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2541. [Article] Exploring the relationship between engineering design project characteristics and risk indicators
Engineering design projects are implemented to accomplish a variety of goals in organizations. As the complexity of each project grows, the risk and uncertainty accompanying each project increases as well. ...Citation Citation
- Title:
- Exploring the relationship between engineering design project characteristics and risk indicators
- Author:
- Yim, Rachel L.
Engineering design projects are implemented to accomplish a variety of goals in organizations. As the complexity of each project grows, the risk and uncertainty accompanying each project increases as well. As a result project managers must identify potential risks to projects and create plans to avoid realized risks leading to project failures. A risk indicator is a set of circumstances that are indicative of the strong likelihood of a risk event occurring during a project. This research was created to explore the relationship between risk indicators and various project characteristics, including project classification (the type of business goals the project was created to fill) and project type (whether the project was a first or a second attempt to solve an engineering design problem). The results of this research are applicable to engineering managers who are responsible for the successful completion of design projects. The research questions addressed in this study were: 1) Is there a difference in the frequency of occurrence between the 36 risk indicator codes? 2) If there is a difference, in the risk indicator frequencies, which risk indicator codes occur most often? 3) Which risk indicator codes are the most prevalent in association with certain project characteristics? These research questions were explored with the intent of discovering the risk indicators that are most important for project managers to consider in creating risk management plans based upon project characteristics. The goal of this research is to contribute to the project management body of knowledge and to provide insight into the nature of the relationship between various project characteristics and risk indicators. To achieve this objective, eleven medium-complexity engineering design projects were selected for study. Two interview protocols were developed to elicit information about critical events occurring during the life cycles of these engineering design projects. Employees from a variety of job functions, who were directly involved in the selected projects, were interviewed. Multiple researchers coded transcripts created from the interviews. Researchers used a code scheme, developed from the literature on project success factors. The text from interview transcripts was analyzed to identify similarities and differences in the frequencies of different risk indicator codes for different project characteristics. Frequently occurring risk indicators were noted and implications for project managers were identified. The projects were divided into groups with similar project characteristics. Differences in the rates of occurrence of risk indicators were used to identify risk indicators, based on these specific project characteristics. Similarities and differences in the rates of occurrence of risk indicators in the different groups of projects were analyzed for emergent themes. The results provided strong evidence for significant differences in the frequency of occurrence for risk indicators based on project characteristics. The most frequently occurring risk indicators differed for three project classifications (strategic, compliance, and operational). The most frequently occurring risk indicators also differed for original and rework projects. Nonparametric statistical tests were also applied to the data to test between significant differences across all risk indicators, using the same project characteristics. Communication challenges were prevalent for all types of projects. Research has shown that inadequate communication can cause time and cost overruns on projects and can lead to rework projects. The types of communication challenges that were the most frequent differed between project classifications. For compliance projects, the most predominant communication risk was between the organization and suppliers. Communication risks between the organization and the customers occurred most often in operational projects. Finally in strategic projects, the most frequently occurring risks to communication occurred internally, between different business and engineering groups within the organization. Another important theme was the need for standard procedures to provide adequate documentation to the different groups involved in projects. Risks associated with a lack of information provided to the different business and engineering groups working together on projects, were common among all projects. Many interviewees suggested the need for standard procedures to provide all necessary information to all groups assigned to each project, in order to facilitate the coordination of the work. A lack of up front planning was detrimental for both original and rework projects. A lack of up front planning in original projects, at times, resulted in project failure, thereby creating the need for a rework project. In rework projects, planning at the beginning of a project was sometimes rushed due to the urgency of the project, thereby causing additional risks to the success of rework projects later on in the project life cycle. Project managers can use the findings from this research to create more effective risk management plans tailored to the characteristics of a particular project. Knowledge of the risk indicators with the highest frequency of occurrence in each type of project can direct managers to the most effective use of risk management resources. The results of this research also add to the project management body of knowledge and provide a deeper understanding of the relationship between project characteristics and specific risk factors. The results also provide evidence that the project classification and project type are important determinants of the types of risks that will likely be faced in the course of a project. The approach used for this study can be applied to other industries and other types of projects to further extend the understanding of the relationship between project characteristics and risks. While there was evidence that some risks are typical to all design projects, a larger study is needed to generalize these findings beyond design projects and beyond the engineering organization studied.
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2542. [Article] Breeding an open pollinated broccoli for organic production systems using participatory methods
Organic agriculture is an important and growing sector of U.S. and world food production. Consumers are increasingly aware of and interested in the production practices and impacts associated with agriculture ...Citation Citation
- Title:
- Breeding an open pollinated broccoli for organic production systems using participatory methods
- Author:
- McKenzie, Laurie R.
Organic agriculture is an important and growing sector of U.S. and world food production. Consumers are increasingly aware of and interested in the production practices and impacts associated with agriculture and as such, are showing a preference for sustainably produced, raised, and harvested foods. In order to continue to meet the growing demand for organic produce, organic growers need cultivars that are optimally adapted to organic and low input conditions. Quality seed is the foundation of any functional and stable farming system. Unfortunately the lack of organically bred and produced seed is hindering the continued growth and success of organic farming. Meeting the needs of the organic sector has been a challenge for the seed industry; it is an industry that often doesn't understand the specific and unique requirements associated with the diversity of environmental and market demands of organic systems. However, organic farmers and the organic food systems they supply, require a robust organic seed system that is appropriately adapted to regional agronomic challenges and market needs, meets standards and regulations, and encompasses the social and ecological values of organic agriculture. One plausible approach to meeting the cultivar and seed needs of organic and low input production systems is through the use of participatory plant breeding (PPB). PPB is a collaborative approach for identifying and developing genetically diverse plant material and varieties involving partnerships among formal sector breeders and researchers, farmers, extension agents, educators, and end users. Participatory plant breeding fundamentally changes the way that formal breeding programs and farmers manage germplasm and plant genetic resources. Typically, formal breeding programs restrict access to germplasm and breeding materials and only supply farmers with finished varieties. In PPB, farmers are involved in the early stages of creation and evaluation of germplasm and breeding material, and stay engaged with the breeding process until new varieties are created. PPB is an excellent model for breeding specifically for organic systems because organic systems in developed countries have many similarities to low-input agricultural systems in the developing world. Some of these parallels include heterogeneous growing environments, a wide range of end uses and marketing strategies, lack of suitably adapted and/or derived varieties, lack of attention from the formal seed sector, and a reduced reliance on synthetic inputs (compared to conventional systems). Breeding for organic systems is a relatively young field and breeders in the formal sector do not have a good handle on what traits are important for robust production under organic conditions. Thus the opportunity to meld farmers' experience and knowledge with breeders' expertise is an effective way to breed for organic production systems. The purpose of this project was to investigate and explore the opportunities and challenges of organic plant breeding using participatory research methods. This research had three goals: 1) to develop an open pollinated broccoli with contemporary quality traits for organic production systems using participatory strategies; 2) to compare broccoli selections made by formally trained plant breeders and farmer breeders; and 3) to capture the stories and experiences of the formal breeders and farmer breeders involved with this broccoli material in order to contribute to the growing wealth of knowledge on collaborative and organic breeding work. The Oregon State University Vegetable Breeding Program made significant progress towards decreasing the variability of the broccoli project material through three successive years of modified half-sibling selections. Evaluations and selections were based more strongly on quality traits rather than soley on production traits such as yield. Although progress was incremental and statistically verified in only three out of the fifteen quality traits, we observed trends in the data indicating progress towards an increasingly uniform, stable, and reliable open pollinated broccoli with specific adaptation for organic production systems. There were very few differences between broccoli materials developed by formally trained plant breeders and farmer breeders. This was especially true for the three cultivars developed in the Pacific Northwest (PNW) (one in Washington and two in Oregon). The 'East Coast' population, which had been collaboratively selected by formal and farmer breeders in New York, expressed significantly distinct differences from the PNW materials. When the farmer breeder and formal breeder materials were pooled together and compared to pooled check cultivars they expressed significant differences for nearly all traits across all years. This demonstrated that all of the collaboratively developed open pollinated materials are distinctly different from the F1 hybrids currently available. Our work has demonstrated a few of the myriad of positive outcomes achievable with the use of participatory plant breeding for organic production systems. The participatory nature of this project resulted in increased confidence and feelings of empowerment for all involved. Both farmers and breeders felt their involvement was socially beneficial and widened their networking and seed community circles. The farmer-bred cultivar 'Solstice' is now available as a result of Jonathan Spero's work, and a cultivar tentatively named 'Benton' is about to be released for sale through Oregon State University. Our results agree with previous study findings that formal and farmer breeder selections are often not distinctly different; thus providing evidence for continuing to support the involvement and education of farmers in plant breeding, especially in reference to organic production systems. This study demonstrates the potential of collaboratively developed and farmer-bred cultivars to become viable and vibrant open pollinated alternatives to the current open pollinated cultivars on the market today.
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The purpose of this study was to determine the readability of three series of selected fourth, fifth and sixth grade social studies textbooks, a total of nine textbooks. Two measurements were utilized: ...
Citation Citation
- Title:
- The readability of selected fourth, fifth and sixth grade social studies textbooks as determined by the Fry Readability Graph and group informal reading inventories
- Author:
- Pruitt, Janet Louise McCracken, 1930-
The purpose of this study was to determine the readability of three series of selected fourth, fifth and sixth grade social studies textbooks, a total of nine textbooks. Two measurements were utilized: a readability formula (Fry Readability Graph; Knapp, 1971), and group informal reading inventories. The Fry Graph was applied to ten randomly selected 100-word passages in each text; proper nouns were included in the computations. The group informal reading inventories were constructed from the same textbooks on passages not previously taught. The tests were administered in May to 1467 students in 70 randomly selected classrooms. Procedures Both descriptive and inferential statistics were used to analyze the data. Readability levels derived by the application of the Fry Graph were reported for each text:, as was the range of readability within each text and the deviation of each sample from the overall readability of the textbook. The test scores from the group informal reading inventories were first reported in terms of the per cent of subjects scoring at the independent level (90, 95, 100 per cent), the instructional level (65, 70, 75, 80, 85 per cent) and the frustration level (60 per cent or lower) for the sample. Mean test scores were also computed for the sample, the urban and rural subsets, for each grade level, and for each publisher. To determine if there were significant differences among the subsets, the following null hypotheses were formulated: H1 There are no significant differences in the mean scores of the urban and rural subjects. H2 There are no significant differences in the mean scores of the subjects in grades four, five and six. H3 There are no significant differences among the mean scores of the subjects tested on the D. C. Heath, the Silver Burdett or the Benefic Press social studies series. The differences among groups were statistically analyzed at the .05 and .01 levels of significance by the pooled variance t-test or by the analysis of variance. When the analysis of variance resulted in a significant F value, the multiple range test was applied to determine the exact location of the mean difference. Findings of the Study Fry Readability Graph 1. Two textbooks, the fourth grade textbooks published by D. C. Heath and by Silver Burdett, had readability levels in agreement with the publishers' designated grade level. The remaining seven textbooks had readability levels one to four years above the designated grade level. 2. The average range of readability within the textbooks was 6.2 years with little evidence of a gradation from less difficult to more difficult reading material. 3. When the three series were ranked according to their relative difficulty on the basis of the Fry readability levels, it was determined that: a. The D. C. Heath series is the least difficult. b. The Silver Burdett series occupies an intermediate position. c. The Benefic Press series is the most difficult. Group Informal Reading Inventories 1. For the total sample 9.41 per cent of the subjects scored at the independent level, 32.04 per cent scored at the instructional level, and 58.55 per cent scored at the frustration level. The mean test score was 54.82 per cent. 2. The mean score (56.64 per cent) of the urban subjects was significantly higher (.01 level) than the mean score (52.35 per cent) of the rural subjects with a t value of 3.30. H1 was rejected. 3. The mean score for grade four was 50.35 per cent; for grade five, 53.96 per cent; and for grade six, 58.09 per cent. The analysis of variance resulted in a significant (.01 level) F value of 11.25. H2 was rejected. 4. The mean scores by publisher were: D. C. Heath, 55.88 per cent; Silver Burdett, 55.77 per cent; and Benefic Press, 50.38 per cent. The analysis of variance resulted in a significant (.01 level) F value of 5.47. The multiple range test showed significant differences between the Benefic Press and D. C. Heath series (.01 level) and between the Benefic Press and Silver Burdett series (.01 level). There were no significant differences between the D. C. Heath and Silver Burdett series. H3 was rejected. Implications 1. The findings of this study did not differ in any substantial way from the results reported by earlier investigators. Further studies of the readability of social studies textbooks similar in content to the three series analyzed in this investigation is not warranted. 2. Additional research is needed to determine if systematic instruction resembling the procedures prescribed for a well-developed basal reading lesson will significantly affect the ability of students to comprehend social studies textbooks. Recommendations 1. Current knowledge regarding the nature of concept development should be a major consideration for curriculum decisions in the social studies. Piaget's findings regarding the cognitive functioning of elementary school students provide insight regarding the capabilities of this age group. 2. Instructional alternatives that diminish heavy reliance on the textbook should be afforded a fair trial in the classroom, e.g., simulation and gaming (Cuetzkow, 1962; Inbar, 1972), process analog (Fielder, 1967; Joyce, 1972), role playing (Shaftel, 1967), problem solving (Fenton, 1967; Shaftel, 1967), inquiry approaches (Suchman, 1964; Clements, Fielder, Tabachnick, 1966), and inductive development of concepts and generalizations (Taba, 1966; Fenton, 1966; Hanna, 1965). 3. A publicly financed agency staffed by expert analysts and equipped with the necessary resources should be established to provide analysis services to publishers and to determine the difficulty level of all instructional materials as they appear on the market (Bormuth, 1971). 4. Pilot editions of all new textbooks should be field tested with a cross section of students using procedures similar to those utilized by the publishers of standardized tests. 5. When classroom teachers make reading assignments in social studies textbooks, they should faithfully adhere to the same procedures that are prescribed for a well-developed basal reading lesson.
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Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within ...
Citation Citation
- Title:
- Coral-reef fishes : insights into larval dispersal and invasion ecology
- Author:
- Pusack, Timothy J.
Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within general ecology, fisheries biology, and conservation biology. The primary goal of this dissertation was to use the coral-reef fishes system to investigate two pressing sets of issues that face marine ecologists and managers of living marine resources. The first topic is the spatial and temporal patterns of larval dispersal and reproductive success in a marine metapopulation (Chapter 2). Because miniscule larvae are difficult to track in the vast pelagic environment, little is known about the patterns of larval dispersal. Yet, the more that is understood about the spatial and temporal variability in larval dispersal, the easier it will be to identify sites that are self-sustaining and exporting larvae to unprotect sites, a common goal of marine reserves. Incorporating this information into siting of marine reserves will improve their effectiveness. The second topic is fundamental in the ecology of biological invasions: species specific interactions between an invasive predator and native species. Specifically, I investigated the ability of an invasive predator to disrupt natural population regulation of a native prey species (Chapter 3), and the ability of a native predator to provide biotic resistance against the invasive species (Chapter 4). Because management of the lionfish invasion is needed throughout the Caribbean and Atlantic waters, it is necessary to understand not only how lionfish can change the native system, but also potential ways to moderate the negative effects. To address the first topic, we collected a total of 3,278 genetic tissue samples from bicolor damselfish (Stegastes partitus) over a four year period from reefs near four islands that encompass Exuma Sound, Bahamas (Chapter 2). Using a Bayesian parentage analysis, eight parent-offspring pairs were detected, which directly documented both connectivity between and self-recruitment on an ecological time scale. Remarkably, some larvae returned to the exact same reef where they were spawned, while others traveled to sites greater than 100 km distance. The only study island without a detected parent-offspring pair, Lee Stocking Island, was also the island that showed the most restrictive gene flow on evolutionary time scales. Additionally, variability was documented in the spatial and temporal signatures of sweepstakes reproduction and Wahlund effects. The variation we observed may be influenced by seasonal mesoscale gyres present in Exuma Sound, which play a prominent role in shaping local oceanographic patterns. Understanding how to identify pathways of larval dispersal is important to designing networks of marine reserves, because a common goal of reserves is to protect populations that are self-seeding and can export larvae. Thus, this research not only demonstrates that temporal variability is a prominent characteristic of larval dispersal, but provides an example of how to identify these populations. To address the second topic, two studies using both lab observations and manipulative field experiments were conducted to study the interaction between invasive Indo-Pacific red lionfish (Pterois volitans) and two different native species. In the first study (Chapter 3) three different data sets were used to document the effect of lionfish predation on their top prey species, the bridled goby (Coryphopterus glaucofraenum). The first data set was extracted from three previous studies to compare the change in abundance of bridled goby between patch reefs with lionfish and patch reefs that were predator-free. The second data set came from laboratory feeding trials to test for the presence of a size refuge for bridled goby caused by lionfish gape limitation. The third data set came from a manipulative field experiment using 22 nearshore reefs where the per capita mortality of bridled gobies was compared among four orthogonal predator treatments: (1) predator-free control, (2) a single native predator only -- the graysby grouper (Cephalopholis cruentatus) -- representing the pre-invasion system, (3) a single lionfish only, and (4) one native grouper and one lionfish, representing the invaded system. The combined results from these three data sets demonstrated that lionfish can consistently consume a significant amount and an extremely high proportion of bridled goby on small patch reefs. While small lionfish cannot eat bridled goby larger than 0.42 times their body size, large lionfish eat virtually the entire size range of bridled goby. These findings indicate that lionfish have the potential to extirpate local goby populations. In the second experiment, lionfish were exposed to different abundances of a native grouper, the Nassau grouper (Epinephelus striatus), on 28 nearshore patch reefs in the Bahamas. Lionfish persistence and growth was monitored over 10 weeks, as well as the abundance of small, < 5 cm total length (TL), native reef fishes. Nassau grouper did not affect lionfish persistence or growth. Yet, reefs with a lionfish and many Nassau grouper saw a significant increase in the abundance of small reef fishes compared to reefs with only lionfish or lionfish with few grouper. Thus, it appears that high densities of Nassau grouper provide some biotic resistance on Bahamian patch reefs by potentially interfering with lionfish predation on native fishes, perhaps by interrupting stalking behavior. This dissertation highlights the flexibility of the coral-reef fishes system for investigation of broadly different topics in basic and applied ecology. Coral-reef fishes are a tractable system for both large and small scale studies, as well as laboratory observations and manipulative field experiments. The findings of this dissertation advance the understanding of metapopulation dynamics and have implications for fisheries management and marine reserve design. This research also documents further evidence of the negative effects of lionfish, yet provides some promising findings that may indicate some native biotic resistance to this devastating of marine invasions.
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Understanding the maintenance of sexual systems is of great interest to evolutionary and ecological biologists because plant systems are extremely varied. Plant sexual systems have evolved to include not ...
Citation Citation
- Title:
- Spatial Segregation of the Sexes in a Salt Marsh Grass Distichlis spicata (Poaceae)
- Author:
- Mercer, Charlene Ashley
- Year:
- 2010
Understanding the maintenance of sexual systems is of great interest to evolutionary and ecological biologists because plant systems are extremely varied. Plant sexual systems have evolved to include not only complete plants with both male and female reproduction occurring on one plant (i.e., monoecious and hermaphroditic) but also plants with male and female function on separate plants (dioecious). The dioecious reproductive system can be used to test theories on niche differentiation given that having separate plants potentially allows for the exploitation of a broader niche. This increase in the realized niche is due to the ability for separate sexes to occupy different niches, which may occur in different physical habitats. Some dioecious plants have been shown to occur in areas biased to nearly 100% male or nearly 100% female, called spatial segregation of the sexes (SSS). Occupying a broader niche could increase fitness in some species when the separation is used for one sex to gain access to resources that increase reproductive success and/or if the separation inhibits deleterious competition. These two mechanisms have been previously proposed for the evolution of SSS in dioecious plants. The first mechanism suggests that males and females have evolved to occupy different niches due to differences in reproduction (sexual specialization). The hypothesis for the sexual specialization mechanism is that females should have higher fitness in female-majority sites and males should have higher fitness in male-majority sites. The second mechanism states that males and females occupy different niches due to competition between the sexes (niche partitioning). The hypothesis for niche partitioning states that inter-sexual competition should decrease fitness more than intra-sexual competition. These mechanisms are not mutually exclusive. In our research we use the salt-marsh grass Distichlis spicata as our study species because this plant is dioecious and because molecular markers have been developed to determine the sex of juvenile plants. These molecular markers are important for testing the niche partitioning hypothesis for SSS in juveniles. Furthermore, previous work in California has shown that plants occur in areas nearly 100% female and nearly 100% male called spatial segregation of the sexes (SSS). The previous research also showed that female-majority sites were higher in soil phosphorus than male-majority sites. We conduct all research, presented in the proceeding chapters, on Distichlis spicata in the Sand Lake estuary near Pacific City, Oregon and in the laboratory at Portland State University. In Chapter 1 we used field data to answer two questions: (1) Does Distichlis spicata exhibit SSS in Oregon, and (2) If SSS is occurring, do differences occur in plant form and function (sexual specialization) in reproductive female and male plants in female-majority and male-majority sites? We used a sex ratio survey and collected field data on reproductive males and females. Our results show that there are female-majority and male-majority areas and SSS is occurring in the Sand Lake Estuary. Results from our native plant data suggest that reproductive females perform better in female-majority sites compared to male-majority sites which could suggest that sexual specialization is occurring in females. We currently have a long term field reciprocal transplant experiment in place to further address this hypothesis. In Chapter 2 we use field dada to address the following questions: (1) Does site-specific soil nutrient content occur in August, when females have set seed? (2) Does sex-specific mycorrhizal colonization occur in reproductively mature plants? (3) Does sex-specific mycorrhizal colonization vary seasonally in natural populations? Inside the roots of D. spicata a symbiotic relationship is formed between plant and arbuscular mycorrhizal fungus (AM). The AM- plant relationship has been shown to thrive in phosphorus limited areas because the mycorrhizal fungus increases nutrient access to the plant. We analyzed the results of the field soil nutrient content and mycorrhizal colonization in roots of native Distichlis spicata from male-majority and female-majority sites. The root colonization included staining roots with trypan blue and viewing sections of the roots under the microscope. Our results show that female- majority sites are higher in phosphorus and are found to have higher AM colonization than male- majority sites in the field. In Chapter 3 we then reciprocally transplanted D. spicata plants in the field to address the following questions: (1) Does niche partitioning occur in D. spicata, and (2) If niche partitioning is occurring, which plants are competing more? Our reciprocal transplant experiment included seeds grown in intra-sexual, inter-sexual and no competition in cones, planted directly into the field, and allowed to grow for 15 months. After the 15 months was over we measured survival, dry weight and root/shoot ratio. The design of the experiment was to determine the effects of competition (intra-sexual and inter-sexual) and no competition on (single male and female) on survival, biomass and root/shoot ratios. Our results show that niche partitioning is occurring and plants in inter-sexual competition have significantly less biomass then intra-sexual competitors. In, Chapter 4, we conduct a laboratory experiment to address the following questions: (1) Do plants show plasticity in their response to root exudates of the competing plant in regards to the sexual phenotype of the competitor? (2) Do plants show plasticity in their response to root exudates of the competing plant with respect to the relatedness of the competitor? We use sterile seeds grown in 24-well plates containing liquid media. For each competing plant, we picked plants up out of the wells and into the competing plants wells so that plants only experienced media that the competing plant had grown. At no time do roots ever come into contact with one another. We measured primary root length, number of lateral roots, the number of root hairs, root/shoot ratio and total dry weight. We analyzed the study two different ways, one for sexual type competition (inter-sexual, intra-sexual, none) and for plant relationship (KIN, STRANGER and OWN). The results for the sexual type competition found that inter-sexual competition was greater for root/shoot ratio and dry weight. The results for plant relationship competition found that kin plants had a significantly greater number of lateral roots and a significantly longer primary root. The last chapter, Chapter 5, includes a summary of our conclusions. Our study found SSS occurring in the Sand Lake Estuary in Oregon with female-majority sites higher in phosphorus and root colonization higher in percent colonization of arbuscular mycorrhizal fungi compared to male-majority sites. Based on the sexual specialization hypothesis as a mechanism for SSS, we found that females had greater fitness in female-majority sites compared to male-majority sites, suggesting that sexual specialization is occurring in reproductive females. We then tested the niche partitioning hypothesis for SSS, and we found consistent lab and field results suggesting that niche partitioning due to inter-sexual competition is an explanation for why females and males D. spicata plants spatially segregate themselves at the juvenile life history stage. Furthermore, we found that plants that have the same mother had a significantly greater number of lateral roots and a significantly longer primary root. These results suggest that KIN plants respond differently to one another compared to plants paired with a plant not from the same mother (STRANGER) or when the plant is alone (OWN).
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Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); ...
Citation Citation
- Title:
- The geology of the Elk Mountain-Porter Ridge area, Clatsop County, northwest Oregon
- Author:
- Goalen, Jeffrey Scott
Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); Smuggler Cove formation (informal); Wickiup Mountain and Cannon Beach members (both informal) of the Astoria Formation; the Grande Ronde Basalt, and Frenchman Springs Member of the Wanapum Basalt, both of the Columbia River Basalt Group. Also, areally limited, unnamed sedimentary strata interbedded between flows of the Columbia River Basalt Group crop out in the study area. Quaternary deposits consist of alluvium, colluvium, and landslide debris. Rhythmically-bedded, foram-bearing, carbonaceous to micaceous mudstone and graded, fine-grained, feldspathic turbidite sandstone are the dominant lithologies of the upper Eocene (Refugian) Sager Creek formation. Plane-laminae and climbing ripple-laminae typical of Bouma b,c, and d intervals are common in the thin turbidite sandstone beds. Contemporaneous, rare, thick, sandstones may represent submarine feeder channels that supplied the more widespread, thinly-bedded overbank turbidite sandstones. Foraminiferal paleobathymetry indicates that deposition was in bathyal water depths. Sager Creek deposition was followed by a regression or offlap of the late Eocene to early Oligocene (Refugian) sea as indicated by the molluscan fossils and thick, bioturbated sandstone of the predominantly shallow-marine Pittsburg Bluff Formation. The lower part of the formation consists of outer shelf, glauconitic, fossiliferous sandstone and subordinate mudstone. Higher in the section are middle-shelf, fine-grained, bioturbated, tuffaceous, arkosic sandstones. These sandstones contain minor glauconite, wave- and storm-generated molluscan shell hash beds, carbonized wood fragments, and calcareous concretions. Deposition occurred in 20 - 50 m open-marine shelf water depths; however, the depositional environment may have shallowed to a bay-like setting (Moore, 1982, written communication). The upper part of the unit consists of thin- to medium-bedded, carbonaceous siltstone and mudstone with minor ashfall tuffs. Therefore, deposition of the Pittsburg Bluff Formation occurred as a shallowing-upward, then deepening depositional episode, punctuated by contemporaneous, intermittent eruption of nearby calc-alkaline western Cascade volcanoes. The deep-marine Oligocene to lower Miocene (Zemorrian to Saucesian) Northrup Creek formation is predominantly composed of thinly-laminated mudstone interbedded with thin, very fine-grained, graded, micaceous arkosic sandstone. Bouma c-d-e and a-b-e sequences are common in the turbidite sandstone; Bouma a-e intervals occur locally in sandstone/mudstone couplets. Paleocurrent indicators suggest that the predominant transport direction of these turbidite deposits was northeast to southwest. Abraded, carbonaceous plant debris and mica are abundant in the sandstone laminations. The upper part of the formation consists of thick, mollusk-bearing, moderately- to well-sorted, arkosic sandstone and minor polymict grit beds. A shallowing-upward, high-energy, shallow-marine shelf environment of deposition is indicated for the upper part of the formation. Contemporaneous with shelf and slope deposition of the Sager Creek, Pittsburg Bluff and Northrup Creek formations, the deep-water late Eocene to early Miocene Smuggler Cove formation was deposited as a distal or lateral correlative in a low-energy, outer shelf to slope setting. This foram-bearing unit consists of thick, bioturbated, bathyal, tuffaceous mudstone and siltstone with minor thin- to thick-bedded ashfall and current-reworked tuff. A marine onlap is indicated by the conformable relationship between the upper sandstone unit of the Northrup Creek formation and the overlying Smuggler Cove formation in the eastern part of the thesis area. The overlying lower to middle Miocene Astoria Formation contains two members in the thesis area: a high-energy, shallow shelf, fine- to medium-grained, fossiliferous, micaceous arkosic sandstone (Wickiup Mountain member), and an overlying, thinly-laminated, deepmarine mudstone (Cannon Beach member). Diatom floras indicate that a thermal "oceanographic irregularity" (water warmer than normal) may have occurred during deposition of the Cannon Beach member. At least six, and possibly eight, flows of the middle Miocene Grande Ronde Basalt (Columbia River Basalt Group) are present in the thesis area. Individual flows have been ascribed to the (N1?), R2, and N2 magnetozones. Geochemically, the flows consist of low MgO high Ti02, low MgO low Ti02, and high MgO subtypes. These subaerial to submarine flows are correlated to Mangan and others (1986) chemical subtypes 2D, 5C, 5A, and 4A of the Columbia Plateau-derived Grande Ronde Basalt of eastern Washington and eastern Oregon. The correlations are based on similarity of age, major element chemistry, stratigraphic position, and magnetic polarity. Field evidence suggests that thick, submarine pillow and breccia complexes generated sufficient pressure to autoinvasively inject into the Eocene to middle Miocene sedimentary strata of the Plympton/Porter ridge and Elk Mountain areas. This process apparently formed many randomly-oriented dike- and sill-like intrusions in the western part of the thesis area. However, in the eastern and central parts of the thesis area, three sub-parallel dikes (the Northrup, Beneke, and Fishhawk Falls dikes) extend along linear trends for tens of kilometers. This suggests that their emplacement was, in part, influenced by earlier or contemporaneous regional tectonism. At least two, and as many as five, flows of the Frenchman Springs Member of the Wanapum Basalt occur in the thesis area: one to two abundantly plagioclase-phyric Basalt of Ginkgo flow(s), and one to three Basalt of Sand Hollow flows (terminology after Beeson and Tolan, 1985). These flows consist of subaqueous pillow palagonite breccia and vesicular, columnar-jointed, subaerial basalt. No Frenchman Springs flows are invasive in the thesis area. Local middle Miocene sedimentary interbeds between flows of Grande Ronde and Frenchman Springs Basalt are lithologically and sedimentologically diverse. Common lithologies are fine- to mediumgrained, arkosic sandstone, coarse-grained basaltic sandstone, and structureless mudstone. Depositional environments represented by these strata are fluvial, marginal-marine, and shallow-marine. Thicknesses of individual interbeds range from 0.2 to 50 m. The thesis area is located on the northwest flank of the Oregon Coast Range anticline, adjacent to the Nehalem Arch. Large-scale northeast-trending oblique to strike-slip left-lateral faults coupled with northwest-trending oblique to strike-slip right-lateral faults dominate the structure of the area. These faults may have formed as conjugate shears (Riedel shear) caused by north-south compressive stress related to the oblique subduction of the Juan de Fuca Plate beneath the North American Plate. Five episodes of deformation are suggested by faults, dike orientations, unconformities, and other geological relationships within the thesis area: a late Eocene north-south compressional episode, an early Oligocene to early Miocene uplift, a middle Miocene northwest-southeast extensional episode, a post-middle Miocene to Pliocene (?) north-south compressional episode, and a north-south extensional event that occurred between the post-middle Miocene and Recent. Although crushed rock (for road and revetment construction) is currently the primary mineral resource within the thesis area, several potential fault traps on this northwest flank of the Nehalem Arch may contain significant reserves of natural gas. This conclusion is based upon field, laboratory, and subsurface (well) data. The Clark and Wilson sandstone of the middle to late Eocene Cowlitz Formation, the producing unit at the nearby Mist gas field, represents the most attractive target horizon. Additionally, the porous and permeable upper sandstone unit of the Northrup Creek formation could contain shallow hydrocarbon reserves beneath the northern part of the area.
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2547. [Article] Identifying factors driving sensitivity to fragmentation in forest breeding songbirds
Habitat loss and fragmentation are the greatest threats to biodiversity worldwide. Fragmentation impacts landscape configuration, resulting in a larger number of patches that are smaller in size and further ...Citation Citation
- Title:
- Identifying factors driving sensitivity to fragmentation in forest breeding songbirds
- Author:
- Valente, Jonathon J.
Habitat loss and fragmentation are the greatest threats to biodiversity worldwide. Fragmentation impacts landscape configuration, resulting in a larger number of patches that are smaller in size and further apart from one another. Island biogeography and metapopulation theory predict populations in these remnant patches should be smaller, have higher extinction rates, and be less likely to receive immigrants from other populations. However, empirical data frequently do not conform with these theoretical predictions, leading to assertions that this model is too simplistic to describe distributions and dynamics of fragmented populations. However, others believe that landscape configuration effects have been poorly tested and modeled to date. In this dissertation, I use breeding bird data collected in a fragmented forest landscape to explore this lack of congruence between theory and reality. I first test the hypothesis that heterogeneity in the detectability of mobile species due to temporary emigration from sample sites can produce biased estimates of metapopulation rates. Next, I test for idiosyncrasies in the effects of forest loss and fragmentation on species belonging to different ecological trait groups. Lastly, I examine whether fragmentation actually reduces the functional connectivity of landscapes for species identified as fragmentation-sensitive. Dynamic occupancy models are popular for estimating metapopulation dynamic rates (colonization and extinction) from repeated presence/absence surveys of unmarked animals. This approach assumes closure among repeated samples within primary periods, allowing estimation of dynamic rates between these periods. However, the impact of temporary emigration (reversible changes in sampling availability) on dynamic rate estimates has not been tested. In Chapter 2, I use simulated data to investigate the degree to which temporary emigration could mislead researchers interested in quantifying metapopulation rates. I then compared results from three avian point count datasets to evaluate the likelihood that temporary emigration confounds estimates of dynamics for 19 species under a popular sampling protocol. Simulated experiments indicated that when secondary periods were open to temporary emigration, presence of dynamics was identified ≥ 95.1% of the time, and dynamic rate estimates were accurate. However, dynamic rates were biased when secondary periods were closed to temporary emigration. In empirical datasets, dynamic occupancy models had greater support than closed models for all species when secondary sampling periods occurred in immediate succession (i.e., 3 samples within 10 minutes); however, my results suggest that this is because these estimates were heavily influenced by temporary emigration. When counts within a primary period were separated by 24-48 hours, I found evidence of dynamics for less than half of these species. I recommend an alternative sampling approach that allows accurate estimation of dynamic rates when temporary emigration is of no interest, and introduce a novel model for estimating both processes simultaneously in rare cases where they are both of biological interest. Concern for violating the occupancy modeling closure assumption has led to widespread recommendations that samples within primary periods be conducted extremely close in time. However, these results indicate this is not the best approach when interest is in quantifying dynamic rates. While dynamic occupancy models provide estimates of ‘colonization’ and ‘extinction,’ these values do not inherently represent dynamics unless temporary emigration has been explicitly modeled or accounted for with sampling design. Naivete to this fact can result in incorrect conclusions about biological processes. While theory predicts that fragmentation should negatively influence biodiversity, empirical support of this idea is weak in terrestrial systems. However, tests of fragmentation effects are typically confounded with landscape composition and potentially obscured by imperfect detection. In Chapter 3, I used multi-species occupancy models and a mensurative experimental design to test competing hypotheses about how forest fragmentation influences distributions of breeding forest bird species and communities. During the breeding seasons of 2011-2013, we recorded over 80,000 bird detections in 202 forest fragments using a sampling design that isolated the effects of patch size per se from the effects of forest amount (2 km), edge, local vegetation, and sample area. I modeled the effects of these covariates on distributions of individual species categorized by ecological trait groups (i.e., forest, forest interior, or forest edge). Though my results indicated little effect of patch size on total species richness, increasing patch size tended to have a positive effect on interior species, and a negative effect on edge species. The effects of total forest amount were much more variable, and actually had a negative influence on many species, particularly cavity nesters. My results do not support theoretical predictions that forest patch size should positively influence bird species richness. However, composition of bird communities does shift toward edge species from interior species with decreasing patch size. Maintaining large forest patches is thus critical for supporting forest interior species, which tend to be of greater conservation concern. Maintenance of metapopulations requires movement of dispersers among resource patches. The degree to which a landscape facilitates or impedes such movements is defined as functional connectivity. Habitat fragmentation may reduce the functional connectivity of a landscape, but empirical linkages between distribution patterns and movement ability are lacking. In Chapter 4, I use experimental translocations to test whether forest fragmentation impedes movement of two species identified as fragmentation-sensitive in Chapter 3: Wood Thrush (Hylocichla mustelina) and Ovenbirds (Seiurus aurocapilla). I also tested for behavioral changes in translocated birds and evaluated whether fragmentation effects differed between behavioral modes. Over two breeding seasons, we translocated 35 Wood Thrush and 19 Ovenbirds (1-1.2 km) across landscapes spanning a fragmentation gradient and recorded their movement paths using VHF transmitters and receivers. Eighty-seven percent of individuals returned successfully, taking as long as 72.2 hours. Movement patterns of 96% of successful birds indicated two distinct behavioral modes: exploring, characterized by short, undirected movements and course reversals; and homing, characterized by large, fast steps towards their home territories. Forest composition and configuration had no effect on homing time or path straightness for either species. However, at a finer scale, I found that both preferred to take steps that minimized their exposure to non-forested gaps. My results demonstrate that movement limitation could drive or exacerbate fragmentation sensitivity for these birds. Further, while fragmentation effects did not differ between behavioral modes, my results highlight the need to link the dichotomous behaviors of translocated animals with natural movement processes. Despite this knowledge gap, results from our study suggest that maintaining contiguous habitat or corridors may improve functional connectivity for fragmentation-sensitive birds.
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2548. [Article] Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007
Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated ...Citation Citation
- Title:
- Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007
Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated above Clear Branch Dam, which provides limited downstream fish passage during infrequent and sporadic periods of spill and no upstream passage. Bull trout in this population inhabit Laurance Lake Reservoir and tributaries upstream of Clear Branch Dam. The Hood River local population occurs in the mainstem Hood River and Middle Fork Hood River downstream of the Clear Branch Dam and a small number of adult bull trout migrate each year into the Hood River from the Columbia River (Figure 1). The status of both populations is extremely precarious. The Clear Branch population is at risk of a random extinction event due to low numbers, negative interactions with non-native smallmouth bass, isolation and limited spawning habitat (USFWS, 1998). The Hood River population also appears to be small and is threatened by passage barriers, unscreened irrigation systems, impaired water quality and periodic siltation of spawning substrate by glacial outbursts. Clear Branch bull trout spawn in Clear Branch and Pinnacle Creek. After rearing in these two natal streams for an unknown time period, most are believed to migrate downstream to Laurance Lake Reservoir. Clear Branch bull trout have been documented passing over the dam spillway during high water events (Pribyl et al. 1996) and may provide a recruitment source for the Hood River local population. Adult bull trout tagged at Powerdale Dam have been observed at Coe Branch irrigation diversion and in a trap at the base of Clear Branch dam. These fish may have been attempting to reach spawning areas located upstream of the dam. However, the success of bull trout migrating downstream via the spillway or the possibility of successfully navigating through the diversion network has never been determined. Depending on the water year, the Middle Fork Irrigation District (MFID) may not spill at all, or the timing of the spill may not coincide with the timing of downstream migration, which is currently unknown (East Fork Hood River and Middle Fork Hood River Watershed analysis). Smallmouth bass were discovered in Lake Laurance Reservoir in the 1990s. Creel surveys have shown that large adult bass are caught occasionally in the reservoir and schools of bass fry have been seen by district fish biologist (Rod French, ODFW, personal communication), suggesting that they are spawning successfully. This illegal introduction poses a potential threat to the Clear Branch bull trout population, but its magnitude is unknown because the bass population size and degree of interaction between the two species are unknown. Bull trout and smallmouth bass have significantly different temperature preferences and tolerances, with bull trout being one of the most sensitive coldwater species and bass being a warm water species. Lake Laurance, a relatively high-altitude reservoir at 890 m (2,920 feet), does not provide ideal bass habitat so these two species may have largely non-overlapping distributions or differing activity periods (Terry Shrader, ODFW warmwater fish biologist, personal communication). However, based on past reservoir temperature data (Berger et al. 2005), there are periods in the reservoir when there is potential for bull trout and bass interaction: periods when bull trout are susceptible to bass predation and when juvenile fish might compete for resources. Spawning activity of the Hood River local population has been observed in a few locations within the Middle Fork of Hood River (Figure 1). Although consistent and extensive spawning areas for this population are not known, some of the locations where juvenile rearing or potential bull trout redds have been observed include the Middle Fork Hood River and some of its tributaries: Bear Creek, Compass Creek and Coe Branch (USFWS 2004). However, Coe Branch, Compass Creek, and the Middle Fork are glacial streams with a high volume of sand and silt which may compromise spawning success. No bull trout spawning or rearing has been observed on the East and West Forks of Hood River. The Middle Fork and mainstem Hood River provide foraging, migration and overwintering habitat. Hood River bull trout are also known to migrate into the Columbia River. Two bull trout tagged at Powerdale Dam (RK 7.2 of mainstem Hood River) were recovered near Drano Lake in Washington State; and one was captured 11 kilometers downstream of the confluence of the Hood and Columbia Rivers (USFWS 2004). Every year (usually between May and July), adult bull trout, presumably migrating upstream from the Columbia River, are captured and anchor tagged at Powerdale Dam. Although some of these tagged fish have been observed upstream (one in Coe Branch and three below Clear Branch dam), the spawning destination of fluvial adults within the Hood River basin is largely unknown. Dispersing juvenile bull trout and migrating adults in this local population are threatened by flow diversions with inadequate screening and passage facilities. Several structures are suspected to impede upstream migration or entrain juvenile and adult bull trout into irrigation works (Pribyl et al. 1996, HRWG 1999). These structures include: the diversion at Clear Branch Dam (passage and screening), Coe Branch (passage and screening), and the Farmers Irrigation District diversion (screening) on the mainstem Hood River (HRWG 1999). However, little research has been conducted to assess the impacts of these structures on migrating bull trout. Beyond a general knowledge of the distribution of Hood River bull trout and the nature of anthropogenic factors that potentially restrict their life history and habitat connectivity, little is known about this recovery unit. Baseline information about adult abundance is lacking for both local populations, the potential of a source (Clear Branch) and sink (Hood River) relationship between the two local populations has not been explored, and the migratory life history of adult fish caught at Powerdale Dam is unknown. The degree to which irrigation and hydropower diversions hamper connectivity within the Hood River basin is also poorly understood. Migratory life histories have been viewed as key to species persistence (Rieman and McIntyre 1995; Dunham and Rieman 1999), and understanding movement patterns and associated habitat requirements are critical to maintaining those migratory forms (Muhlfeld and Morotz 2005; Hostettler 2005). Gaining this information is also critical to evaluating bull trout recovery in the Hood River Subbasin (Coccoli 2004). The Oregon Department of Fish and Wildlife (ODFW) initiated a study in 2006 to improve our understanding of the abundance, life history, and potential limiting factors of the bull trout in this recovery unit. This report describes findings for the first two years of the study (2006-2007). Specific study objectives for the first two years were: 1. Determine the migratory life history of Hood River bull trout and assess the potential impacts of flow diversions and two new falls on the Middle Fork Hood River (scoured by the November 2006 glacial outburst) on bull trout migrations. 2. Determine current distribution of bull trout reproduction and early rearing in historical and potential bull trout streams in the Hood River Subbasin. 3. Determine the juvenile and adult life history the Clear Branch local population and develop a statistically reliable and cost-effective protocol for monitoring the abundance of adult Clear Branch bull trout. 4. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake Reservoir.