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361. [Article] The great fires : Indian burning and catastrophic forest fire patterns of the Oregon Coast Range, 1491-1951
The purpose of this study is to examine the relationship between land management practices of Indian communities prior to contact with Europeans and the nature or character of subsequent catastrophic forest fires ...Citation Citation
- Title:
- The great fires : Indian burning and catastrophic forest fire patterns of the Oregon Coast Range, 1491-1951
- Author:
- Zybach, Bob
The purpose of this study is to examine the relationship between land management practices of Indian communities prior to contact with Europeans and the nature or character of subsequent catastrophic forest fires in the Oregon Coast Range. The research focus is spatial and temporal patterns of Indian burning across the landscape from 1491 until 1848, and corresponding patterns of catastrophic fire events from 1849 until 1951. Archival and anthropological research methods were used to obtain early surveys, maps, drawings, photographs, interviews, Geographic Information Systems (GIS) inventories, eyewitness accounts and other sources of evidence that document fire history. Data were tabulated, mapped, and digitized as new GIS layers for purposes of comparative analysis. An abundance of historical evidence was found to exist that is useful for reconstructing precontact vegetation patterns and human burning practices in western Oregon. The data also proved useful for documenting local and regional forest fire histories. Precontact Indians used fire to produce landscape patterns of trails, patches, fields, woodlands, forests and grasslands that varied from time to time and place to place, partly due to demographic, cultural, topographic, and climatic differences that existed throughout the Coast Range. Native plants were systematically managed by local Indian families in even-aged stands, usually dominated by a single species, throughout all river basins of the study area. Oak, filberts, camas, wapato, tarweed, yampah, strawberries, huckleberries, brackenfern, nettles, and other plants were raised in select areas by all known tribes, over long periods of time. However, current scientific and policy assumptions regarding the abundance and extent of precontact western Oregon old-growth forests may be in error. This study demonstrates a high rate of coincidence between the land management practices of precontact Indian communities, and the causes, timing, boundaries, severity, and extent of subsequent catastrophic forest fires in the same areas. Information provided by this study should be of value to researchers, wildlife managers, forest landowners, and others with an interest in the history and resources of the Oregon Coast Range.
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362. [Article] Curriculum synthesis and amelioration : a case study of undergraduate civil engineering
The dynamic philosophy of education as applied to the undergraduate Civil Engineering program has been influenced by such factors as the introduction of new theories, the demands and needs of our society ...Citation Citation
- Title:
- Curriculum synthesis and amelioration : a case study of undergraduate civil engineering
- Author:
- Hamernik, Robert E.
The dynamic philosophy of education as applied to the undergraduate Civil Engineering program has been influenced by such factors as the introduction of new theories, the demands and needs of our society and the personnel responsible for teaching. These changes are reflected in the curriculum as witnessed by a historical development leading to the philosophy of the past two decades during which time significant emphasis has been placed on an increased scientific base in undergraduate education. To evaluate this shift and its effect on the educational product, a total of 464 questionnaires were mailed to various private and governmental agencies, and the industry representative was asked to randomly select a respondent with the only limitation being a Civil Engineering graduate of preferably five years or less. A response of 78.7 percent of all the questionnaires mailed was received with the graduates identifying their major work responsibility as either design oriented, management, construction or research. The survey form contained a series of questions developed from two given statements relative to the current philosophy upon which the curriculum is based and also the role of the professor with emphasis on research and teacher preparation. To analyze the input data, a t-Test statistic was derived so that each responsibility composite profile could be tested against the total response. A similar analysis was made for the graduates based on government or private industry employment. In addition, the questionnaire was designed to provide data so that an undergraduate curriculum could be constructed from a mathematical model using the number of semester units per academic subject area as the parameters. A computer program was written to evaluate the subject unit distribution matrix, assuming a curriculum which consisted of 130 units, for the total response and for each of the four work responsibility divisions. These values were compared to a typical curriculum computed from the programs offered by fifty ECPD accredited universities and colleges across the United States. The findings of this study showed that a majority, 81.9 percent of the total response, favored redirecting the primary educational goal of the undergraduate Civil Engineering program to insure adequate exposure to the art of engineering. Likewise, the graduates expressed concern over the lack of student involvement in the engineering program during the first two years of study, improving the quality of teaching and felt a need for additional student-faculty exchange and contact outside the formal classroom activities. Relative to the role of research and its implications to effective teachings the response indicated that practical experience would be more relevant to teaching. In addition the data further revealed that academic advancement should not be so closely dependent upon the research efforts of the professor. The curriculum developed yielded a redistribution of 14 units, equivalent to 10.8 percent of the total units, with the largest increase devoted to additional study in the area of engineering analysis and design.
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363. [Article] Natural history and evolution of a color polymorphism in Rana pipiens, the northern leopard frog
A primary goal of population genetics is to identify the role of microevolutionary forces in producing observed patterns of molecular and phenotypic variation. I conducted four studies in the northern ...Citation Citation
- Title:
- Natural history and evolution of a color polymorphism in Rana pipiens, the northern leopard frog
- Author:
- Hoffman, Eric Adam
A primary goal of population genetics is to identify the role of microevolutionary forces in producing observed patterns of molecular and phenotypic variation. I conducted four studies in the northern leopard frog, Rana pipiens, to determine just how mutation, migration, genetic drift, and selection influenced, genetic structure of mitochondrial DNA (mtDNA), nuclear DNA, and a single locus polymorphism that determines dorsal coloration. In the first study, I surveyed the literature concerning color and pattern polymorphisms in anurans. I conclude that anuran polymorphisms remain a rich but largely unexploited system for studying the evolution of phenotypic variation in nature. In the second study, I compared mitochondrial DNA variation from 35 populations distributed across the species' range. A phylogenetic analysis indicated R. pipiens is split into two deeply divergent mtDNA groups, a western group and an eastern group. Phylogeographic and demographic analyses indicated that although restricted gene flow with isolation by distance explained the majority of the processes influencing current genetic structure, population bottlenecks and expansions also played an important role. In the third study, I investigated mtDNA and microsatellite variation in Pacific Northwest populations of R. pipiens, where a recent range contraction had occurred. I found that peripheral populations had reduced levels of genetic variation compared to more interior populations. Moreover, I found that historic samples from peripheral population already had reduced levels of genetic variation. Therefore, low diversity in the remnant populations could not be ascribed to the recent range contraction. In the fourth study, I compared genetic structure from a suite of putatively neutral molecular markers with that derived from the color polymorphism locus. Genetic structure at the color locus, assessed both spatially and temporally, was indistinguishable from structure at neutral loci. This study exemplifies the importance of investigating for evidence of selective maintenance before studies attempt to measure the selective mechanisms maintaining a polymorphism. Overall, my research helps to elucidate how biogeographic and microevolutionary forces influence a wide-spread North American species, R. pipiens.
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364. [Article] Industrial engineering in America as a guide for industrial engineering education in Kore
The purpose of this study is to investigate the direction of future Korean industrial engineering education and to suggest how U.S. experiences can guide Korean developments. The leading indicator concept, ...Citation Citation
- Title:
- Industrial engineering in America as a guide for industrial engineering education in Kore
- Author:
- Ro, In Kyu
The purpose of this study is to investigate the direction of future Korean industrial engineering education and to suggest how U.S. experiences can guide Korean developments. The leading indicator concept, correlation coefficients are utilized. The following statistical relationships were developed and the following educational and practical industrial engineering trends in the U.S. are surveyed through literature: 1. Statistical relationships between Korean economy and industry during the 1961 - 1970 period and the U.S. experience during the 1948 - 1957 period. 2. Statistical relationships of IE enrollment to seven manufacturing industries in the U.S. during the 1948 - 195 7 period. 3. The trends of industrial engineering curricula in the U. S. from 1958-1959 to 1971-1972. 4. The trends of industrial engineering education and the practices in the U.S. during the 1962 - 1966 period. It is concluded that the U.S. during the 1948 - 19 57 period is a "leading indicator" for economic and industrial developments in Korea during the 1961 - 1970 period. Therefore, unless Korean developments depart radically from historical patterns, the 1962 - 1965 conditions for industrial engineering in the U. S. should suggest what logically to expect in Korea during the 1975 - 1978 period. Based on these conditions, the following suggestions should guide current industrial engineering developments in Korea: 1. Initial efforts should emphasize traditional industrial engineering subjects that are immediately applicable in Korean economy. 2. The curriculum design should make use of the experience of U. S. developments in industrial engineering education which suggest an integration of basic science with engineering subjects and inclusion of humanities and social sciences. 3. After a basic IE program has been established in Korea, more sophisticated mathematical and statistical tools can be added. Revisions must be made to keep the curriculum current. Graduate studies in industrial engineering should not be initiated until production processes in Korean industries become more complex and can benefit from advanced IE techniques. 4. A faculty development program should be implemented. 5. Plans should be developed to show industry what IE's can do and to get support of government and industry for Cooperative programs. 6. Cooperative programs should be started. 7. Staff and educational resources should be improved. 8. Develop IE technicians. 9. Methods for serving small and medium industries should be developed. Many of the obstacles facing the introduction of industrial engineering to Korea can be overcome by actions such as affiliating Korean and U. S. universities, exchanging study teams and consultants, advertising by publications and conferences what can be gained by using IE tools, acquiring IE reference materials and sponsoring IE consultations for small Korean industries.
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Upper Klamath Lake in southern Oregon has two species of lacustrine suckers, Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris that were historically abundant. Results of ...
Citation Citation
- Title:
- Age and growth of young-of-the-year Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris of Upper Klamath Lake, Oregon
- Author:
- Logan, Daniel Joseph
Upper Klamath Lake in southern Oregon has two species of lacustrine suckers, Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris that were historically abundant. Results of surveys performed in the mid-1980's indicated that populations of both species were declining and ageing with apparent recruitment failure in most years since 1970. In 1988 both species were listed as endangered species and high priority has been placed on investigating recruitment of Upper Klamath Lake suckers. Lapilli are the preferred otolith for ageing suckers. Lapilli form predictably on the day of hatch, have the most conservative morphology of the three otoliths, and deposit easily discernable increments that begin on the day of hatch and proceed daily, and grow in a predictable relationship with somatic growth. Ages estimated by otolith analysis and resulting hatch dates of young-of-the-year Lost River sucker and shortnose sucker were consistent annually and consistent with reported spawning period for suckers from Upper Klamath Lake. Otolith increment analysis is necessarily lethal, whereas scale circuli analysis is not lethal. My findings suggest that scale circuli count is an inefficient estimator of daily Daily age estimates for age in young-of-the-year Lost River sucker and shortnose sucker. any given circuli count varied by approximately 51 days in Lost River sucker and 30 days Additionally, my results do not accurately predict the size or age at in shortnose sucker. which scales are formed, thereby invalidating an assumption of age and growth models. Consequently, scale circuli analysis cannot be used to produce accurate estimates of age or growth for young-of-the-year Lost River sucker and shortnose sucker. Lost River sucker and shortnose sucker achieve a relatively large size by the autumn of their first year, consistent with other members of Catostomidae. Interspecific difference in growth rates was evident in each year with Lost River sucker exhibiting faster growth than shortnose sucker in each year. Abundance of young-of-the-year suckers does not appear to be strongly correlated to somatic growth rate, though hatch date and environmental parameters are highly correlated with abundance. In both Lost River sucker and shortnose sucker, in years with the highest abundance (1991 and 1993), the mean hatch dates of surviving fish were later than in years with the lowest abundance. Also, young-of-the-year Lost River sucker and shortnose sucker experienced wide environmental fluctuations in Upper Klamath Lake as seasonal limnological and climatic variation create a dynamic habitat for young suckers. Water temperature, precipitation, air temperature, and minimum lake elevation are all strongly correlated to abundance of young-of-the-year suckers.
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366. [Article] Intraethnic diversity : an exploratory study of ethnic identity of Chinese American adolescents
The purpose of the study was to explore the ethnic identity of Chinese American adolescents through the investigation of relationships between ethnic identity and selected demographic, sociocultural, and ...Citation Citation
- Title:
- Intraethnic diversity : an exploratory study of ethnic identity of Chinese American adolescents
- Author:
- Lee, Phyllis S.
The purpose of the study was to explore the ethnic identity of Chinese American adolescents through the investigation of relationships between ethnic identity and selected demographic, sociocultural, and psychological characteristics. Data were obtained from 106 Chinese American youth between the ages of 14 and 21 through the use of two instruments designed for the study. Three dimensions of ethnic identity were measured by subscales of the Sinoethnic Identity Scale. Demographic, sociocultural, and psychological data were obtained from the Background Information Survey. The strongest ethnic identities were found in the traditional, or core, dimension which was comprised of fundamental values, customs, and traditions. Weaker ethnic identities were exhibited in the intermediate, or familial, dimension which was responsible for the transmission of the ethnic culture as well as the preparations for interfacing the larger society. It was suspected that this dimension held the greatest potential for intercultural and intragenerational conflicts for Chinese American adolescents. The neutral stance taken in the societal dimension suggested two divergent interpretations: students may be exhibiting ambivalent feelings toward their ethnic identities within the scheme of life, or students may have come to terms with the notion of bicultural identities. Step-wise multiple regression was used to analyze the data. School achievement emerged as the most significant variable in the traditional dimension, suggesting that a Chinese heritage may not ensure school success, but school success contributed to the definition of being Chinese. In the familial dimension it was found that the gender of the subject was the most important variable. Subjects appeared to be highly socialized into ethnically appropriate sex roles, although there were indications of disagreement with the actual practice of these roles. Church attendance was identified as the most significant variable of the societal dimension. Those who attended church exhibited stronger agreement with ethnically appropriate social behaviors and expressed preferences for social activities and relationships within the ethnic community. The findings indicated that ethnic identity was a multidimensional aspect in the lives of Chinese American youth. The three dimensions that comprised Chinese ethnic identity appeared to be differentially affected by demographic, sociocultural, and psychological phenomena. It was also speculated that there was a relationship between the acknowledgement and expression of ethnic identity and historical and contemporary social , economic, and political conditions of society. The range of intraethnic diversity expressed by Chinese American adolescents suggested the need for reexamination of assumptions and expectations currently held by educational personnel. Recommendations for future research which might lead to the provision of educational policies and practices appropriate to Chinese American youth, a more informed understanding of the Chinese experience in the United States, and a greater understanding of the impact of ethnic identity in the lives of minority youth were presented.
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367. [Article] Why aren't pigeon guillemots in Prince William Sound, Alaska recovering from the Exxon Valdez oil spill?
The Pigeon Guillemot (Cepphus columba) is now the only species of marine bird in Prince William Sound (PWS), Alaska that is listed as "not recovering" on the Exxon Valdez Oil Spill (EVOS) Trustee Council's ...Citation Citation
- Title:
- Why aren't pigeon guillemots in Prince William Sound, Alaska recovering from the Exxon Valdez oil spill?
- Author:
- Bixler, Kirsten S.
The Pigeon Guillemot (Cepphus columba) is now the only species of marine bird in Prince William Sound (PWS), Alaska that is listed as "not recovering" on the Exxon Valdez Oil Spill (EVOS) Trustee Council's Injured Resources List and has shown no sign of population recovery. During the 20 years since EVOS, the guillemot population in PWS has gradually declined by nearly 50% following the initial mortality event caused by direct contact with spilled oil. This decline has continued even though there is no longer evidence that guillemots are negatively affected by residual oil from EVOS. My objectives in this study were to (1) identify the primary factor now limiting Pigeon Guillemot population recovery at the Naked Island group, the most important historical breeding area for guillemots in PWS, and (2) determine whether guillemot population trends across PWS are consistent with my understanding of the primary limiting factor. I investigated two competing hypotheses for the lack of guillemot recovery at the Naked Island group: availability of high quality prey (i.e., schooling forage fish) and nest predation. The prevalence of schooling forage fish in the diet of Pigeon Guillemots at the Naked Island group has not recovered to pre- EVOS levels. However, data from both aerial surveys and beach seines provided evidence of an increase in abundance of schooling forage fish near the Naked Island group since the late 1990s. Yet between 1990 and 2008, there was a precipitous 12% per annum decline in the guillemot population at the Naked Island group, where mink are present, while at the nearby mink-free Smith Island group guillemot numbers were stable. The mortality rate of guillemot eggs and chicks at the Naked Island group was high during the late 1990s, largely attributable to predation by mink. The weight of evidence indicates that predation by mink is now the primary factor limiting the reproductive success and population recovery of Pigeon Guillemots at the Naked Island group. Differences in guillemot population trends between the Naked Island group and the remainder of PWS are also consistent with the mink predation hypothesis. The median decline in density of Pigeon Guillemots along transects at the Naked Island group was much greater (> 7 times) than the decline along transects throughout the remainder of PWS. The proportion of all guillemots in isolated pairs (as opposed to multi-pair groups) increased substantially only at the Naked Island group. This is consistent with the hypothesis that mink predation negatively affected guillemot colonies more than isolated nesting pairs; perhaps because guillemot nests in colonies were more apparent or more accessible to mink. At other high-density guillemot nesting areas in PWS, average group size of guillemots declined from 12 to 8 individuals suggesting that other factors may play a role in constraining of guillemots on a region-wide scale, perhaps availability of schooling forage fishes. Nevertheless, I conclude that the key to restoring the injured guillemot population at the Naked Island group is to eliminate mink predation pressure on guillemot eggs, nestlings, and attending adults.
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368. [Article] Community-based sea turtle conservation in Baja, Mexico : integrating science and culture
This thesis discusses both theoretical and practical considerations inherent in conducting community-based research within a case study of sea turtle conservation in Baja California, Mexico. A brief background, ...Citation Citation
- Title:
- Community-based sea turtle conservation in Baja, Mexico : integrating science and culture
- Author:
- Bird, Kristin E.
This thesis discusses both theoretical and practical considerations inherent in conducting community-based research within a case study of sea turtle conservation in Baja California, Mexico. A brief background, including the general ecology, status and distribution of sea turtles of the Baja peninsula is presented, with an overview of the current and historic use and management of sea turtles. Several sets of theories provide the context within which the case example is analyzed. A discussion of how concepts of "science" and "knowledge" are shaped and how these perceptions impact choices made in natural resource management and planning is presented. This includes a brief discussion of conservation ethics and conservation rationale, as well as a review of the debates surrounding indigenous knowledge and its application in conservation. A review of community-based efforts in sea turtle conservation is also presented. The data and analysis offered in this thesis is the result of two field seasons working as a member of an interdisciplinary sea turtle conservation team: conducting biological studies, surveys, informal and semi-structured interviews and participant observation. The major goal of this research project was to evaluate a people-oriented approach to conservation. The objectives of the Baja sea turtle conservation project included: the involvement of fishing communities in the development of conservation projects, the involvement of local students and fishermen in the collection of data and the public sharing of research results on a regular basis. Results of this case study suggest that through dependence on the host community for food, equipment, labor and guidance a special connection was established, fostering trust and building the partnerships necessary for long-term conservation success. For this reason, fishermen and other members of the local host communities were more willing to cooperate with outsiders and share their intimate knowledge of their environment - including information on the daily movements and distribution of sea turtles. It is crucial that the fishermen feel empowered before they choose to participate in the sea turtle conservation efforts. They must be viewed, and view themselves, as an integral part of the conservation team contributing valuable knowledge and ideas, not just acting as boat drivers and guides for outside researchers within the host community. Community meetings served as an outlet to voice concerns and share information. The active involvement and participation of local communities is a highly effective tool in the sea turtle conservation efforts in the region.
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Access to health care in North Dakota, a frontier state, has been a widely debated policy issue. Historically, the focus of North Dakota health policy efforts has been directed to issues pertaining to ...
Citation Citation
- Title:
- A study of health insurance coverage and health care utilization in North Dakota
- Author:
- Knudson-Buresh, Alana
Access to health care in North Dakota, a frontier state, has been a widely debated policy issue. Historically, the focus of North Dakota health policy efforts has been directed to issues pertaining to the provision of health care services. During the economic recession of the I 980s, an out-migration of North Dakota residents left the state with a smaller population in 1990 than it had in 1930, the only state to experience this population shift. In response to these demographic shifts, the North Dakota Health Task Force was formed to develop a health care reform strategy that addressed geographical and financial health care access issues. Over 2,000 North Dakota families were surveyed to provide the Task Force and other policy makers with information about North Dakota residents' health insurance coverage and health care utilization. The purpose of this research was to examine what variables impact access to health insurance coverage and utilization of health care services in North Dakota. Three access areas were addressed: financial, geographical and cultural. To examine financial access, health insurance coverage was examined. Among the non-institutionalized ND residents, the greatest proportion of uninsured were young adults; although, all North Dakotans were found to be at risk. The health insurance findings mirrored many other studies' findings in which males, part-time workers and rural dwellers were the most likely to go without insurance. In addition, health insurance appears to serve as a gatekeeper for obtaining health care services. A surprising finding was that geographic barriers were not a hindrance to obtaining health care. Yet, Native Americans covered by Indian Health Service were less likely to obtain health care than the uninsured indicating there may be some cultural barriers for this population. Other findings included: the uninsured go without health care and report lower health status more frequently than the insured; poverty level is positively correlated with health status; among those with no regular source of health care, the insured report they do not need health care while the uninsured report they cannot afford it. Comparisons of rural and urban dwellers also are included in the analyses.
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370. [Article] A methodology for analysis of historic textiles Ancon, Peru
Twenty-four woven Pre-Columbian textiles in the Apparel, Interiors and Merchandising Department (AIM) of Oregon State University were reported to be from Ancon, Peru. A methodology was developed to confirm ...Citation Citation
- Title:
- A methodology for analysis of historic textiles Ancon, Peru
- Author:
- Ishikawa, Sally Jo
Twenty-four woven Pre-Columbian textiles in the Apparel, Interiors and Merchandising Department (AIM) of Oregon State University were reported to be from Ancon, Peru. A methodology was developed to confirm the exact provenance of the AIM textiles. Technical fabrication characteristics were utilized to describe certain known Ancon woven textiles and to analyze the twenty-four AIM textiles; then comparisons were attempted between the two groups to determine if internal patterns for each were identical. A literature and collection survey identified ten documented reports of known Ancon woven textiles. The previously recorded information of the known Ancon pieces was summarized. Technical fabrication characteristics for each AIM textile were observed and recorded. The technical fabrication characteristics included weave structure, thread count, fiber content, direction of spin, ply, degree of twist, yarn diameter, color and motif. Frequencies and especially developed analysis tools were utilized to identify internal patterns. Hypothesis 1 stated that information about the technical fabrication elements of Ancon woven textiles in certain other collections can be organized into integrated patterns. Hypothesis 1 was not supported because data recorded on Ancon woven textiles was incomplete, and therefore only able to give limited frequencies. Hypothesis 2 was supported: The twenty-four woven Pre-Columbian textiles from the Costume and Textile Collection of the Apparel, Interiors and Merchandising Department of Oregon State University will have similar patterns in technical fabrication elements. An analysis tool was developed to show patterns within technical fabrication elements. Thread count, direction of spin, ply, and degree of twist exhibited internal patterns. Hypothesis 3 stated that the provenance of twenty-four woven Pre-Columbian textiles, from the Costume and Textile Collection of the Apparel, Interiors and Merchandising Department of Oregon State University is Ancon, Peru. This hypothesis could not be tested because technical fabrication patterns for the known Ancon weavings were not complete and could not be statistically analyzed. Even though the two sets of data populations (data from known Ancon textiles and data from the AIM collection) could not be compared statistically, some information was gained by a review and comparison of simple frequencies of internal patterns. Thread count frequencies for both populations exhibited internal patterns.
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In 1986, researchers from Oregon State University, led by Dr. David Brauner, came to the small Catholic community of St. Paul, Oregon as part of ongoing research on the French-Canadian inhabitants of the ...
Citation Citation
- Title:
- Women of valor : the Sisters of Notre Dame de Namur, St. Paul, Oregon, 1844-1852
- Author:
- Poet, Rebecca McClelland
In 1986, researchers from Oregon State University, led by Dr. David Brauner, came to the small Catholic community of St. Paul, Oregon as part of ongoing research on the French-Canadian inhabitants of the Willamette Valley between 1829 and the mid-1860s. They were searching for the remains of the first Catholic Mission in the Pacific Northwest. What they found was a cellar belonging to nuns who ran a boarding school for the daughters of the French-Canadians between 1844 and 1852. These women were upper-middle class Belgians belonging to the Sisters of Notre Dame de Namur order. The purpose of this research was to examine the archaeological data recovered from this project to see whether this novel situation was recognizable in the archaeological record. Secondly the objective was to intensively review the written record to determine details regarding the daily lives of these women. The final objective was to see what the combination of literature and archaeology can reveal about the texture of their lives. The research was divided into three phases: field archaeology, literature search, and artifact analysis. Field archaeology was accomplished over two field seasons and included pedestrian survey and surface collection and test pit and block excavation. Artifact analysis was loosely structured on a functional classification developed by Roderick Sprague. Artifacts were broken into three study units: block excavation, surface collection, and test pit excavation. Six Sisters of Notre Dame de Namur set foot on the shores of the Oregon Territory on August 1, 1844. They were the first Catholic nuns to come to the Pacific Northwest. Coming at the invitation of Father Francis Norbert Blanchet, they set up a boarding school for the daughters of the retired French-Canadian fur trappers who had settled in the Willamette Valley. Their school was in the small Catholic community of St. Paul. During their short stay in St. Paul they taught school while learning to survive. They developed skills such as bread-making, clothes washing, carpentry, livestock husbandry, and gardening. They left the Willamette Valley in 1852 and moved to San Jose in California where they established a college. The written record shows that the site where the Sisters lived served a dual function as a religious and educational facility and as a homestead. Archaeological evidence exists for the educational facility and homestead, but the religious aspect of the site was not apparent. The historical record shows that the inhabitants of the site were unique individuals within the location of French Prairie. The archaeology supports this, but does not definitively indicate gender, class, or ethnicity.
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372. [Article] The effect of precipitation variation on soil moisture, soil nitrogen, nitrogen response and winter wheat yields in eastern Oregon
The semi-arid regions of the Pacific Northwest are characterized by a high degree of annual temperature and precipitation variation. As a result of this climatic variation, dryland nitrogen fertilizer ...Citation Citation
- Title:
- The effect of precipitation variation on soil moisture, soil nitrogen, nitrogen response and winter wheat yields in eastern Oregon
- Author:
- Glenn, D. M. (David Michael)
The semi-arid regions of the Pacific Northwest are characterized by a high degree of annual temperature and precipitation variation. As a result of this climatic variation, dryland nitrogen fertilizer trials on fallow- ,wheat rotations typically demonstrate a variable response. Wheat growers in the area must not only cope with this climatic variation and its sundry effects upon their livelihood, they must also make decisions regarding the future level of anticipated climatic variation. The specific objectives were to: 1) develop a climatically responsive yield potential prediction model for soft white winter wheat from historical data at the Sherman Branch Experiment Station (Moro, OR); 2) modify this model for use on commercial fields; 3) field simulate five fallow-crop precipitation patterns characteristic of the variation found in the Sherman county area of eastern Oregon in order to test the yield potential model: 4) examine the effects of precipitation variation on nitrogen fertilizer responses, moisture storage and depletion and nitrogen mineralization; and 5) establish a quantitative relationship between precipitation/ soil moisture and nitrate accumulation in both the fallow and crop seasons. Two interacting regression models were developed to estimate grain yield levels in the 250-350 mm precipitation zone of eastern Oregon. The first model estimates yield potential from monthly precipitation and temperature values. The second model estimates the percent grain reduction due to delayed crop emergence. The grain yield model was adapted to commercial fields using a Productivity Index factor (PI). The PI is a measure of the productivity of other locations in relation to the Sherman Branch Experiment Station, using water-use-efficiency (WUE) as the basis of comparison. The field simulation of five fallow-crop precipitation patterns demonstrated that the maximum grain yield response occurred at 40 kg N (soil + fertilizer)/metric ton. The grain yield model demonstrated a 15% level of accuracy on a commercial field basis in both field trials and a survey of past production levels (1972-1980). It was hypothesized that the distribution of precipitation in the fallow and crop periods had an effect on both the amount and distribution of stored soil moisture. The field simulation demonstrated that more soil moisture was stored at the 90-240 cm depths by the patterns with more fallow season precipitation when measured in March of the crop year. Soil moisture storage and storage efficiencies fluctuated throughout the fallow and crop periods. At the cessation of the winter precipitation season in both the fallow and crop periods (March), the storage efficiency was highest when low levels of precipitation occurred. At this point in time, the mean crop period storage efficiency was 10% below the mean fallow period storage efficiency (34 and 44%, respectively) in both simulation studies. Soil moisture, temperature and immobilization requirements of crop residues interact to affect the net amount of nitrogen mineralization. The mineralization model proposed by Stanford and Smith (1972) was tested under field conditions. When the nitrogen immobilization requirement of the crop residues was included, the actual and predicted values were in agreement at the close of the 1978 fallow period. A nitrogen deficit was predicted at the 0-30 cm depth at the close of the 1980 fallow; however, the actual levels indicated a net accumulation of nitrate-nitrogen. Crop season mineralization, inferred from Mitscherlick and a-value extrapolations, in 1979 demonstrated that there was a decreasing amount of net mineralization during the crop season with increasing amounts of both fallow and crop season precipitation. Crop season mineralization in 1980 indicated that there was no net accumulation of nitrogen, rather a tie-up of 14 kg N/ha. This result reflects both the unsatisfied immobilization requirement predicted for the 1979 fallow season and crop season denitrification.
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The study of the vegetation of one of the natural coastal prairies in Oregon was undertaken for the purpose of describing some of its synecological features. Specific objectives of the study were to describe ...
Citation Citation
- Title:
- Synecological features of a natural headland prairie on the Oregon coast
- Author:
- Davidson, Eric Duncan
The study of the vegetation of one of the natural coastal prairies in Oregon was undertaken for the purpose of describing some of its synecological features. Specific objectives of the study were to describe certain plant assemblages in the study area, present phenological relationships on some of the assemblages, and discuss and illustrate some examples of evidence of succession on the study area. The study area is a prairie located on a headland about one mile north of the Tillamook-Lincoln county line (Sec. 3 in T6S, R11W). This prairie is one of the many situated on the headland bluffs and slopes along the northern Pacific coast. During an initial period of reconnaissance, familiarization with the plant species and communities in the study area was gained. Several surveys along most of the Oregon coast were made to compare the study area with other coastal prairies. A total of 38 distinctive stands of vegetation within the prairie were sampled in a series of five repetitive sessions from January to October in 1966. Presence and vegetative cover of species were recorded. In addition, soil depths in these stands were recorded. Seven transects from the prairie through the ecotone to the forest were established and the presence of species along them was recorded. With the aid of an association table five distinctive communities were differentiated in the sampled stands. These were: 1. Equisetum maximum community, restricted to sites with high soil moisture during the entire year. 2. Polystichum munitum-Rubus parviflorus community, usually on soils 18 inches deep or less. Species in this community form the major part of the ecotone vegetation. 3. Carex obnupta community, usually on soils 12 inches deep or less. Carex is the only important species in this community. 4. Artemisia suksdorfii-Solidago canadensis community, found on the exposed, south-facing end of the prairie on deep soils. It is a community found commonly in prairies farther north on the coast. 5. Solidago canadensis community, situated farther up in the prairie than the Artemisia-Solidago community, on deep soils. It was judged to be an earlier successional stage of the Artemisia-Solidago community. Two more groups were apparent in the table, but these were judged not to be distinct communities in the field. These were: 6. Lupinus littoralis group, considered part of the internal pattern of one or more of the large grassy communities not sampled. The peculiar grouping of Lupinus littoralis is attributed to the large, heavy seeds of that species which always drop directly to the ground, rather than being distributed farther by the wind. 7. Angelica lucida-Rubus spectabilis group, judged to be an aberrant form of the Polystichum-Rubus parviflorus community. A discussion of successional aspects of this and other coastal prairies on the Pacific coast was based on the results of field work carried out during this study, a knowledge of activities on this prairie from 1916 to the present time, and on historical accounts and old photographs concerning the coastal vegetation. It was tentatively concluded that the coastal prairies were maintained for long periods in the past mostly by fires set by the coastal Indians who lived on them. When the white settlers arrived with their cattle and sheep, many prairies, including the study area, were maintained by grazing pressure, and the spread of hardy introduced grasses was encouraged. The stands sampled in the study area were thought to have become established during a period of no stock grazing from 1938 to the present time. It was suggested that the Polystichum munitum-Rubus parviflorus community may provide sites for the growth of Picea sitchensis within this prairie.
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The characterization of bathymetry and its time evolution is very important for both oceanographic science applications, and for societal reasons relating to coastal engineering and development. Historically, ...
Citation Citation
- Title:
- Hybrid approach to estimating nearshore bathymetry using remote sensing
- Author:
- Catalán Mondaca, Patricio A.
The characterization of bathymetry and its time evolution is very important for both oceanographic science applications, and for societal reasons relating to coastal engineering and development. Historically, the process of depth surveying has been costly and labor-intensive. This is especially true in nearshore regions, hence a method that is both economic and reliable is of great interest. In this regard, depth inversion techniques take advantage of the interaction between the surface wave field and the underlying bathymetry such that observations of surface wave propagation can be coupled with a dispersion relation to infer bathymetry. Using field measurements, several different types of wave observation data have been tested in inversion methods, e.g. arrays of pressure sensors (Holland, 2001), marine radar (Bell, 1999), aerial photogrammetry (Dugan et al., 2001) and video imagery (Stockdon and Holman, 2000). Typically, these studies use the linear wave dispersion relation and measured wave phase speeds (c) to perform the inversion, and agreement is generally good in intermediate water depths in the absence of currents; errors increase as waves enter shallow water, increase in nonlinearity, and eventually break. In addition, numerical techniques exist that account for some nonlinear processes (e.g. Kennedy et al., 2000b; Misra et al., 2003) but they require more input data, usually in the form of high resolution free surface measurements. These nonlinear methods can potentially make improved depth estimates, however, they have only been tested with synthetic data. In this study, we undertake a novel approach for investigating phase speeds of nonlinear waves and the potential for using them for depth inversions. The approach is novel in the sense that our observational data set consists of both in situ and remotely sensed data and also high resolution numerical data for interpolating between the in situ measurements. Our observations were made from a set of laboratory experiments conducted in large scale wave flume. Laboratory wave conditions included both regular and random waves and a range of wave heights and periods were considered. The final data set used for the depth inversion algorithm was reduced to regular cases only. The wave height profile H(x) is simulated with high spatial resolution using a combined refraction/difraction model REF/DIF1 (Kirby and Dairymple, 1994), where the in situ data is used for calibration. Next, wave parameters such as phase speed, wavenumber and frequency are estimated based on the remote video measurements. The resulting hybrid data set is used as input for performing depth inversion including nonlinearity using the composite dispersion relation of Kirby and Dalrymple (1986). Results indicate that inclusion of nonlinearity significantly improves the retrieved depths, especially in shallow water. The resulting degree of accuracy is comparable with previous observations for intermediate water. Analysis of the error suggests that the main source of error can be attributed to the phase speed estimation, thus it is apparent that the composite dispersion equation is capable of explaining the principal physical process well.
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375. [Article] Tidal and atmospheric forcing of the upper ocean in the Gulf of California, Part 2: Surface heat flux
Satellite infrared imagery and coastal meteorological data for March 1984 through February 1985 are used to estimate the net annual surface heat flux for the northern Gulf of California. The average annual ...Citation Citation
- Title:
- Tidal and atmospheric forcing of the upper ocean in the Gulf of California, Part 2: Surface heat flux
- Author:
- Abbott, Mark R., Winant, Clinton D., Paden, Cynthia A.
Satellite infrared imagery and coastal meteorological data for March 1984 through February 1985 are used to estimate the net annual surface heat flux for the northern Gulf of California. The average annual surface heat flux for the area north of Guaymas and Santa Rosalia is estimated to be +74 W m-2 for the 1984–1985 time period. This is comparable to the +20–50 W m-2 previously obtained from heat and freshwater transport estimates made with hydrographic surveys from different years and months. The spatial distribution of the net surface heat flux shows a net gain of heat over the whole northern gulf. Except for a local maximum near San Esteban Island, the largest heat gain (+110–120 W m-2) occurs in the Ballenas and Salsipuedes channels, where strong tidal mixing produces anomalously cold sea surface temperatures (SSTs) over much of the year. The lowest heat gain occurs in the Guaymas Basin (+40–50 W m-2), where SSTs are consistently warmer. In the relatively shallow northern basin the net surface heat flux is fairly uniform, with a net annual gain of approximately +70 W m-2. A local minimum in heat gain (approximately +60 W m-2) is observed over the shelf in the northwest, where spring and summer surface temperatures are particularly high. A similar minimum in heat gain over the shelf was observed in a separate study in which historical SSTs and 7 years (1979–1986) of meteorological data from Puerto Penasco were used to estimate the net surface heat flux for the northern basin. In that study, however, the heat fluxes were higher, with a gain of +100 W m-2 over the shelf and +114 W m-2 in the northern basin. These larger values are directly attributable to the higher humidities in the 1979–1986 study compared to the 1984-1985 satellite study. Significant interannual variations in humidity appear to occur in the northern gulf, with relatively high humidities during El Niño years and low humidities during anti-El Niño years. High humidities reduce evaporation and the associated latent heat loss, promoting a net annual heat gain. In the northern Gulf of California, however, tidal mixing appears to play a key role in the observed gain of heat. Deep mixing in the island region produces a persistent pool of cold water which is mixed horizontally by the large-scale circulation, lowering surface temperatures over most of the northern gulf. These cold SSTs decrease evaporation by reducing the saturation vapor pressure of the overlying air. As a result, heat loss is substantially reduced, even when humidities are low. By removing heat from the surface, tidal mixing alters the time scale of air-sea interaction and reduces or possibly even inhibits the formation of deep water masses via convection. Over climatological timescales, it may be tidal mixing that ultimately maintains the estuarinelike circulation in the northern Gulf of California, differentiating it from the Mediterranean and Red seas, which lose heat to the atmosphere.
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377. [Article] Dynamics of Vector-Host Interactions in Avian Communities in Four Eastern Equine Encephalitis Virus Foci in the Northeastern US
This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by the Public Library of Science. The published article can be found at: http://journals.plos.org/...Citation Citation
- Title:
- Dynamics of Vector-Host Interactions in Avian Communities in Four Eastern Equine Encephalitis Virus Foci in the Northeastern US
- Author:
- Molaei, Goudarz, Andreadis, Theodore G., Armstrong, Philip M., Muller, Tim, Thomas, Michael C., Shepard, John J., Medlock, Jan
This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by the Public Library of Science. The published article can be found at: http://journals.plos.org/plosntds/
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378. [Article] Canyon Grasslands of the Hells Canyon National Recreation Area : How have they changed over time and what is their future trajectory?
The canyon grasslands of the Hells Canyon National Recreation Area (HCNRA) are a unique ecosystem within the Pacific Northwest Bunchgrass Region (PNWBR) with a long history of natural and anthropogenic ...Citation Citation
- Title:
- Canyon Grasslands of the Hells Canyon National Recreation Area : How have they changed over time and what is their future trajectory?
- Author:
- Pack, Samantha J.
The canyon grasslands of the Hells Canyon National Recreation Area (HCNRA) are a unique ecosystem within the Pacific Northwest Bunchgrass Region (PNWBR) with a long history of natural and anthropogenic disturbances including fire, invasive species introduction, historical livestock grazing, and cultivation. Even with this history, these canyon grasslands contain some of the last remnants of the Pacific Northwest Bunchgrass Region. For thousands of years, these grasslands were occupied by the Nez Perce Tribe and have been grazed since the 1700s. In addition to grazing, settlers cultivated many parts of the HCNRA and some of these homesteads can still be seen today. Both historical and current land uses are strongly influenced by the natural topography of these canyon grasslands, with the highest concentration of land use centered on benchlands while steep canyon slopes avoided cultivation and were used less by livestock. The different plant associations of these grasslands are also influenced by the unique topography of the HCNRA due to the relationships between soil moisture and depth and abrupt alterations in aspect, slope, and elevation. Very few studies have examined the plant associations of the canyon grasslands of the HCNRA, even fewer have asked how they have changed over time, and there are no studies looking into their future trajectory by assessing the seed bank. The first study in my thesis (Chapter 2) focused on how canyon grasslands have changed over time using a repeated survey of vegetation from four different plant associations within the Lower Imnaha Subbasin. From the original study conducted in 1981, a total of 19 different plots in four plant associations were chosen to be resampled in 2014. Since the original study was used to classify seral stages within the plant associations, these successional stages were used to determine if the plant communities had transitioned between the seral classes over the 33 year-time-period. In addition, given the importance of topography to these grasslands, elevation, slope, and aspect were evaluated for their relationship to successional changes. Both Nonmetric Multidimensional Scaling (NMS) and Indicator Species Analysis were used to verify the seral stage classifications for each plot in 1981 and 2014. To evaluate how each association had changed between sampling years, Multi-response Permutation Procedures (MRPP) and NMS were used. Most of these plant associations were relatively stable and had, for the most part, remained at the same seral stage or transitioned to a later seral stage. Among the plant associations, slope was the topographical variable that appeared most related to the transitions in seral stages. Steeper slopes either remained at the same seral stage or transitioned to a later one, while gentler slopes (< 20%) tended to shift from later to earlier seral stages. A relatively new introduced annual grass to the region, Ventenata dubia (not present in the 1981 sampling), was found in three of the four plant associations and was most abundant on the benchlands. The results of this resurvey suggest that topography is related to both the distribution of plant associations and which sites will shift in seral stage over time across the canyon grasslands of the Lower Imnaha Subbasin. The second study of my thesis (Chapter 3) focused on using a seed bank study as one of the many ways to examine the future trajectory of the plant communities in the canyon grasslands of the Lower Imnaha Subbasin, with a particular focus on the benchlands. The seed bank contains the regenerative pool for plant communities and represents the potential for a community to respond to disturbances. The seed bank from benchland sites in one plant association was evaluated in relation to the standing vegetation, successional stage, and historical cultivation. To my knowledge, this was the first seed bank study for the grasslands of this region. Vegetation cover and soil samples were collected from 8 sites, including two previously cultivated and two reference noncultivated sites. NMS was used to extract the strongest community gradients, which naturally separated out the seral stage classifications of the vegetation. To evaluate differences between the vegetation and the seed bank, between successional stages, and between cultivation histories, MRPP was used. Results from the seed bank study are consistent with many other studies around the world in perennial grasslands showing that the vegetation and seed bank are often dissimilar. Similarities between the vegetation and seed bank were highest in the annual grass dominated stage compared to the early seral stage. The effects of cultivation appear to still be evident in the seed bank, where cultivated sites have significantly more introduced grasses compared to noncultivated sites (p < 0.05). There was an overall greater abundance of introduced annual forb and grass species in the seed bank on these benchland sites, suggesting that they may be native seed limited and could easily shift to invasive species dominance after further disturbance, especially on previously cultivated areas. The results of both of these studies suggest that benchlands and lower sloped sites surrounding them in the canyon grasslands of the Lower Imnaha Subbasin may less resistant and resilient to disturbance. Priorities for future research and management may also need to focus on the plant communities of benchlands in these unique grasslands.
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379. [Article] The historic and contemporary ecology of western Cascade meadows : archeology, vegetation, and macromoth ecology
Montane meadows in the western Cascades of Oregon occupy approximately 5% of the landscape, but contribute greatly to the region's biodiversity. Western Cascades meadows are dynamic parts of the landscape ...Citation Citation
- Title:
- The historic and contemporary ecology of western Cascade meadows : archeology, vegetation, and macromoth ecology
- Author:
- Highland, Steven A.
Montane meadows in the western Cascades of Oregon occupy approximately 5% of the landscape, but contribute greatly to the region's biodiversity. Western Cascades meadows are dynamic parts of the landscape and have contracted by over 50% in the past two hundred years in the HJ Andrews Experimental Forest (hereafter Andrews Forest). Many studies have linked the loss of meadows with local extirpation of species and loss of regional biodiversity, but these processes depend upon the factors that create and maintain meadows, and how species respond to meadow configuration. The prehistory of these meadows is poorly understood, as is the contemporary ecology. This study combined previously collected archeological and moth datasets, aerial photographs, and new plant, tree core, and moth data to investigate interactions between landforms, disturbance, vegetation, and moth abundance and diversity in montane meadows of the western Cascades of Oregon. Burning by prehistoric people may have created and maintained montane meadows, but relatively little evidence remains of the activities of prehistoric peoples in the western Cascades. This study assessed the extent to which prehistoric people preferentially used different landforms and vegetation types by inferring use from landscape distributions of archaeological sites. Descriptions of 359 previously recorded and four newly discovered archeological sites in the McKenzie River watershed of western Oregon were examined using GIS and chi-square analysis to determine how sites were distributed relative to classified vegetation and landforms of the 3700-km² McKenzie River watershed. The high ridges of the HJ Andrews Experimental Forest were analyzed using air photo change detection and archaeological field surveys to identify how archeological sites were distributed relative to landforms and vegetation communities, including meadows. The field surveys documented physical evidence (archeological sites) confirming Native American use of the meadows and surrounding open forests. The locations of these sites indicate that Native Americans utilized the edges between large open meadows and open forests, as well as gently sloping open meadows. The prior extent of meadows (before air photos) was estimated by dendrochronology of 220 trees along present-day and inferred past meadow edges. Forest age structure and the open-grown forms of Douglas fir suggests a much more open habitat, potentially due to fire, was present more than 200 years ago. Moths are major consumers of vegetation when in caterpillar stage and are food sources for many birds and mammals, and contribute greatly to the insect diversity in a region. Moth species richness and abundance may be associated with the distribution of vegetation communities and seasonal timing, and the conservation of rare moths may depend on the conservation of rare vegetation habitats. A dataset of moths sampled 10 times/year at 20 locations in the 64-km² Andrews Forest over the period 2004-2008 was analyzed using generalized linear mixed models (GLMM), non-metric multidimensional scaling (NMS), multi-response permutation procedure (MRPP), analysis of variance (ANOVA), and two tailed t-test to identify the overall patterns of rare and common moth distribution as well as moth community relationships to structurally and taxonomically derived vegetation classes and seasonality. Five hundred fourteen species and 69,168 macromoth individuals were identified. Moth species abundance and diversity were significantly higher in low elevation coniferous forests than in other vegetation types, according to the GLMM. Sixty-six rare moth species were significantly associated with high elevation open habitats. Species associated with meadows also were significantly more likely to be hardwood or herb-feeders than conifer-feeders as caterpillars, based on ANOVAs. The 26 most common moth species were significantly associated with low elevation coniferous forests and were more likely to be conifer-feeders as caterpillars, based on ANOVAs. Common moth species were significantly more likely to emerge earlier in warmer years than in cooler years, based on a two-tailed t-test. Managing the western Cascades landscape for moth biodiversity and for moth abundance requires maintenance and potentially expansion of rare upland habitats as well as lowland coniferous forests. Montane meadows in the Andrews Forest are contracting in size, but it is not known how these changes have affected moth and plant biodiversity. The rate and pattern of meadow contraction from 1949 to 2005 along the high ridges of the Andrews Forest were analyzed using air photo change detection. Overall meadows contracted by nearly 50% from 1949 to 2005, but rates of meadow loss were much higher for the largest meadow complexes. Plant community diversity in seventeen meadows and the diversity, abundance, and community structure of moths at 98 locations sampled in the summers of 2008, 2009, and 2010 were related to measures of meadow size, isolation, and other variables using cluster analysis (CLA), MRPP, NMS, and generalized additive models (GAMs). Plant diversity in meadows was significantly positively related to meadow area in 1949 and the distance of the meadow from the road, based on GAM analysis. Plant community structure was most closely correlated with meadow area in 1949 and slope, based on CLA, MRPP, and NMS analysis. Calendar day explained the most variation in moth species richness, abundance, and community structure, but the next most important explanatory variables differed according to feeding guild, based on GAMs. Richness, abundance, and community structure of herb-feeding moths was related to meadow area in 1949 and elevation. For angiosperm-feeding moths, area-perimeter ratio in 2005 explained the most variation in richness, abundance, and community structure after calendar day. For gymnosperm-feeding moths, meadow area change from 1949-2005, a variable measuring the amount of increase in coniferous tree cover, explained the most variation in richness, abundance, and community structure after calendar day. The abundance and diversity of herb-feeding moths and meadow plants exhibited a lagged response to habitat loss, which may indicate an extinction debt. In contrast, angiosperm-and gymnosperm-feeding moths responded quickly (within 50 years) to increases in their habitat. Managing for the conservation of biodiversity in the upper elevations of the Andrews Forest will require targeted management strategies for different groups of organisms. Herb-feeding moths and meadow plants will benefit from expansion of open meadow habitat, while angiosperm and gymnosperm-feeders will require the maintenance of edge environments and coniferous forests.
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380. [Article] Predictability and Constraints on the Structure of Ecological Communities in the Context of Climate Change
Ecologists must increasingly balance the need for accurate predictions about how ecosystems will be affected by climate change, against the fact that making such predictions at the ecosystem-level may ...Citation Citation
- Title:
- Predictability and Constraints on the Structure of Ecological Communities in the Context of Climate Change
- Author:
- Barner, Allison K.
Ecologists must increasingly balance the need for accurate predictions about how ecosystems will be affected by climate change, against the fact that making such predictions at the ecosystem-level may be infeasible. Although information about responses of individual species to a changing environment is increasing, scaling such information to the community level is challenging. To date, predicting responses of ecological communities to climate change is constrained by limited theoretical and empirical knowledge about the response of communities and ecosystems to change. My dissertation addresses several knowledge gaps in our understanding of community structure under climate change. This research draws from a rich experimental tradition in the species-diverse model ecosystem of the US Pacific Northwest rocky intertidal to test ecological theory. In Chapter 2, I assessed whether the response of multiple species of coralline algae to global change could be predicted from basic first principles of chemistry, physiology, and ecology. Given the rate of global change, and the time-consuming process of experimentally determining species responses to climate change, I hypothesized that species can be grouped using existing theory, either by their evolutionary relatedness or by their ecological traits, such that climate responses are similar within a group. Such a scheme would greatly reduce the number of experiments needed to characterize species climate vulnerability, requiring the characterization of the response of groups of species to climate change, rather than individual species. Using a suite of five co-occurring species of intertidal articulated coralline algae (Corallina vancouveriensis, Corallina officinalis, Bossiella plumosa, Bossiella orbiginiana, and Calliarthron tuberculosum), I applied this framework to generate ten mutually exclusive hypotheses that could explain organismal response to ocean acidification, a consequence of global climate change that threatens marine calcifying species. I found that all species had similar responses to ocean acidification, and that responses were generally predicted by the body size of the individual. Despite the power that such a framework provides in understanding group-level response to climate change, predicting community-level response requires knowledge of how organisms affect one another. In Chapter 3, I quantified species interactions in a series of removal experiments to estimate the reciprocal effects between a canopy-forming intertidal kelp (Saccharina sessilis) and a suite of understory species that persist beneath the kelp canopy. This experiment was replicated in different oceanographic conditions across a large latitudinal gradient, as a step towards understanding how interactions might change with climate change. However, the experiment demonstrated that interactions between the canopy and understory were consistent among different environmental conditions. Furthermore, the strongest effect was that of understory species, particularly articulated coralline turf algae, on the canopy species. The coralline turf algae both facilitated the recruitment of the canopy species and buffered the canopy from abiotic stress during its adult life stage. Combining experimental results and observational surveys, a hypothesized interaction network for these species was constructed, highlighting the importance of direct and indirect species interactions in promoting species coexistence. A long-standing controversy in ecology is whether or not species interactions can be inferred from observational data, as opposed to from experimental tests. Although the rocky intertidal ecosystem is unique for its ease of experimental manipulation, quantifying species interactions experimentally is often difficult or impossible. As an alternative, many have turned to statistical methods to estimate species interactions from observational data, namely, from patterns in species pairwise co-occurrences. In Chapter 4, I examined these co-occurrence methods and their potential relationship to experimentally measured species interactions. I first used a suite of different co-occurrence methods to generate a set of predicted species interactions of macrophytes and invertebrates from observational surveys conducted in the rocky intertidal zone of Oregon. I then compared the predicted species interactions to the same pairwise species interactions determined experimentally and assembled from the literature. Overall, of the seven methods tested, each generated a different set of predicted species interactions from the same data, and all methods predicted interactions that did not match those in the experimental database. Thus, predicting species interactions from patterns in occurrence remains elusive. Importantly, much work remains to be done to understand the link between species co-occurrences and their actual interactions with one another on the landscape. A key limiting frontier in climate change ecology is determining the influence of species interactions on species distributions across the landscape, and the sensitivity of such interactions to changes in climate. Finally, in Chapter 5, I used theory from the published literature and knowledge from my previous chapters to make predictions the recovery of low rocky intertidal communities after a disturbance. The process of community development after disturbance has been studied in many ways, from the successional studies of the early 1900s, to modern community assembly theory. In recent years, a focus on the unpredictability of community assembly has emerged, paying particular attention to the role of historical contingency, or priority effects, in determining the recovery trajectory of a community. Priority effects occur when the arrival of a species after a disturbance inalterably changes the composition of the developing community, driving the assembly of widely different communities at a small spatial scale. I conducted a community assembly experiment in three different low intertidal zone community "types", each characterized by different dominant macrophyte species (Saccharina sessilis, Phyllospadix spp., and algal "turfs"). Replicating this experiment at six sites along the Oregon coast, I found that both regional and local dynamics constrain the recovery of communities after disturbance. Half of the time, the community returned to the state of the nearby community type. The remaining communities were influenced by priority effects that could be predicted based on 1) regional dynamics favoring some species over others, or 2) the timing of arrival of important facilitating species. Overall, understanding the dynamic relationship between the persistence of diverse communities and a changing environment remains one of the challenges of our time. My dissertation highlights some of the challenges in predicting the future composition of communities under climate change, but also provides some ways forward. Integration of experimental, theoretical, and observational studies builds the scaffolding of prediction, whereby understanding the constraints on species physiology, the interactions among species, and community assembly can help frame the context in which predictions are made.