industry. This plan will help the agricultural community meet the requirements under the Clean Water Act and the Endangered Species Act. The financial and technical assistance provided will offer the agricultural community the opportunity to accelerate efforts already underway through the Tillamook Bay National Estuary Study and other state and local programs (Oregon Plan, SB1010 plans, etc.). Proposed is the development and implementation of conservation plans on approximately 60 dairies, 22 heifer replacement operations and 34 other livestock operations. Plans will address resource concerns on farm headquarters, pasture and haylands, riparian areas and wetlands. Title: Lower Tillamook Bay Watershed Plan and Environmental Assessment Abstract -- This document describes a plan to improve water quality and fishery habitat within the Lower Tillamook Bay Watershed while improving the economic sustainability of the dairy and livestock industry. This plan will help the agricultural community meet the requirements under the Clean Water Act and the Endangered Species Act. The financial and technical assistance provided will offer the agricultural community the opportunity to accelerate efforts already underway through the Tillamook Bay National Estuary Study and other state and local programs (Oregon Plan, SB1010 plans, etc.). Proposed is the development and implementation of conservation plans on approximately 60 dairies, 22 heifer replacement operations and 34 other livestock operations. Plans will address resource concerns on farm headquarters, pasture and haylands, riparian areas and wetlands. Close

• 4. [Article] Commercial Wind Energy Projects in Oregon

  Abstract -- This map depicts existing or potential project boundaries for commercial wind energy projects within the state of Oregon

  Citation × Citation Citation Abstract Copy Title: Commercial Wind Energy Projects in Oregon Abstract -- This map depicts existing or potential project boundaries for commercial wind energy projects within the state of Oregon Title: Commercial Wind Energy Projects in Oregon Abstract -- This map depicts existing or potential project boundaries for commercial wind energy projects within the state of Oregon Close

• 5. [Article] Little Walla Walla River Assessment and Initial Action Plan (2010)

  Abstract -- The Little Walla Walla River and Spring Branch system is an anomaly when compared to most river systems. This non-linear combination of distributaries and an alluvial fan of spring fed creeks ...

  Citation × Citation Citation Abstract Copy Title: Little Walla Walla River Assessment and Initial Action Plan (2010) Abstract -- The Little Walla Walla River and Spring Branch system is an anomaly when compared to most river systems. This non-linear combination of distributaries and an alluvial fan of spring fed creeks is treated by various state agencies and the local community as either a water conveyance network or natural stream, depending on the location being considered, or the time of year. This conundrum needs to be described and evaluated so that a coordinated approach can be developed and implemented to improve these unusual streams and the farms, fish, and wildlife that depend on them. This assessment consolidates information on the Little Walla Walla River and springs area with regards to historic and current flows, water use, land use, fish presence, habitat conditions, fish passage barriers, and water quality. This can then be utilized in developing a plan that aim to improve and preserve the environmental and economic health of this stream network, and to better define management and enhancement options. An Initial Action Plan of Goals and Actions is put forward as a discussion framework. Some of these actions are just conceptual, others are ongoing, but can be expanded to a greater scale. Title: Little Walla Walla River Assessment and Initial Action Plan (2010) Abstract -- The Little Walla Walla River and Spring Branch system is an anomaly when compared to most river systems. This non-linear combination of distributaries and an alluvial fan of spring fed creeks is treated by various state agencies and the local community as either a water conveyance network or natural stream, depending on the location being considered, or the time of year. This conundrum needs to be described and evaluated so that a coordinated approach can be developed and implemented to improve these unusual streams and the farms, fish, and wildlife that depend on them. This assessment consolidates information on the Little Walla Walla River and springs area with regards to historic and current flows, water use, land use, fish presence, habitat conditions, fish passage barriers, and water quality. This can then be utilized in developing a plan that aim to improve and preserve the environmental and economic health of this stream network, and to better define management and enhancement options. An Initial Action Plan of Goals and Actions is put forward as a discussion framework. Some of these actions are just conceptual, others are ongoing, but can be expanded to a greater scale. Close

• 6. [Article] Neacoxie Watershed

  Abstract -- Previously, little information was known about the ecology or the condition of native habitats in the Neacoxie sub-watershed that drains from the city of Warrenton into the north section of ...

  Citation × Citation Citation Abstract Copy Title: Neacoxie Watershed Abstract -- Previously, little information was known about the ecology or the condition of native habitats in the Neacoxie sub-watershed that drains from the city of Warrenton into the north section of the Necanicum Estuary in the city of Seaside. In 2002, the Necanicum Watershed Council completed an assessment for the Necanicum River watershed, but with major knowledge gaps for the Neacoxie watershed, which includes the Neacoxie Creek corridor and the Clatsop Plains. In order for the North Coast Land Conservancy (NCLC) and other land managers to develop stewardship priorities and to make informed decisions about land management actions in this region, additional information was required. Together with the Necanicum Watershed Council and the North Coast Watershed Association, NCLC secured funding to conduct habitat inventories of the Neacoxie watershed. The Neacoxie Watershed Assessment summarizes the results of terrestrial plant transects and aquatic plant surveys completed in the summer of 2011 on ten properties owned by the North Coast Land Conservancy (NCLC) in the Neacoxie Creek watershed (please refer to Appendices A & B). Habitat types include stabilized sand dunes dominated by coastal prairie habitat, interdunal wetland swales and lakes, upland Sitka spruce forest, and forested wetlands. Percent composition of each plant community type observed was calculated. Invasive non-native plant species were recorded. Surveys were also conducted for both native and non-native plants in four water bodies owned by NCLC or adjacent to land trust properties. The plant community data that were collected will be used to evaluate baseline ecological conditions in the Neacoxie watershed. Plant communities can be used as indicators of long-term tidal and hydrologic conditions as well as the ecological health of the landscape. Repeated measurements can be used to assess community changes over time and to assess how plant community composition compares to that described for natural conditions. This information will assist the land trust in making science-based stewardship decisions on its properties, and can be used by other landowners to better understand changes occurring in plant communities in similar habitats on their properties as a result of human disturbance (e.g., land development, farming, grazing) and invasion by non-native plants. Title: Neacoxie Watershed Abstract -- Previously, little information was known about the ecology or the condition of native habitats in the Neacoxie sub-watershed that drains from the city of Warrenton into the north section of the Necanicum Estuary in the city of Seaside. In 2002, the Necanicum Watershed Council completed an assessment for the Necanicum River watershed, but with major knowledge gaps for the Neacoxie watershed, which includes the Neacoxie Creek corridor and the Clatsop Plains. In order for the North Coast Land Conservancy (NCLC) and other land managers to develop stewardship priorities and to make informed decisions about land management actions in this region, additional information was required. Together with the Necanicum Watershed Council and the North Coast Watershed Association, NCLC secured funding to conduct habitat inventories of the Neacoxie watershed. The Neacoxie Watershed Assessment summarizes the results of terrestrial plant transects and aquatic plant surveys completed in the summer of 2011 on ten properties owned by the North Coast Land Conservancy (NCLC) in the Neacoxie Creek watershed (please refer to Appendices A & B). Habitat types include stabilized sand dunes dominated by coastal prairie habitat, interdunal wetland swales and lakes, upland Sitka spruce forest, and forested wetlands. Percent composition of each plant community type observed was calculated. Invasive non-native plant species were recorded. Surveys were also conducted for both native and non-native plants in four water bodies owned by NCLC or adjacent to land trust properties. The plant community data that were collected will be used to evaluate baseline ecological conditions in the Neacoxie watershed. Plant communities can be used as indicators of long-term tidal and hydrologic conditions as well as the ecological health of the landscape. Repeated measurements can be used to assess community changes over time and to assess how plant community composition compares to that described for natural conditions. This information will assist the land trust in making science-based stewardship decisions on its properties, and can be used by other landowners to better understand changes occurring in plant communities in similar habitats on their properties as a result of human disturbance (e.g., land development, farming, grazing) and invasion by non-native plants. Close

• 7. [Article] A gold dream in the Blue Mountains : a study of the Chinese immigrants in the John Day area, Oregon, 1870-1910

  More than one hundred years have passed since the Chinese laborers first landed in this country in the mid-nineteenth century. Yet their history remains cloudy. This phenomenon is quite understandable ...

  Citation × Citation Citation Abstract Copy Title: A gold dream in the Blue Mountains : a study of the Chinese immigrants in the John Day area, Oregon, 1870-1910 Author: Chen, Chia-lin Year: 1972 More than one hundred years have passed since the Chinese laborers first landed in this country in the mid-nineteenth century. Yet their history remains cloudy. This phenomenon is quite understandable if one considers the facts that most of the laborers were illiterate, did not have the ability, and never intended, to speak for themselves. It is true that many scholarly works have been published, but few were written by Chinese historians. As a matter of fact, Chinese scholars are unaware that a small number of their countrymen played a strange, pitiful role in American history. The published works reflect the viewpoint of only American observers. The labor of the Chinese workers was indispensable to the development of the frontier West at a time when resources were abundant and labor hands were few. So much work had to be done building railroads and dams, digging mines, clearing farm lands, canning salmon, etc. And the Chinese were welcomed to every line of manual work. There was a time when nearly every family at Astoria of Oregon and Olympia of Washington hired a Chinese as servant, as some writers claim. When the great number of whites moved in from the east, along with them came the floating laborers and the European immigrants, as well as the labor union. Conditions changed rapidly, the Chinese found themselves not only excluded from all employment, but persecuted everywhere. California was the state which first utilized Chinese labor and first expelled it. This unfavorable circumstance forced the Chinese to flee from California to other states. The purpose of this paper is not to give an account of how the Chinese were maltreated in a country known as a free, equal land opened widely to the whole world, but rather tries to find out how they survived, what were their daily problems, sorrows, and happiness, if any, and what were their inner feelings, their attitudes toward the white hosts. In short, the paper is written in an attempt to reconstruct their life in an alien land. In addition, the paper tries to answer the question why this oriental group appeared so peculiar in their behavior, as some whites commented, that they were both condemned and contemned. One of the crucial problems facing the researcher in the field of early Chinese immigration history is the lack of original materials. This is the common defects in all the published works on this subject. Fortunately for the author, by an unique chance, he was able to study numerous objects left in a Chinese grocery store, the Kam Wah Chung Co. at John Day--a small town once a busy mining area in Eastern Oregon. The pioneer artifacts in this town are disappearing, though the gravels of the old gold placers are still visible along the hillsides and canyons. But the queer old building of the Chinese store is still standing stubbornly as it did one hundred years ago, on a road called Canton Street So many objects were left in the building that the city of John Day is endeavoring to open it as a museum. From a historical point of view, many of these objects are very valuable. Among them are a great number of letters. Some were sent to the laborers from their families, in care of that building. Others were from the laborers to their homes, and for some unknown reason had not been sent to China. They are unique and of special importance to this paper. Perhaps nowhere else in the United States, or in War-torn China, can one find such a number of first hand records about the early Chinese in this country. Although few significant events, romantic affairs, or anything exciting can be expected of them, still, one can reconstruct a plain sketch of their life from these materials. The paper, though it only presents a small picture of the Chinese group in Eastern Oregon, is aimed to serve, hopefully, as a footnote leading to an understanding of how the early Chinese immigrants once lived in the Pacific Northwest. Title: A gold dream in the Blue Mountains : a study of the Chinese immigrants in the John Day area, Oregon, 1870-1910 Author: Chen, Chia-lin Year: 1972 More than one hundred years have passed since the Chinese laborers first landed in this country in the mid-nineteenth century. Yet their history remains cloudy. This phenomenon is quite understandable if one considers the facts that most of the laborers were illiterate, did not have the ability, and never intended, to speak for themselves. It is true that many scholarly works have been published, but few were written by Chinese historians. As a matter of fact, Chinese scholars are unaware that a small number of their countrymen played a strange, pitiful role in American history. The published works reflect the viewpoint of only American observers. The labor of the Chinese workers was indispensable to the development of the frontier West at a time when resources were abundant and labor hands were few. So much work had to be done building railroads and dams, digging mines, clearing farm lands, canning salmon, etc. And the Chinese were welcomed to every line of manual work. There was a time when nearly every family at Astoria of Oregon and Olympia of Washington hired a Chinese as servant, as some writers claim. When the great number of whites moved in from the east, along with them came the floating laborers and the European immigrants, as well as the labor union. Conditions changed rapidly, the Chinese found themselves not only excluded from all employment, but persecuted everywhere. California was the state which first utilized Chinese labor and first expelled it. This unfavorable circumstance forced the Chinese to flee from California to other states. The purpose of this paper is not to give an account of how the Chinese were maltreated in a country known as a free, equal land opened widely to the whole world, but rather tries to find out how they survived, what were their daily problems, sorrows, and happiness, if any, and what were their inner feelings, their attitudes toward the white hosts. In short, the paper is written in an attempt to reconstruct their life in an alien land. In addition, the paper tries to answer the question why this oriental group appeared so peculiar in their behavior, as some whites commented, that they were both condemned and contemned. One of the crucial problems facing the researcher in the field of early Chinese immigration history is the lack of original materials. This is the common defects in all the published works on this subject. Fortunately for the author, by an unique chance, he was able to study numerous objects left in a Chinese grocery store, the Kam Wah Chung Co. at John Day--a small town once a busy mining area in Eastern Oregon. The pioneer artifacts in this town are disappearing, though the gravels of the old gold placers are still visible along the hillsides and canyons. But the queer old building of the Chinese store is still standing stubbornly as it did one hundred years ago, on a road called Canton Street So many objects were left in the building that the city of John Day is endeavoring to open it as a museum. From a historical point of view, many of these objects are very valuable. Among them are a great number of letters. Some were sent to the laborers from their families, in care of that building. Others were from the laborers to their homes, and for some unknown reason had not been sent to China. They are unique and of special importance to this paper. Perhaps nowhere else in the United States, or in War-torn China, can one find such a number of first hand records about the early Chinese in this country. Although few significant events, romantic affairs, or anything exciting can be expected of them, still, one can reconstruct a plain sketch of their life from these materials. The paper, though it only presents a small picture of the Chinese group in Eastern Oregon, is aimed to serve, hopefully, as a footnote leading to an understanding of how the early Chinese immigrants once lived in the Pacific Northwest. Close

• 8. [Article] Indians and Criminal Justice in Early Oregon, 1842-1859

  Indian-white relations in early Oregon are often viewed in terms of warfare and treatymaking, but these are only the most obvious aspects of a larger struggle to resolve cultural conflicts, settle land ...

  Citation × Citation Citation Abstract Copy Title: Indians and Criminal Justice in Early Oregon, 1842-1859 Author: Ferrell, John Samuel Year: 1973 Indian-white relations in early Oregon are often viewed in terms of warfare and treatymaking, but these are only the most obvious aspects of a larger struggle to resolve cultural conflicts, settle land disputes, and establish order in a new territory. Additional understanding of both white attitudes toward Indians and of Indian exasperation with the settlers may be gained from a study of how criminal justice applied to the red man during the turbulent pre-reservation era. Prior to the coming of America settlers, Oregon Indians knew the justice of the Hudson's Bay Company. In dealing with personas accused of harming HBC personnel or property, Dr. John McLoughlin acted with firmness and persistence while taking cognizance of the Indian's own ideas of just treatment, The American leaders of later years sometimes imitated McLoughlin's firmness but failed to recognize the importance of Indian tradition. Dr. Elijah White, after bring appointed the first U.S. Indian agent for Oregon in 1842, presented the natives with a law code which largely ignored their own traditions and confused them by making major offenses of what had formerly been viewed as minor infractions. Dr. White assured his charges that the new law code came from God and was recognized by all civilized nations. A similar smugness was apparent in later leaders who were convinced that the court proceedings against Indian troublemakers could not help but make a deep and beneficial impression on the defendants' fellow tribesman. Such assurance sometimes blinded the whites to inequities in their application of justice to Indian-white disputes and this blindness contributed to friction between the races. Criminal justice for Indians was a more complex matter during Oregon's territorial period than it had been during the HBC era. To the Indians, the British had been trading partners, but the Americans were dispossessors. A sizable influx of settlers preceded the signing of the Indian treaties, and the presence of two divergent cultures on the same disputed ground made necessary some means of dealing with the disagreements which inevitably arose. But civil officials, army officers, judges, and Indian agents were still working out their respective spheres of influence while new settlers might be many miles away from any hands. The belief expressed by leading figures in the army and the Indian Bureau that whites were to blame for outbreaks of violence did not encourage irate settlers or miners to rely on these agencies to settle disputes with Indians, and citizens' courts, minors' committees, or indiscriminate reprisals were often only forms of "justice" employed. Indians noted the infrequencies of prosecution for whites who committed crimes against them and complained that the whites had one set of laws for themselves and another for the red man, Adverse public opinion worked against the efforts of Indian superintendent Joel Palmer to correct this grievance, and lawyers sometimes questioned whether Indian were, in fact, "persons" or whether their mistreatment could constitute a crime. Even Dick Johnson, a successful Indian farmer who abandoned his native culture and won the support of Palmer and of Jesse Applegate in his efforts to model his life on white men's ideals, had so little legal identity that his suspected murderers were not tried and one of them was allowed to take his farm. Segregation of land and of peoples was the distraction in which both the law and public opinion pointed in Oregon Territory. Consciously and unconsciously, whites encouraged Indians to accept a reservation solution to the problems generated by land-hunger and culture clash, and among these problems legal discrimination and vigilante justice figured prominently. Hatred of the Indians among many of the settlers contributed substantially to distortion and non-application of criminal justice, but even with favorable public opinion, as in the case of Dick Johnson, the law itself was insufficient for an Indian who did not remove himself from white society and accept the treaty protections of the reservation. Title: Indians and Criminal Justice in Early Oregon, 1842-1859 Author: Ferrell, John Samuel Year: 1973 Indian-white relations in early Oregon are often viewed in terms of warfare and treatymaking, but these are only the most obvious aspects of a larger struggle to resolve cultural conflicts, settle land disputes, and establish order in a new territory. Additional understanding of both white attitudes toward Indians and of Indian exasperation with the settlers may be gained from a study of how criminal justice applied to the red man during the turbulent pre-reservation era. Prior to the coming of America settlers, Oregon Indians knew the justice of the Hudson's Bay Company. In dealing with personas accused of harming HBC personnel or property, Dr. John McLoughlin acted with firmness and persistence while taking cognizance of the Indian's own ideas of just treatment, The American leaders of later years sometimes imitated McLoughlin's firmness but failed to recognize the importance of Indian tradition. Dr. Elijah White, after bring appointed the first U.S. Indian agent for Oregon in 1842, presented the natives with a law code which largely ignored their own traditions and confused them by making major offenses of what had formerly been viewed as minor infractions. Dr. White assured his charges that the new law code came from God and was recognized by all civilized nations. A similar smugness was apparent in later leaders who were convinced that the court proceedings against Indian troublemakers could not help but make a deep and beneficial impression on the defendants' fellow tribesman. Such assurance sometimes blinded the whites to inequities in their application of justice to Indian-white disputes and this blindness contributed to friction between the races. Criminal justice for Indians was a more complex matter during Oregon's territorial period than it had been during the HBC era. To the Indians, the British had been trading partners, but the Americans were dispossessors. A sizable influx of settlers preceded the signing of the Indian treaties, and the presence of two divergent cultures on the same disputed ground made necessary some means of dealing with the disagreements which inevitably arose. But civil officials, army officers, judges, and Indian agents were still working out their respective spheres of influence while new settlers might be many miles away from any hands. The belief expressed by leading figures in the army and the Indian Bureau that whites were to blame for outbreaks of violence did not encourage irate settlers or miners to rely on these agencies to settle disputes with Indians, and citizens' courts, minors' committees, or indiscriminate reprisals were often only forms of "justice" employed. Indians noted the infrequencies of prosecution for whites who committed crimes against them and complained that the whites had one set of laws for themselves and another for the red man, Adverse public opinion worked against the efforts of Indian superintendent Joel Palmer to correct this grievance, and lawyers sometimes questioned whether Indian were, in fact, "persons" or whether their mistreatment could constitute a crime. Even Dick Johnson, a successful Indian farmer who abandoned his native culture and won the support of Palmer and of Jesse Applegate in his efforts to model his life on white men's ideals, had so little legal identity that his suspected murderers were not tried and one of them was allowed to take his farm. Segregation of land and of peoples was the distraction in which both the law and public opinion pointed in Oregon Territory. Consciously and unconsciously, whites encouraged Indians to accept a reservation solution to the problems generated by land-hunger and culture clash, and among these problems legal discrimination and vigilante justice figured prominently. Hatred of the Indians among many of the settlers contributed substantially to distortion and non-application of criminal justice, but even with favorable public opinion, as in the case of Dick Johnson, the law itself was insufficient for an Indian who did not remove himself from white society and accept the treaty protections of the reservation. Close

• 9. [Article] Rural Water

  In Rural Water, Amos Durand struggles to bring in the year's corn crop amid constant rain, marital strife, and his son's peculiar role in a murder investigation.

  Citation × Citation Citation Abstract Copy Title: Rural Water Author: Mollet, Daniel Ray Year: 2013 In Rural Water, Amos Durand struggles to bring in the year's corn crop amid constant rain, marital strife, and his son's peculiar role in a murder investigation. Title: Rural Water Author: Mollet, Daniel Ray Year: 2013 In Rural Water, Amos Durand struggles to bring in the year's corn crop amid constant rain, marital strife, and his son's peculiar role in a murder investigation. Close

• 10. [Article] An Evaluation of the Nontarget Effects of Transgenic Bacillus thuringiensis Maize on Arbuscular Mycorrhizal Fungi in the Soil Ecosystem

  My dissertation research examined the effect of the cultivation of insect-resistant Bacillus thuringiensis (Bt) maize on the soil environment with a goal of understanding how to obtain a balance between ...

  Citation × Citation Citation Abstract Copy Title: An Evaluation of the Nontarget Effects of Transgenic Bacillus thuringiensis Maize on Arbuscular Mycorrhizal Fungi in the Soil Ecosystem Author: Cheeke, Tanya Elizabeth Amy Year: 2013 My dissertation research examined the effect of the cultivation of insect-resistant Bacillus thuringiensis (Bt) maize on the soil environment with a goal of understanding how to obtain a balance between technological advancement and maintenance of a healthy soil ecosystem. Although Bt plants may help to reduce pesticide use, conferring benefits to farm workers and the environment, there are still unresolved questions about how the cultivation of Bt plants affects soil organisms. For this dissertation project, I used 14 different genotypes of Bt maize and non-Bt maize (Zea mays) to investigate the effects of transgenic Bt plants on the colonization ability, abundance, and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) in the soil ecosystem over time. My greenhouse studies demonstrated that Bt maize plants exhibited reduced AMF colonization across multiple Bt genotypes and that effects were most pronounced when fertilizer levels were limited and spore density was high. In addition, I found that although differences in AMF colonization between Bt and non-Bt maize were difficult to detect in the field, spore density was reduced in Bt field plots after just one growing season. When I tested the effect of plot history on AMF and plant growth, I found that Bt and non-Bt maize plants had higher leaf chlorophyll content when grown in plots previously cultivated with the same maize line as the previous year, indicative of a positive feedback effect. I also examined potential mechanisms contributing to the reduced AMF colonization observed in Bt maize in greenhouse studies and determined that follow-up experiments should continue to investigate differences in root apoplastic invertase activity and root permeability in Bt and non-Bt maize. Future investigations would also benefit from examining potential differences in root exudate profiles and volatile organic compounds between Bt and non-Bt cultivars. Taken together, my dissertation results suggest that, while difficult to detect in the field, reductions in AMF colonization in Bt maize roots may be ecologically significant as they could lead to a decrease in the abundance of AMF propagules in the soil over time, potentially impacting soil structure and function in areas where Bt crop cultivation is high. Title: An Evaluation of the Nontarget Effects of Transgenic Bacillus thuringiensis Maize on Arbuscular Mycorrhizal Fungi in the Soil Ecosystem Author: Cheeke, Tanya Elizabeth Amy Year: 2013 My dissertation research examined the effect of the cultivation of insect-resistant Bacillus thuringiensis (Bt) maize on the soil environment with a goal of understanding how to obtain a balance between technological advancement and maintenance of a healthy soil ecosystem. Although Bt plants may help to reduce pesticide use, conferring benefits to farm workers and the environment, there are still unresolved questions about how the cultivation of Bt plants affects soil organisms. For this dissertation project, I used 14 different genotypes of Bt maize and non-Bt maize (Zea mays) to investigate the effects of transgenic Bt plants on the colonization ability, abundance, and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) in the soil ecosystem over time. My greenhouse studies demonstrated that Bt maize plants exhibited reduced AMF colonization across multiple Bt genotypes and that effects were most pronounced when fertilizer levels were limited and spore density was high. In addition, I found that although differences in AMF colonization between Bt and non-Bt maize were difficult to detect in the field, spore density was reduced in Bt field plots after just one growing season. When I tested the effect of plot history on AMF and plant growth, I found that Bt and non-Bt maize plants had higher leaf chlorophyll content when grown in plots previously cultivated with the same maize line as the previous year, indicative of a positive feedback effect. I also examined potential mechanisms contributing to the reduced AMF colonization observed in Bt maize in greenhouse studies and determined that follow-up experiments should continue to investigate differences in root apoplastic invertase activity and root permeability in Bt and non-Bt maize. Future investigations would also benefit from examining potential differences in root exudate profiles and volatile organic compounds between Bt and non-Bt cultivars. Taken together, my dissertation results suggest that, while difficult to detect in the field, reductions in AMF colonization in Bt maize roots may be ecologically significant as they could lead to a decrease in the abundance of AMF propagules in the soil over time, potentially impacting soil structure and function in areas where Bt crop cultivation is high. Close