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• 1731. [Article] A sensitivity-based approach to evaluating future changes in Colorado River Discharge

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/10584.

  Citation × Citation Citation Abstract Copy Title: A sensitivity-based approach to evaluating future changes in Colorado River Discharge Author: Vano, Julie A., Lettenmaier, Dennis P. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/10584. Title: A sensitivity-based approach to evaluating future changes in Colorado River Discharge Author: Vano, Julie A., Lettenmaier, Dennis P. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/10584. Close

• 1732. [Article] Multilinear Regression Equations for Predicting Lateral Spread Displacement from Soil Type and CPT Data

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: http://cedb.asce.o...

  Citation × Citation Citation Abstract Copy Title: Multilinear Regression Equations for Predicting Lateral Spread Displacement from Soil Type and CPT Data Author: Bartlett, Steven F., Gillins, Daniel T. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: http://cedb.asce.org. Title: Multilinear Regression Equations for Predicting Lateral Spread Displacement from Soil Type and CPT Data Author: Bartlett, Steven F., Gillins, Daniel T. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: http://cedb.asce.org. Close

• 1733. [Article] 1884-1923 Oregon coast bird notes in biological survey files

  The purpose of this work is to make available reports and letters for the Oregon Coast that were in the files of the Biological Survey and that are now in the files of the Biological Survey's successor, ...

  Citation × Citation Citation Abstract Copy Title: 1884-1923 Oregon coast bird notes in biological survey files Author: Bayer, Range D., 1947- The purpose of this work is to make available reports and letters for the Oregon Coast that were in the files of the Biological Survey and that are now in the files of the Biological Survey's successor, the U.S. Fish and Wildlife Service. I have changed outdated bird names to those that are used today, so that the reader can more easily understand the reports. But this monograph does not analyze these reports or letters; that is left to the reader. Not all of these reports were done for the Biological Survey. The reports in 1884 and 1885 were for the American Ornithologists' Union Committee on Bird Migration, reports in 1886-1890 were for the U.S. Department of Agriculture (USDA), Division of Entomology, Investigations in Economic Ornithology; reports in 1891-1896 were for the USDA, Division of Economic Ornithology and Mammalogy or Division of Ornithology and Mammalogy; reports in 1897-1905 were for the USDA, Division of Biological Survey; and reports in 1906-1923 were for the USDA, Bureau of Biological Survey. Ira N. Gabrielson and Stanley G. Jewett both worked for the Biological Survey and used some of the unpublished information in the Biological Survey files in writing their classic 1940 book. They discussed the work of the Biological Survey in Oregon on their pages 56-58. The observations in the Biological Survey files and those cited by Gabrielson and Jewett (1940) are sometimes the only information available about birds in some parts of Oregon prior to 1940. Unfortunately, it has not been widely known that at least some of the files accumulated by the Biological Survey still exist and are on microfilm ("Bird Migration Schedules, Reel 17, North Dakota, Oklahoma, Oregon, and Ohio") at the U.S. Fish and Wildlife Service's Patuxent Wildlife Research Center Library in Laurel, Maryland. Upon request, the Patuxent Library may loan out the microfilm reel through Interlibrary Loan to an established library, where the reader can then peruse the contents. Title: 1884-1923 Oregon coast bird notes in biological survey files Author: Bayer, Range D., 1947- The purpose of this work is to make available reports and letters for the Oregon Coast that were in the files of the Biological Survey and that are now in the files of the Biological Survey's successor, the U.S. Fish and Wildlife Service. I have changed outdated bird names to those that are used today, so that the reader can more easily understand the reports. But this monograph does not analyze these reports or letters; that is left to the reader. Not all of these reports were done for the Biological Survey. The reports in 1884 and 1885 were for the American Ornithologists' Union Committee on Bird Migration, reports in 1886-1890 were for the U.S. Department of Agriculture (USDA), Division of Entomology, Investigations in Economic Ornithology; reports in 1891-1896 were for the USDA, Division of Economic Ornithology and Mammalogy or Division of Ornithology and Mammalogy; reports in 1897-1905 were for the USDA, Division of Biological Survey; and reports in 1906-1923 were for the USDA, Bureau of Biological Survey. Ira N. Gabrielson and Stanley G. Jewett both worked for the Biological Survey and used some of the unpublished information in the Biological Survey files in writing their classic 1940 book. They discussed the work of the Biological Survey in Oregon on their pages 56-58. The observations in the Biological Survey files and those cited by Gabrielson and Jewett (1940) are sometimes the only information available about birds in some parts of Oregon prior to 1940. Unfortunately, it has not been widely known that at least some of the files accumulated by the Biological Survey still exist and are on microfilm ("Bird Migration Schedules, Reel 17, North Dakota, Oklahoma, Oregon, and Ohio") at the U.S. Fish and Wildlife Service's Patuxent Wildlife Research Center Library in Laurel, Maryland. Upon request, the Patuxent Library may loan out the microfilm reel through Interlibrary Loan to an established library, where the reader can then peruse the contents. Close

• 1734. [Article] Observations and assessment of forest carbon dynamics following disturbance in North America

  This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/jgr/. To the best of our knowledge, one or more ...

  Citation × Citation Citation Abstract Copy Title: Observations and assessment of forest carbon dynamics following disturbance in North America Author: Pfeifer, E. M., Kasischke, E. S., Houghton, R. A., McNulty, S., Law, B. E., Goetz, S. J., Harmon, M., Huang, C., Meddens, A. J. H., Mildrexler, D., Bond-Lamberty, B., O'Halloran, T., Hicke, J. A. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/jgr/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Observations and assessment of forest carbon dynamics following disturbance in North America Author: Pfeifer, E. M., Kasischke, E. S., Houghton, R. A., McNulty, S., Law, B. E., Goetz, S. J., Harmon, M., Huang, C., Meddens, A. J. H., Mildrexler, D., Bond-Lamberty, B., O'Halloran, T., Hicke, J. A. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/jgr/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 1735. [Article] Colony Connectivity of Pacific Coast Double-Crested Cormorants Based on Post-Breeding Dispersal From the Region’s Largest Colony

  This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Inc. and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291937-2817. To the best of ...

  Citation × Citation Citation Abstract Copy Title: Colony Connectivity of Pacific Coast Double-Crested Cormorants Based on Post-Breeding Dispersal From the Region’s Largest Colony Author: Roby, Daniel D., Lyons, Donald E., Adkins, Jessica Y., Courtot, Karen N., Larsen, R. Scott, King, D. Tommy This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Inc. and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291937-2817. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Colony Connectivity of Pacific Coast Double-Crested Cormorants Based on Post-Breeding Dispersal From the Region’s Largest Colony Author: Roby, Daniel D., Lyons, Donald E., Adkins, Jessica Y., Courtot, Karen N., Larsen, R. Scott, King, D. Tommy This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Inc. and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291937-2817. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 1736. [Article] Demand analysis for surimi-based products in Japan

  Since the "200 miles" fishery conservation zones were established by some coastal countries, new arrangements between countries to participate jointly in fishing, processing, and marketing of fish products have ...

  Citation × Citation Citation Abstract Copy Title: Demand analysis for surimi-based products in Japan Author: Kim, Seung-woo Since the "200 miles" fishery conservation zones were established by some coastal countries, new arrangements between countries to participate jointly in fishing, processing, and marketing of fish products have emerged. One such fish product is surimi. As a result of extended jurisdiction, each coastal country's interest in the surimi industry is increasing and many efforts for market research and development of surimi technology are being taken in these countries. To understand this market it is important to know the nature of the demand for surimi-based products. However, there are not enough data available for demand analysis of surimi-based products due to the short history of the surimi industry on a global basis and the uncertain supply situation. Therefore, the Japanese market for surimi-based products, which has a long history and is the world's largest market for surimi, was chosen to improve understanding of the global market for surimi-based products. The approach adopted to meet this goal is the demand system approach, which allows the analysis to model the interdependencies among prices and consumption in consumer demand. Careful specification of demand relationships in the Japanese market for surimi-based products permits the testing of hypotheses about the impact of changes in availability of other seafoods and red meats on the demand for surimi-based products in Japan. Two different demand system models, the almost ideal demand system (AIDS) model and the habit formation (HF) model, are used for this demand analysis. Especially in the AIDS model, the homogeneity and symmetry restrictions are tested and the simultaneous impacts on consumption of surimi-based products, red meats, and other seafood of changes on the prices of these commodities are examined. The habit formation model is used mainly to investigate habit persistence in the Japanese market. The results of estimating the AIDS model show that the expenditure elasticities of surimi-based products are greater than unity and that the demands for surimi-based products are generally price-inelastic, while the own price elasticity of kamaboko is greater than unity. Also, these results show that surimi-based products are more likely to have complementary relationships with other fish products. However, the nature of substitutional relationships with red meats could not be determined by this analysis. The estimation results of the habit formation model show that habit persistence of consumers exists in Japan's fish and meat market, including surimi-based products. Title: Demand analysis for surimi-based products in Japan Author: Kim, Seung-woo Since the "200 miles" fishery conservation zones were established by some coastal countries, new arrangements between countries to participate jointly in fishing, processing, and marketing of fish products have emerged. One such fish product is surimi. As a result of extended jurisdiction, each coastal country's interest in the surimi industry is increasing and many efforts for market research and development of surimi technology are being taken in these countries. To understand this market it is important to know the nature of the demand for surimi-based products. However, there are not enough data available for demand analysis of surimi-based products due to the short history of the surimi industry on a global basis and the uncertain supply situation. Therefore, the Japanese market for surimi-based products, which has a long history and is the world's largest market for surimi, was chosen to improve understanding of the global market for surimi-based products. The approach adopted to meet this goal is the demand system approach, which allows the analysis to model the interdependencies among prices and consumption in consumer demand. Careful specification of demand relationships in the Japanese market for surimi-based products permits the testing of hypotheses about the impact of changes in availability of other seafoods and red meats on the demand for surimi-based products in Japan. Two different demand system models, the almost ideal demand system (AIDS) model and the habit formation (HF) model, are used for this demand analysis. Especially in the AIDS model, the homogeneity and symmetry restrictions are tested and the simultaneous impacts on consumption of surimi-based products, red meats, and other seafood of changes on the prices of these commodities are examined. The habit formation model is used mainly to investigate habit persistence in the Japanese market. The results of estimating the AIDS model show that the expenditure elasticities of surimi-based products are greater than unity and that the demands for surimi-based products are generally price-inelastic, while the own price elasticity of kamaboko is greater than unity. Also, these results show that surimi-based products are more likely to have complementary relationships with other fish products. However, the nature of substitutional relationships with red meats could not be determined by this analysis. The estimation results of the habit formation model show that habit persistence of consumers exists in Japan's fish and meat market, including surimi-based products. Close

• 1737. [Article] Sediment transport in a gravel-bottomed stream

  Sediment transport in a gravel-bottomed stream located in the Oregon Coast Range was studied to determine the effects of a single layer of large particles (the armour layer) located at the surface of the ...

  Citation × Citation Citation Abstract Copy Title: Sediment transport in a gravel-bottomed stream Author: Milhous, Robert T. Sediment transport in a gravel-bottomed stream located in the Oregon Coast Range was studied to determine the effects of a single layer of large particles (the armour layer) located at the surface of the bed material. The bed load transport system was studied jointly with suspended sediment transport to understand the total transport system. The bed load was sampled using a vortex trough in the stream bed which transported the bed load material into a sampling pit adjacent to the stream. It was found that the armour layer controls the bed load transport system by preventing sand and finer material from the bed from being entrained in the flow unless the armouring particles are first moved. The bed load of an armoured stream can be calculated using the simplified Einstein bed load function with a representative diameter for the stability parameter equal to the particle size of armouring material at which 35% of the material is finer (D35 size) and a representative size for the transport parameter equal to the median site of bed material below the armour layer. The critical discharge for disturbing the armour layer is related to a size equal to 69% of the D65 size. The critical shear stress of the armouring material is at a minimum for a particle equal to the 0.69 D65 size. Smaller particles are hidden in the armour layer and larger particles are heavier than the critical particle. From observation of the maximum size of particles transported for various stream discharges, the Shields parameter was found to be 0.025 for a rough bed and for a transport rate of very nearly zero. The suspended sediment transport system was found to be partially related to the past history of the stream because the past history f flows and sediment load controls the ability of the armour layer to remove sand and finer material from the water in the stream or to supply these smaller particles to the water. Both the bed load and suspended load of Oak Creek are quite variable when the discharge is below the critical discharge of the armour layer. Title: Sediment transport in a gravel-bottomed stream Author: Milhous, Robert T. Sediment transport in a gravel-bottomed stream located in the Oregon Coast Range was studied to determine the effects of a single layer of large particles (the armour layer) located at the surface of the bed material. The bed load transport system was studied jointly with suspended sediment transport to understand the total transport system. The bed load was sampled using a vortex trough in the stream bed which transported the bed load material into a sampling pit adjacent to the stream. It was found that the armour layer controls the bed load transport system by preventing sand and finer material from the bed from being entrained in the flow unless the armouring particles are first moved. The bed load of an armoured stream can be calculated using the simplified Einstein bed load function with a representative diameter for the stability parameter equal to the particle size of armouring material at which 35% of the material is finer (D35 size) and a representative size for the transport parameter equal to the median site of bed material below the armour layer. The critical discharge for disturbing the armour layer is related to a size equal to 69% of the D65 size. The critical shear stress of the armouring material is at a minimum for a particle equal to the 0.69 D65 size. Smaller particles are hidden in the armour layer and larger particles are heavier than the critical particle. From observation of the maximum size of particles transported for various stream discharges, the Shields parameter was found to be 0.025 for a rough bed and for a transport rate of very nearly zero. The suspended sediment transport system was found to be partially related to the past history of the stream because the past history f flows and sediment load controls the ability of the armour layer to remove sand and finer material from the water in the stream or to supply these smaller particles to the water. Both the bed load and suspended load of Oak Creek are quite variable when the discharge is below the critical discharge of the armour layer. Close

• 1738. [Article] Fibrinogen adsorption at heparinized silica interfaces : history dependence and protein concentration effects

  Adipic dihydrazide-modified heparin was prepared and subsequently immobilized on surface-activated silica wafers. X-ray photoelectron spectroscopy (XPS) was used to quantify the elemental composition of ...

  Citation × Citation Citation Abstract Copy Title: Fibrinogen adsorption at heparinized silica interfaces : history dependence and protein concentration effects Author: Joshi, Omkar Adipic dihydrazide-modified heparin was prepared and subsequently immobilized on surface-activated silica wafers. X-ray photoelectron spectroscopy (XPS) was used to quantify the elemental composition of the silica surface at each stage of activation and results showed that successful immobilization had taken place. Contact angle measurements were made to verify the high hydrophilicity of the heparinized and unheparinized silica surfaces. In situ ellipsometry was used to study protein concentration effects on adsorption kinetics exhibited by human plasma fibrinogen on unheparinized and heparinized silica. The adsorbed amount of fibrinogen increased with concentration, on each type of surface. At all concentrations, fibrinogen adsorbed in diminished amounts and at a slower rate on heparinized as compared to unheparinized silica. Buffer elution experiments showed that fibrinogen was less tightly bound on heparinized silica. To examine the history dependence of adsorption, fibrinogen was added for a second time, after rinsing. The difference in adsorption rates between the first and second adsorption cycle evaluated at identical mass density, indicated that post-adsorptive molecular rearrangements had taken place. These rearrangements presumably involved aggregation of adsorbed fibrinogen, in this way increasing unoccupied area at the interface. Fibrinogen was postulated to be more mobile on heparinized silica. Title: Fibrinogen adsorption at heparinized silica interfaces : history dependence and protein concentration effects Author: Joshi, Omkar Adipic dihydrazide-modified heparin was prepared and subsequently immobilized on surface-activated silica wafers. X-ray photoelectron spectroscopy (XPS) was used to quantify the elemental composition of the silica surface at each stage of activation and results showed that successful immobilization had taken place. Contact angle measurements were made to verify the high hydrophilicity of the heparinized and unheparinized silica surfaces. In situ ellipsometry was used to study protein concentration effects on adsorption kinetics exhibited by human plasma fibrinogen on unheparinized and heparinized silica. The adsorbed amount of fibrinogen increased with concentration, on each type of surface. At all concentrations, fibrinogen adsorbed in diminished amounts and at a slower rate on heparinized as compared to unheparinized silica. Buffer elution experiments showed that fibrinogen was less tightly bound on heparinized silica. To examine the history dependence of adsorption, fibrinogen was added for a second time, after rinsing. The difference in adsorption rates between the first and second adsorption cycle evaluated at identical mass density, indicated that post-adsorptive molecular rearrangements had taken place. These rearrangements presumably involved aggregation of adsorbed fibrinogen, in this way increasing unoccupied area at the interface. Fibrinogen was postulated to be more mobile on heparinized silica. Close

• 1739. [Article] Expression & identity : the word made flesh

  This essay is an exploration of identity formation and expression. Humanity's identity formations create the orientations and languages with which we use to create our knowledge and understanding of the ...

  Citation × Citation Citation Abstract Copy Title: Expression & identity : the word made flesh Author: Beach, J. M. This essay is an exploration of identity formation and expression. Humanity's identity formations create the orientations and languages with which we use to create our knowledge and understanding of the surrounding external environment (both social and physical) and our internal environment (psychological). This essay traces the sources of identity formation to the mythological creation of ancient poets and seeks to develop an understanding of the ideas behind mythological thinking and expression. 'Poetry' is a term derived from the ancient Greek word for 'maker,' 'shaper,' and 'former;' serving in this essay as a guide through history's mythological structures of identity formation in the various historical manifestations of art, philosophy, religion, and psychology. Identity's value lies in its personal and communal modes of expression used to form practical definitions for the development of knowledge and understanding of the internal world of our being and the external world outside and/or related to our being. Identity also holds an inherent danger as our identity formations, once becoming objective realities, can begin to dominate and repress other identities or our ability to create alternate identities. The later scenario is represented in current cultural, psychological, and epistemological theories based upon 'domination' while a counter trend could be seen in 'relational' systems based upon reciprocity: hostile dualisms which privilege one side over another or a more harmonious system of balance and mutual definition. It is the author's claim that the later, more harmonious system is the core 'value' found within poetic thought and he tries to present an outline to a 'philosophy of poetry,' which would further develop this idea. Poetry is not only an external manifestation, but also a state of being, and tenets for the understanding of poetic sensibility are outlined and unified under a terminology of 'Vision' and 'Unity.' Mythological thinking and expression are held to be the roots of the various social manifestations of the terms 'Vision' and 'Unity' found within poetic philosophies recorded throughout human history. This essay is the framework for a larger work in progress by the author, and should be read and understood as such. Title: Expression & identity : the word made flesh Author: Beach, J. M. This essay is an exploration of identity formation and expression. Humanity's identity formations create the orientations and languages with which we use to create our knowledge and understanding of the surrounding external environment (both social and physical) and our internal environment (psychological). This essay traces the sources of identity formation to the mythological creation of ancient poets and seeks to develop an understanding of the ideas behind mythological thinking and expression. 'Poetry' is a term derived from the ancient Greek word for 'maker,' 'shaper,' and 'former;' serving in this essay as a guide through history's mythological structures of identity formation in the various historical manifestations of art, philosophy, religion, and psychology. Identity's value lies in its personal and communal modes of expression used to form practical definitions for the development of knowledge and understanding of the internal world of our being and the external world outside and/or related to our being. Identity also holds an inherent danger as our identity formations, once becoming objective realities, can begin to dominate and repress other identities or our ability to create alternate identities. The later scenario is represented in current cultural, psychological, and epistemological theories based upon 'domination' while a counter trend could be seen in 'relational' systems based upon reciprocity: hostile dualisms which privilege one side over another or a more harmonious system of balance and mutual definition. It is the author's claim that the later, more harmonious system is the core 'value' found within poetic thought and he tries to present an outline to a 'philosophy of poetry,' which would further develop this idea. Poetry is not only an external manifestation, but also a state of being, and tenets for the understanding of poetic sensibility are outlined and unified under a terminology of 'Vision' and 'Unity.' Mythological thinking and expression are held to be the roots of the various social manifestations of the terms 'Vision' and 'Unity' found within poetic philosophies recorded throughout human history. This essay is the framework for a larger work in progress by the author, and should be read and understood as such. Close

• 1740. [Article] Models of a four-species annual weed community : growth, competition, and community dynamics

  Models of weed communities aid in the development of weed management strategies and elucidate the processes and mechanisms that regulate plant populations and communities. A conceptual weed community model ...

  Citation × Citation Citation Abstract Copy Title: Models of a four-species annual weed community : growth, competition, and community dynamics Author: Roush, Mary Lynn Models of weed communities aid in the development of weed management strategies and elucidate the processes and mechanisms that regulate plant populations and communities. A conceptual weed community model was developed to organize key regulatory life-history processes. Specific investigations focused on the processes of plant growth and competition, and relationships between growth ability and competitive ability. Plant competition was investigated from two perspectives: the intensity of competition and the importance of competition. Intensity is the response of a plant to competition; importance is the role of competition in regulating populations and communities. Recent applications of fundamental yield-density relationships have enhanced interpretations that can be made about the mechanisms and implications of competition. Plant growth and competition experiments were conducted for a community of four annual weed species to 1) quantify competition intensity using yield-density relationships, 2) link processes of plant growth and competition, and 3) characterize the importance of competition in the community. The weed species were Amaranthus retroflexus L., Chenmodium album L., Echinochloa crus-galli L., and Lolium multiflorum Lam.. Experiments were conducted for two years in the field, using isolated, container-grown individuals for growth analysis, and an addition series design for competition. Results indicated strong relationships between plant growth traits and competitive abilities; however, these relationships were sensitive to variation in the environment. Yield-density models and population models suggested that the role of competition in population dynamics varied for the four species, and indicated that other key life-history processes may significantly influence the weed community. In particular, seed bank dynamics and interactions between the environment (temperature and light) and growth, competition and seed bank processes were emphasized for further development and implementation of the weed community model. Title: Models of a four-species annual weed community : growth, competition, and community dynamics Author: Roush, Mary Lynn Models of weed communities aid in the development of weed management strategies and elucidate the processes and mechanisms that regulate plant populations and communities. A conceptual weed community model was developed to organize key regulatory life-history processes. Specific investigations focused on the processes of plant growth and competition, and relationships between growth ability and competitive ability. Plant competition was investigated from two perspectives: the intensity of competition and the importance of competition. Intensity is the response of a plant to competition; importance is the role of competition in regulating populations and communities. Recent applications of fundamental yield-density relationships have enhanced interpretations that can be made about the mechanisms and implications of competition. Plant growth and competition experiments were conducted for a community of four annual weed species to 1) quantify competition intensity using yield-density relationships, 2) link processes of plant growth and competition, and 3) characterize the importance of competition in the community. The weed species were Amaranthus retroflexus L., Chenmodium album L., Echinochloa crus-galli L., and Lolium multiflorum Lam.. Experiments were conducted for two years in the field, using isolated, container-grown individuals for growth analysis, and an addition series design for competition. Results indicated strong relationships between plant growth traits and competitive abilities; however, these relationships were sensitive to variation in the environment. Yield-density models and population models suggested that the role of competition in population dynamics varied for the four species, and indicated that other key life-history processes may significantly influence the weed community. In particular, seed bank dynamics and interactions between the environment (temperature and light) and growth, competition and seed bank processes were emphasized for further development and implementation of the weed community model. Close