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• 1551. [Article] Assessing disease impacts of hatcheries on downstream salmonids in the Willamette River Basin, Oregon

  Hatcheries are often perceived as a source of pathogen amplification, potentially increasing disease risk to free-ranging populations; at the same time, free-ranging fishes may introduce pathogens into ...

  Citation × Citation Citation Abstract Copy Title: Assessing disease impacts of hatcheries on downstream salmonids in the Willamette River Basin, Oregon Author: Jakaitis, Michelle Hatcheries are often perceived as a source of pathogen amplification, potentially increasing disease risk to free-ranging populations; at the same time, free-ranging fishes may introduce pathogens into hatcheries through untreated water sources. Many pathogens exist naturally within the environment (with the exception of introduced pathogens) and the presence of a pathogen does not guarantee infection or disease (Naish, Taylor III, Levin, Quinn, Winton, Huppert & Hilborn 2007). Infections can be acute, chronic, or asymptomatic, fish may die, recover, or become carriers (Naish et al. 2007), and pathogens may be shed from any of these stages (Scottish Executive 2002). Most salmon and trout hatcheries along the Willamette River Basin, Oregon, USA, utilize an untreated river water supply for their rearing ponds and release this water, untreated, back into the river. This creates a potential for waterborne pathogens present in free-ranging hosts to be transmitted through the water supply to hatchery populations. Moreover, any hatchery epizootic can amplify pathogens and release these into the water, which could have a direct impact on free-ranging populations exposed to those pathogens in hatchery effluent. The goal of this thesis was to assess transmission of the pathogens Flavobacterium columnare, F. psychrophilum, Aeromonas salmonicida, Renibacterium salmonicida, and Infectious Hematopoietic Necrosis Virus (IHNV), at selected hatcheries in the Willamette River Basin. To accomplish this, I considered historical data and hatchery-specific and pathogen-specific factors involved in transmission and disease. Additionally, I conducted sentinel fishes exposures (Oncorhynchus mykiss and O. tshawytscha) at hatcheries during both epizootics and non-epizootic periods. Naïve sentinel fish were placed in hatchery influents and effluents to determine transmission direction and pathogen prevalence associated with hatcheries. I found that sentinel fishes developed infections downstream of hatcheries that were undergoing specific bacterial epizootics, or had low levels of pathogen prevalence within the hatchery, but not at any other time. Infections and mortality were due to the same pathogens responsible for hatchery epizootics, indicating the hatchery as a potential source. This may be a limited effect dependent on distance, dilution, and pathogen. The presence of large numbers of returning, congregating adult fishes may also contribute pathogens to the river in hatchery areas. Sentinel fishes held in hatchery influents did not, at any point, become infected with target pathogens, even during hatchery epizootics. Although I was unable to identify the pathogen entry point leading to hatchery epizootics, I determined that pathogen transmission appeared to be dependent on the pathogen, species, and location where sentinel fish were held. This thesis identifies routes and risks of pathogen transmission at selected Oregon hatcheries, with applications to inform state-wide fish health management. Title: Assessing disease impacts of hatcheries on downstream salmonids in the Willamette River Basin, Oregon Author: Jakaitis, Michelle Hatcheries are often perceived as a source of pathogen amplification, potentially increasing disease risk to free-ranging populations; at the same time, free-ranging fishes may introduce pathogens into hatcheries through untreated water sources. Many pathogens exist naturally within the environment (with the exception of introduced pathogens) and the presence of a pathogen does not guarantee infection or disease (Naish, Taylor III, Levin, Quinn, Winton, Huppert & Hilborn 2007). Infections can be acute, chronic, or asymptomatic, fish may die, recover, or become carriers (Naish et al. 2007), and pathogens may be shed from any of these stages (Scottish Executive 2002). Most salmon and trout hatcheries along the Willamette River Basin, Oregon, USA, utilize an untreated river water supply for their rearing ponds and release this water, untreated, back into the river. This creates a potential for waterborne pathogens present in free-ranging hosts to be transmitted through the water supply to hatchery populations. Moreover, any hatchery epizootic can amplify pathogens and release these into the water, which could have a direct impact on free-ranging populations exposed to those pathogens in hatchery effluent. The goal of this thesis was to assess transmission of the pathogens Flavobacterium columnare, F. psychrophilum, Aeromonas salmonicida, Renibacterium salmonicida, and Infectious Hematopoietic Necrosis Virus (IHNV), at selected hatcheries in the Willamette River Basin. To accomplish this, I considered historical data and hatchery-specific and pathogen-specific factors involved in transmission and disease. Additionally, I conducted sentinel fishes exposures (Oncorhynchus mykiss and O. tshawytscha) at hatcheries during both epizootics and non-epizootic periods. Naïve sentinel fish were placed in hatchery influents and effluents to determine transmission direction and pathogen prevalence associated with hatcheries. I found that sentinel fishes developed infections downstream of hatcheries that were undergoing specific bacterial epizootics, or had low levels of pathogen prevalence within the hatchery, but not at any other time. Infections and mortality were due to the same pathogens responsible for hatchery epizootics, indicating the hatchery as a potential source. This may be a limited effect dependent on distance, dilution, and pathogen. The presence of large numbers of returning, congregating adult fishes may also contribute pathogens to the river in hatchery areas. Sentinel fishes held in hatchery influents did not, at any point, become infected with target pathogens, even during hatchery epizootics. Although I was unable to identify the pathogen entry point leading to hatchery epizootics, I determined that pathogen transmission appeared to be dependent on the pathogen, species, and location where sentinel fish were held. This thesis identifies routes and risks of pathogen transmission at selected Oregon hatcheries, with applications to inform state-wide fish health management. Close

• 1552. [Article] Development of an enzyme-linked immunosorbent assay to detect antibodies against Pasteurella multocida in infected rabbits

  Enzyme-linked immunosorbent assays (ELISA) were developed to detect rabbit antibodies against Pasteurella multocida. Antigens for ELISA were prepared from 2.5% saline extracts of P. multocida by chromatographic ...

  Citation × Citation Citation Abstract Copy Title: Development of an enzyme-linked immunosorbent assay to detect antibodies against Pasteurella multocida in infected rabbits Author: Hwang, Eun Ju Enzyme-linked immunosorbent assays (ELISA) were developed to detect rabbit antibodies against Pasteurella multocida. Antigens for ELISA were prepared from 2.5% saline extracts of P. multocida by chromatographic methods. From a crude saline extract of a type 3, 4 isolate designated as R11146, two protein peaks were obtained by gel filtration with Sephadex G-200. The first peak produced a single precipitin line with rabbit anti-whole cell or anti-purified type 3 antigen sera. The first peak was further purified by DEAE-cellulose chromatography. Four protein peaks were obtained, and all of them contained a single identical antigen. The purified antigen contained two protein species of molecular weights of 44,000 and 25,500. The purified antigen was attached to 96 well microtiter plates, and an ELISA was developed by the use of alka-line phosphatase-conjugated sheep anti-rabbit IgG to detect anti bodies. Six Pasteurella-free rabbits were intranasally infected with R11146 isolate and antibody responses were measured by the ELISA. High titers ranging from 1:10³ to 1:10⁴ persisted for longer than 96 days after the infection, while the titers of all the preinoculation sera were lower than 1:10. A similar surface antigen was also purified from a type 12 isolate, R040. Three protein peaks were obtained from crude extract by gel filtration with Sephadex G-200. The first peak contained a major antigen. In some instances, crude extract was concentrated by ultracentrifugation prior to the gel filtration. A major protein component of molecular weights 42,000 and minor ones of 25,000 and 110,000 were present in t the first peak fraction. The antigen purified from a type 12 isolate showed antigenic cross-reaction with the purified antigen from a type 3, 4 isolate. An ELISA was developed with the purified type 12 antigen, and used for detecting antibodies in rabbits intranasally infected with the type 12 strain. Titers of ELISA ranging from 1:10⁴ to 1:10⁵ were obtained for longer than 77 days post inoculation. The preinoculation sera showed titers of less than 1:50. The results indicate that the purified antigen is useful to detect antibodies against P. multocida in rabbits infected with type 3 or type 12 strains. Title: Development of an enzyme-linked immunosorbent assay to detect antibodies against Pasteurella multocida in infected rabbits Author: Hwang, Eun Ju Enzyme-linked immunosorbent assays (ELISA) were developed to detect rabbit antibodies against Pasteurella multocida. Antigens for ELISA were prepared from 2.5% saline extracts of P. multocida by chromatographic methods. From a crude saline extract of a type 3, 4 isolate designated as R11146, two protein peaks were obtained by gel filtration with Sephadex G-200. The first peak produced a single precipitin line with rabbit anti-whole cell or anti-purified type 3 antigen sera. The first peak was further purified by DEAE-cellulose chromatography. Four protein peaks were obtained, and all of them contained a single identical antigen. The purified antigen contained two protein species of molecular weights of 44,000 and 25,500. The purified antigen was attached to 96 well microtiter plates, and an ELISA was developed by the use of alka-line phosphatase-conjugated sheep anti-rabbit IgG to detect anti bodies. Six Pasteurella-free rabbits were intranasally infected with R11146 isolate and antibody responses were measured by the ELISA. High titers ranging from 1:10³ to 1:10⁴ persisted for longer than 96 days after the infection, while the titers of all the preinoculation sera were lower than 1:10. A similar surface antigen was also purified from a type 12 isolate, R040. Three protein peaks were obtained from crude extract by gel filtration with Sephadex G-200. The first peak contained a major antigen. In some instances, crude extract was concentrated by ultracentrifugation prior to the gel filtration. A major protein component of molecular weights 42,000 and minor ones of 25,000 and 110,000 were present in t the first peak fraction. The antigen purified from a type 12 isolate showed antigenic cross-reaction with the purified antigen from a type 3, 4 isolate. An ELISA was developed with the purified type 12 antigen, and used for detecting antibodies in rabbits intranasally infected with the type 12 strain. Titers of ELISA ranging from 1:10⁴ to 1:10⁵ were obtained for longer than 77 days post inoculation. The preinoculation sera showed titers of less than 1:50. The results indicate that the purified antigen is useful to detect antibodies against P. multocida in rabbits infected with type 3 or type 12 strains. Close

• 1553. [Article] A comparison of the hydraulic efficiency of a palm species (Iriartea deltoidea) with other wood types

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Oxford University Press and can be found at: http://treephys.oxfordjournals.org...

  Citation × Citation Citation Abstract Copy Title: A comparison of the hydraulic efficiency of a palm species (Iriartea deltoidea) with other wood types Author: Renninger, Heidi J., Phillips, Nathan, McCulloh, Katherine A. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Oxford University Press and can be found at: http://treephys.oxfordjournals.org/. Title: A comparison of the hydraulic efficiency of a palm species (Iriartea deltoidea) with other wood types Author: Renninger, Heidi J., Phillips, Nathan, McCulloh, Katherine A. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Oxford University Press and can be found at: http://treephys.oxfordjournals.org/. Close

• 1554. [Article] Ecological relationships between cervid herbivory and understory vegetation in old-growth Sitka spruce-western hemlock forests in western Washington

  The relationships between black-tailed deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus elaphus roosevelti) herbivory and understory vegetation in unmanaged forests in Olympic National ...

  Citation × Citation Citation Abstract Copy Title: Ecological relationships between cervid herbivory and understory vegetation in old-growth Sitka spruce-western hemlock forests in western Washington Author: Happe, Patricia Jenkins The relationships between black-tailed deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus elaphus roosevelti) herbivory and understory vegetation in unmanaged forests in Olympic National Park were studied from 1985 - 1989. From 1985 to 1986 I studied the impact of cervid exclusion on shrub, fern, and forb forage quality, tannin content, tannin astringency, shrub morphology, and shrub standing crop biomass, in old-growth and seral forests. Long-term protection from cervid herbivory had little effect on forage quality, tannin content, or tannin astringency. However, herbivory reduced leaf area, leaf weight, and plant standing crop biomass. From March 1987 through March 1989 I measured the amount of cervid herbivory in the understory of old-growth forests, and the effects of that herbivory on herb, fern, and shrub biomass, production, and nutrient content. The amount, timing, and impacts of cervid herbivory varied among understory plant communities, plant species, and years. Forage biomass, production, herbivory, and the influence of herbivory, were greatest in areas with grass-dominated understories. In those sites, production was either stimulated or not affected by herbivory, and herbivory altered plant structure and nutrient content such that foraging efficiency was improved during both summer and late winter. In sites with a forb-moss herb layer, biomass, production, and herbivory were less. Although herbivory either stimulated or had no effect on production in forb sites, it had no effect on forage nutrient content or structure, and thus did not impact foraging efficiency. The effects of long-term exclusion of ungulates in the study area indicated that soon after exclusion, grass-dominated understories disappear. Thus, cervid herbivory was found to influence understories in old-growth forest on several spacial and temporal scales. In the short-term, cervid herbivory improved forage structure and nutrient concentration in grass dominated understories. In the long term, cervid herbivory maintained grass dominated patches within the system. On both temporal and spatial scales, the net result of cervid herbivory was the creation of a more favorable foraging environment for both deer and elk. Title: Ecological relationships between cervid herbivory and understory vegetation in old-growth Sitka spruce-western hemlock forests in western Washington Author: Happe, Patricia Jenkins The relationships between black-tailed deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus elaphus roosevelti) herbivory and understory vegetation in unmanaged forests in Olympic National Park were studied from 1985 - 1989. From 1985 to 1986 I studied the impact of cervid exclusion on shrub, fern, and forb forage quality, tannin content, tannin astringency, shrub morphology, and shrub standing crop biomass, in old-growth and seral forests. Long-term protection from cervid herbivory had little effect on forage quality, tannin content, or tannin astringency. However, herbivory reduced leaf area, leaf weight, and plant standing crop biomass. From March 1987 through March 1989 I measured the amount of cervid herbivory in the understory of old-growth forests, and the effects of that herbivory on herb, fern, and shrub biomass, production, and nutrient content. The amount, timing, and impacts of cervid herbivory varied among understory plant communities, plant species, and years. Forage biomass, production, herbivory, and the influence of herbivory, were greatest in areas with grass-dominated understories. In those sites, production was either stimulated or not affected by herbivory, and herbivory altered plant structure and nutrient content such that foraging efficiency was improved during both summer and late winter. In sites with a forb-moss herb layer, biomass, production, and herbivory were less. Although herbivory either stimulated or had no effect on production in forb sites, it had no effect on forage nutrient content or structure, and thus did not impact foraging efficiency. The effects of long-term exclusion of ungulates in the study area indicated that soon after exclusion, grass-dominated understories disappear. Thus, cervid herbivory was found to influence understories in old-growth forest on several spacial and temporal scales. In the short-term, cervid herbivory improved forage structure and nutrient concentration in grass dominated understories. In the long term, cervid herbivory maintained grass dominated patches within the system. On both temporal and spatial scales, the net result of cervid herbivory was the creation of a more favorable foraging environment for both deer and elk. Close

• 1555. [Article] The effects of habitat, climate, and Barred Owls on long-term demography of Northern Spotted Owls

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The article is copyrighted by Cooper Ornithological ...

  Citation × Citation Citation Abstract Copy Title: The effects of habitat, climate, and Barred Owls on long-term demography of Northern Spotted Owls Author: Franklin, Alan B., Diller, Lowell V., Horn, Rob B., Schwarz, Carl J., McCafferty, Christopher, Gremel, Scott A., Biswell, Brian L., Clark, Darren A., Herter, Dale R., Doherty, Paul F. Jr, Hines, James E., McDonnell, Kevin, Bailey, Larissa, Higley, J. Mark, Yackulic, Charles B., Hobson, Jeremy, Burnham, Kenneth P., Dugger, Katie M., Carlson, Peter C., Clement, Matthew J., Davis, Raymond J., Rockweit, Jeremy, Huyvaert, Kathryn P., Andrews, Lawrence S., Forsman, Eric D., Augustine, Benjamin, Saenz, Jessica, Glenn, Elizabeth M., Blakesley, Jennifer, Olson, Gail S., Ackers, Steven H., McDonald, Trent, Nichols, James D., Green, Adam, Ruiz, Viviana, Sovern, Stan G., White, Gary C., Reid, Janice A. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The article is copyrighted by Cooper Ornithological Society and published by Central Ornithology Publication Office. It can be found at: http://www.aoucospubs.org/loi/cond Title: The effects of habitat, climate, and Barred Owls on long-term demography of Northern Spotted Owls Author: Franklin, Alan B., Diller, Lowell V., Horn, Rob B., Schwarz, Carl J., McCafferty, Christopher, Gremel, Scott A., Biswell, Brian L., Clark, Darren A., Herter, Dale R., Doherty, Paul F. Jr, Hines, James E., McDonnell, Kevin, Bailey, Larissa, Higley, J. Mark, Yackulic, Charles B., Hobson, Jeremy, Burnham, Kenneth P., Dugger, Katie M., Carlson, Peter C., Clement, Matthew J., Davis, Raymond J., Rockweit, Jeremy, Huyvaert, Kathryn P., Andrews, Lawrence S., Forsman, Eric D., Augustine, Benjamin, Saenz, Jessica, Glenn, Elizabeth M., Blakesley, Jennifer, Olson, Gail S., Ackers, Steven H., McDonald, Trent, Nichols, James D., Green, Adam, Ruiz, Viviana, Sovern, Stan G., White, Gary C., Reid, Janice A. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The article is copyrighted by Cooper Ornithological Society and published by Central Ornithology Publication Office. It can be found at: http://www.aoucospubs.org/loi/cond Close

• 1556. [Article] Evaluating tools used to estimate and manage browse available to wintering moose on the Copper River Delta, Alaska

  Ungulates comprise some of the most well researched and intensely managed wildlife populations on earth. As such, they are recognized as ideal study subjects for developing and modifying management tools ...

  Citation × Citation Citation Abstract Copy Title: Evaluating tools used to estimate and manage browse available to wintering moose on the Copper River Delta, Alaska Author: Smythe, Sharon E. Ungulates comprise some of the most well researched and intensely managed wildlife populations on earth. As such, they are recognized as ideal study subjects for developing and modifying management tools or theories (Danell et al. 1994, Shipley 2010). An introduced moose (Alces alces gigas) population on the Copper River Delta (CRD; Delta) of south-central Alaska functions as a valuable resource for the residents of Cordova and an isolated research population on which to test managerial techniques. Since its introduction (1949-1958), the founding population of 23 moose has grown to over 830 in 2013, divided into two sub-populations. However, in 1964, the largest earthquake recorded in U.S. history (9.2 magnitude) uplifted the Delta by 1.0-4.0 m, initiating delta-wide changes in hydrology, vegetation distributions, and successional processes. The proportion of stands dominated by woody species, especially alder (Alnus viridis sinuata) and spruce (Picea sitchensis), increased visibly. Furthermore, previous research (1987-89) observed that 90% of the moose on the western region of the Delta wintered within 9-24% of the total land area, possibly restricting their available winter browse. Because moose diets on the CRD are dominated by willows (Salix spp.), managers were concerned that the combined effects of a restricted winter range and earthquake-initiated vegetation changes would negatively influence the population. Managers have responded to this concern by 1) supporting work to estimate the nutritional carrying capacity (NCC; i.e., the forage available to a population within a specified area and time) of the Delta, and 2) by exploring the feasibility of mechanical treatment as a means of stimulating browse production for the moose. Thus, the objectives of this thesis were to 1) explore the factors influencing NCC for moose on the west CRD while combining updated digital and field-collected data to estimate NCC, and 2) to assess the effects of mechanical treatment on the production of moose browse across stand types and over time. We collected field data and evaluated differences in the past (1988-89) and present (2012-13) biomass-predicting regression equations for two willow species (Barclay's and Hooker's willow, Salix barclayi and hookeriana) used within NCC models to determine 1) whether past and present models of Barclay's willow predicted similarly and 2) whether Hooker’s and Barclay's willow differed in average available biomass, nutritional quality, and utilization by moose. The linear coefficients for the current (2013) Barclay’s willow, Hooker's willow, and combined equations were 2.2x, 1.6x, and 1.9x larger, respectively, than that derived from the 1988 model for Barclay’s willow (which possibly included Hooker's willow data). Thus, willows on the CRD may now be supporting more biomass per stem than predicted by prior models. Hooker's and Barclay's willow did not differ in mean available biomass, nutritional values, or utilization rates. These results suggest a need to evaluate the accuracy of older allometric regressions, though separate identification of the visually-similar Barclay's and Hooker's willow may be unnecessary for future biomass-estimating efforts on the CRD. To further explore the factors influencing the biomass available to moose and their associated NCC estimates, we compared 5 NCC model types across 4 winter ranges and under 3 winter-severity scenarios for the western CRD moose population. We conducted a sensitivity analysis (Sx) of our final model to determine the relative influence of factors affecting NCC estimates. Lastly, we compared current (2012-13) browse available biomass, stand type areas (2011), and NCC results to those obtained by past research (1987-89, MacCracken et al. 1997 and 1959/1986, Stephenson et al. 2006) to determine changes over time, while evaluating the effects of models incorporating satellite-based estimates of stand areas and forage nutritional values on NCC estimates. Because recent aerial survey observations suggest expansion of the moose winter range, our final model estimated NCC between 2,198-3,471 moose depending on winter severity within a winter range encompassing the entire west Delta. These results suggest the current western moose population (approximately 600 in 2013) is below NCC. Model components with the largest and smallest Sx were snow depth and tannin- and lignin-caused reductions in forage nutritional quality, respectively. Changes from 1987-2013 in available biomass of forage species ranged from -66-493%, while changes from 1959-2011 in stand type areas ranged from -60-661%. Overall, NCC estimates only declined by 2% from 1959-2013, however inclusion of forage nutritional quality in models reduced NCC estimates by 60%. Lastly, we assessed the use of hydraulic-axing (i.e., hydro-axing) as tool for increasing the available willow biomass. We evaluated treatment effects on biomass, height, nutritional quality (crude protein, lignin, and tannin levels), utilization, and snow burial of the winter forage species within 3 winter-severity scenarios. Sites were treated in 4 winters (1990-92, 2008, 2010, and 2012) within 5 stand types in 20 locations varying from 0.86-63.40 ha in size. Results indicate few significant differences relative to controls, though treatment significantly increased the ratio of willow to alder. Our results may be limited by sample sizes (n = 1-9 per stand type or treatment year) as visual comparison suggests treatment via hydraulic-axing may be an effective method for increasing willow biomass without influencing nutritional quality. However, willows 20-23 years post-treatment are still significantly shorter than untreated willows (P = 0.03). Thus, treatment may result in decreased forage available to moose in severe winters. Management concerns regarding continued earthquake-initiated changes in vegetation distributions and successional processes prompted our investigation. However, studies on the vegetation dynamics of the CRD suggest the vegetation distribution of the Delta may be relatively stable (Boggs 2000, Thilenius 2008). If so, our current estimates of NCC suggest the west Delta can support a larger moose population than is currently present. Hydro-axing may not be necessary to ensure the future of the moose population, though it could be used to counter increases in alder (Alnus viridis sinuata) which are likely within certain successional sequences. However, together with earthquakes, the processes determining the future forage available on the CRD include complex, interactive forces such as glaciers, the Copper River, oceanic tides, and zoological- and human-caused influences. These forces and their effects on the vegetation create a dynamic ecosystem for the moose population, are difficult to predict, and may be further complicated by climate change. As a result, application of any managerial tool may be temporary and often difficult. However, this guarantees a constant need for further revision and redevelopment of the tools used to manage the moose population, ensuring that the moose of the CRD will remain an important resource for researching and refining ungulate management worldwide. Title: Evaluating tools used to estimate and manage browse available to wintering moose on the Copper River Delta, Alaska Author: Smythe, Sharon E. Ungulates comprise some of the most well researched and intensely managed wildlife populations on earth. As such, they are recognized as ideal study subjects for developing and modifying management tools or theories (Danell et al. 1994, Shipley 2010). An introduced moose (Alces alces gigas) population on the Copper River Delta (CRD; Delta) of south-central Alaska functions as a valuable resource for the residents of Cordova and an isolated research population on which to test managerial techniques. Since its introduction (1949-1958), the founding population of 23 moose has grown to over 830 in 2013, divided into two sub-populations. However, in 1964, the largest earthquake recorded in U.S. history (9.2 magnitude) uplifted the Delta by 1.0-4.0 m, initiating delta-wide changes in hydrology, vegetation distributions, and successional processes. The proportion of stands dominated by woody species, especially alder (Alnus viridis sinuata) and spruce (Picea sitchensis), increased visibly. Furthermore, previous research (1987-89) observed that 90% of the moose on the western region of the Delta wintered within 9-24% of the total land area, possibly restricting their available winter browse. Because moose diets on the CRD are dominated by willows (Salix spp.), managers were concerned that the combined effects of a restricted winter range and earthquake-initiated vegetation changes would negatively influence the population. Managers have responded to this concern by 1) supporting work to estimate the nutritional carrying capacity (NCC; i.e., the forage available to a population within a specified area and time) of the Delta, and 2) by exploring the feasibility of mechanical treatment as a means of stimulating browse production for the moose. Thus, the objectives of this thesis were to 1) explore the factors influencing NCC for moose on the west CRD while combining updated digital and field-collected data to estimate NCC, and 2) to assess the effects of mechanical treatment on the production of moose browse across stand types and over time. We collected field data and evaluated differences in the past (1988-89) and present (2012-13) biomass-predicting regression equations for two willow species (Barclay's and Hooker's willow, Salix barclayi and hookeriana) used within NCC models to determine 1) whether past and present models of Barclay's willow predicted similarly and 2) whether Hooker’s and Barclay's willow differed in average available biomass, nutritional quality, and utilization by moose. The linear coefficients for the current (2013) Barclay’s willow, Hooker's willow, and combined equations were 2.2x, 1.6x, and 1.9x larger, respectively, than that derived from the 1988 model for Barclay’s willow (which possibly included Hooker's willow data). Thus, willows on the CRD may now be supporting more biomass per stem than predicted by prior models. Hooker's and Barclay's willow did not differ in mean available biomass, nutritional values, or utilization rates. These results suggest a need to evaluate the accuracy of older allometric regressions, though separate identification of the visually-similar Barclay's and Hooker's willow may be unnecessary for future biomass-estimating efforts on the CRD. To further explore the factors influencing the biomass available to moose and their associated NCC estimates, we compared 5 NCC model types across 4 winter ranges and under 3 winter-severity scenarios for the western CRD moose population. We conducted a sensitivity analysis (Sx) of our final model to determine the relative influence of factors affecting NCC estimates. Lastly, we compared current (2012-13) browse available biomass, stand type areas (2011), and NCC results to those obtained by past research (1987-89, MacCracken et al. 1997 and 1959/1986, Stephenson et al. 2006) to determine changes over time, while evaluating the effects of models incorporating satellite-based estimates of stand areas and forage nutritional values on NCC estimates. Because recent aerial survey observations suggest expansion of the moose winter range, our final model estimated NCC between 2,198-3,471 moose depending on winter severity within a winter range encompassing the entire west Delta. These results suggest the current western moose population (approximately 600 in 2013) is below NCC. Model components with the largest and smallest Sx were snow depth and tannin- and lignin-caused reductions in forage nutritional quality, respectively. Changes from 1987-2013 in available biomass of forage species ranged from -66-493%, while changes from 1959-2011 in stand type areas ranged from -60-661%. Overall, NCC estimates only declined by 2% from 1959-2013, however inclusion of forage nutritional quality in models reduced NCC estimates by 60%. Lastly, we assessed the use of hydraulic-axing (i.e., hydro-axing) as tool for increasing the available willow biomass. We evaluated treatment effects on biomass, height, nutritional quality (crude protein, lignin, and tannin levels), utilization, and snow burial of the winter forage species within 3 winter-severity scenarios. Sites were treated in 4 winters (1990-92, 2008, 2010, and 2012) within 5 stand types in 20 locations varying from 0.86-63.40 ha in size. Results indicate few significant differences relative to controls, though treatment significantly increased the ratio of willow to alder. Our results may be limited by sample sizes (n = 1-9 per stand type or treatment year) as visual comparison suggests treatment via hydraulic-axing may be an effective method for increasing willow biomass without influencing nutritional quality. However, willows 20-23 years post-treatment are still significantly shorter than untreated willows (P = 0.03). Thus, treatment may result in decreased forage available to moose in severe winters. Management concerns regarding continued earthquake-initiated changes in vegetation distributions and successional processes prompted our investigation. However, studies on the vegetation dynamics of the CRD suggest the vegetation distribution of the Delta may be relatively stable (Boggs 2000, Thilenius 2008). If so, our current estimates of NCC suggest the west Delta can support a larger moose population than is currently present. Hydro-axing may not be necessary to ensure the future of the moose population, though it could be used to counter increases in alder (Alnus viridis sinuata) which are likely within certain successional sequences. However, together with earthquakes, the processes determining the future forage available on the CRD include complex, interactive forces such as glaciers, the Copper River, oceanic tides, and zoological- and human-caused influences. These forces and their effects on the vegetation create a dynamic ecosystem for the moose population, are difficult to predict, and may be further complicated by climate change. As a result, application of any managerial tool may be temporary and often difficult. However, this guarantees a constant need for further revision and redevelopment of the tools used to manage the moose population, ensuring that the moose of the CRD will remain an important resource for researching and refining ungulate management worldwide. Close

• 1557. [Article] Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon

  First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations ...

  Citation × Citation Citation Abstract Copy Title: Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon Author: Arsan, E. Leyla First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations in the intermountain west. Recent development of risk assessment models used to assess the likelihood and consequences of exotic parasite introduction, have strengthened the process of science-based decision-making in aquatic animal health. In the case of M. cerebralis, it is necessary to use a risk assessment model with two unique segments that clearly address the distinct life stages and respective hosts of the parasite separately. The studies described examine the probability of M. cerebralis introduction and establishment for two regions: the state of Alaska, and the Willamette River basin, Oregon. The Alaska risk assessment was based on the assumption that the parasite did not already occur in the state. However, in the process of validating this assumption, we documented the first polymerase chain reaction (PCR) detection of the parasite in the state. The pathogen was identified in hatchery rainbow trout (Oncorhynchus mykiss) from the Anchorage area. Although this is the first detection of the parasite in Alaska, clinical whirling disease has never been documented in the state. To qualitatively assess the risk of further spread of M. cerebralis in Alaska, four potential routes of dissemination were examined: movement of fish by humans, natural dispersal (via migratory birds and stray anadromous salmon), recreational activities, and commercial seafood processing. This research indicates the most likely pathway for M. cerebralis transport in Alaska is human movement of fish. In the Willamette River basin, Oregon, introduction of M. cerebralis has already occurred, though establishment appears limited to a single private hatchery. Introduction in this region was considered the most likely to occur as a result of human movements of fish. Straying anadromous salmonids were also assessed and were present in higher numbers than predicted. However, they were not infected with the parasite, and thus the probability for introduction by this route is low. The probability of introduction of the parasite varies throughout the Willamette River basin. Areas with the highest probability for M. cerebralis introduction were identified as the Clackamas and Santiam River subbasins. The Clackamas River has already experienced an introduction of the parasite, has the largest concentration of hatcheries (state, federal, and private), has a popular sport fishery, and is the closest major tributary to the enormous piscivorous bird-populations in the Columbia River estuary. The Santiam subbasin has a popular sport fishery, received the highest number of stray fish in the Willamette River basin, and has the second largest concentration of hatcheries in the Willamette River basin. Unique from introduction, establishment of the parasite is dependent upon several environmental and biological factors including: water temperatures, spatial/temporal overlap of hosts, and the distribution and genetic composition of the parasite’s invertebrate host, Tubifex tubifex. The distribution, genetic composition and susceptibility of T. tubifex, were considered the most important factor in the ability of M. cerebralis to establish in both systems. Surveys of oligochaete populations were conducted in both study regions. In Alaska, T. tubifex was not detected from the southeast region and the apparent lack of appropriate tubificid hosts may prevent establishment in that part of the state. However, 4 lineages (I, III, IV, and VI) of the species were identified from southcentral Alaska. Lineage IV has not been previously been described in North America and its susceptibility to M. cerebralis was unknown. When lineage IV T. tubifex and 3 mixed-lineage (I, III, IV and VI) groups were exposed to M. cerebralis, only lineage III became infected under our experimental conditions. Thus, if the parasite were dispersed, conditions are appropriate for establishment and propagation of the parasite life cycle in southcentral Alaska, although detrimental effects on fish populations may be reduced as a result of the presence of non-susceptible lineages of T. tubifex. The probability of further establishment in this area is greatest in Ship Creek, where the abundance of susceptible T. tubifex, the presence of susceptible rainbow trout (Oncorhynchus mykiss), and the proximity to the known area of infection make conditions particularly appropriate. Similar to findings in Alaska, the Willamette River basin, Oregon also supports populations of susceptible T. tubifex. If the pathogen were introduced, probability of establishment is high in certain areas of the basin as all conditions are appropriate for propagation of the parasite life cycle. Tributaries to the mainstem Willamette River have the highest probability of establishment as these areas have the greatest numbers of susceptible T. tubifex. However, the abundance of resistant strains of T. tubifex could mitigate the effects of M. cerebralis if introduced. Management recommendations to reduce the likelihood of parasite dissemination are similar for Oregon and Alaska since human movement of fish and angler activities were considered the most likely routes of introduction for both regions. Based on this research, steps should also be taken to limit human movement of fish, whether by restricting carcass planting for stream enrichment in Oregon, or by prohibiting use of fish heads as bait in southcentral Alaska. The states should also allot resources to angler education and awareness of the effects of angler activity and recreation on dispersal of M. cerebralis. This could be done using a combination of brochures and signage at boat ramps describing how to prevent spread of aquatic nuisance species. Title: Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon Author: Arsan, E. Leyla First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations in the intermountain west. Recent development of risk assessment models used to assess the likelihood and consequences of exotic parasite introduction, have strengthened the process of science-based decision-making in aquatic animal health. In the case of M. cerebralis, it is necessary to use a risk assessment model with two unique segments that clearly address the distinct life stages and respective hosts of the parasite separately. The studies described examine the probability of M. cerebralis introduction and establishment for two regions: the state of Alaska, and the Willamette River basin, Oregon. The Alaska risk assessment was based on the assumption that the parasite did not already occur in the state. However, in the process of validating this assumption, we documented the first polymerase chain reaction (PCR) detection of the parasite in the state. The pathogen was identified in hatchery rainbow trout (Oncorhynchus mykiss) from the Anchorage area. Although this is the first detection of the parasite in Alaska, clinical whirling disease has never been documented in the state. To qualitatively assess the risk of further spread of M. cerebralis in Alaska, four potential routes of dissemination were examined: movement of fish by humans, natural dispersal (via migratory birds and stray anadromous salmon), recreational activities, and commercial seafood processing. This research indicates the most likely pathway for M. cerebralis transport in Alaska is human movement of fish. In the Willamette River basin, Oregon, introduction of M. cerebralis has already occurred, though establishment appears limited to a single private hatchery. Introduction in this region was considered the most likely to occur as a result of human movements of fish. Straying anadromous salmonids were also assessed and were present in higher numbers than predicted. However, they were not infected with the parasite, and thus the probability for introduction by this route is low. The probability of introduction of the parasite varies throughout the Willamette River basin. Areas with the highest probability for M. cerebralis introduction were identified as the Clackamas and Santiam River subbasins. The Clackamas River has already experienced an introduction of the parasite, has the largest concentration of hatcheries (state, federal, and private), has a popular sport fishery, and is the closest major tributary to the enormous piscivorous bird-populations in the Columbia River estuary. The Santiam subbasin has a popular sport fishery, received the highest number of stray fish in the Willamette River basin, and has the second largest concentration of hatcheries in the Willamette River basin. Unique from introduction, establishment of the parasite is dependent upon several environmental and biological factors including: water temperatures, spatial/temporal overlap of hosts, and the distribution and genetic composition of the parasite’s invertebrate host, Tubifex tubifex. The distribution, genetic composition and susceptibility of T. tubifex, were considered the most important factor in the ability of M. cerebralis to establish in both systems. Surveys of oligochaete populations were conducted in both study regions. In Alaska, T. tubifex was not detected from the southeast region and the apparent lack of appropriate tubificid hosts may prevent establishment in that part of the state. However, 4 lineages (I, III, IV, and VI) of the species were identified from southcentral Alaska. Lineage IV has not been previously been described in North America and its susceptibility to M. cerebralis was unknown. When lineage IV T. tubifex and 3 mixed-lineage (I, III, IV and VI) groups were exposed to M. cerebralis, only lineage III became infected under our experimental conditions. Thus, if the parasite were dispersed, conditions are appropriate for establishment and propagation of the parasite life cycle in southcentral Alaska, although detrimental effects on fish populations may be reduced as a result of the presence of non-susceptible lineages of T. tubifex. The probability of further establishment in this area is greatest in Ship Creek, where the abundance of susceptible T. tubifex, the presence of susceptible rainbow trout (Oncorhynchus mykiss), and the proximity to the known area of infection make conditions particularly appropriate. Similar to findings in Alaska, the Willamette River basin, Oregon also supports populations of susceptible T. tubifex. If the pathogen were introduced, probability of establishment is high in certain areas of the basin as all conditions are appropriate for propagation of the parasite life cycle. Tributaries to the mainstem Willamette River have the highest probability of establishment as these areas have the greatest numbers of susceptible T. tubifex. However, the abundance of resistant strains of T. tubifex could mitigate the effects of M. cerebralis if introduced. Management recommendations to reduce the likelihood of parasite dissemination are similar for Oregon and Alaska since human movement of fish and angler activities were considered the most likely routes of introduction for both regions. Based on this research, steps should also be taken to limit human movement of fish, whether by restricting carcass planting for stream enrichment in Oregon, or by prohibiting use of fish heads as bait in southcentral Alaska. The states should also allot resources to angler education and awareness of the effects of angler activity and recreation on dispersal of M. cerebralis. This could be done using a combination of brochures and signage at boat ramps describing how to prevent spread of aquatic nuisance species. Close

• 1558. [Article] The biochemical oxygen demand of Douglas-fir needles and twigs, western hemlock needles and red alder leaves in stream water

  Field studies indicate that accumulation of finely divided organic debris in the channels of mountain streams after clearcutting may be responsible for subsequent reduction in the dissolved oxygen concentration. The ...

  Citation × Citation Citation Abstract Copy Title: The biochemical oxygen demand of Douglas-fir needles and twigs, western hemlock needles and red alder leaves in stream water Author: Ponce, Stanley L. Field studies indicate that accumulation of finely divided organic debris in the channels of mountain streams after clearcutting may be responsible for subsequent reduction in the dissolved oxygen concentration. The purpose of this study was to quantify the biochemical oxygen demand (BOD) of Douglas-fir needles and twigs, western hemlock needles and red alder leaves, ascertain the chemical characteristics of the leachate from these materials, and determine if such materials are toxic to fish. Long- and short-term BOD and BOD rate constants were determined for the different types of vegetation. A standard temperature BOD test was run 90 days for the leaf material and 45 days for the Douglas-fir twigs. Four replications were run for the leaves and three run for the twigs. Half the leaf samples were fixed with a nitrification inhibitor. However, later analyses proved nitrification did not occur. As a result, all the replications within a species were combined and one curve was fitted through each group of data. A BOD curve was constructed by least squares fit through the 90 days of leaf data and through 45 days of the twig data and extended to 90 days. The 90 day K1 and the B0D90 were calculated from this curve and were: 0. 125 and 110 mg 02/gm (dry weight) for Douglas-fir needles, 0.056 and 110 mg 02/gm (dry weight) for Douglas-fir twigs, 0.064 and 166 mg 02/gm (dry weight) for western hemlock needles, and 0. 046 and 286 mg 02/gm (dry weight) for red alder leaves. Further tests showed that these 90 day values could be accurately estimated by tests of shorter duration; 20 days for Douglas-fir and western hemlock, and 60 days for red alder. The 20-day western hemlock values may, in fact, yield a more precise estimate of the actual 90-day values than the composite fit. The 20-day western hemlock projections were 0.049 for K1 and 200 mg O2Igm (dry weight) for the B0D90. Leachates of the test materials were analyzed with respect to composition, concentration, and rate of nutrient release. This information was to be used in the explanation of the 90 day BOD values obtained. Half the samples were poisoned with 2. 7 mg/l mercuric chloride to inhibit microorganism growth while the rest of the samples remained untreated to show the effect of the microorganisms. These data were of limited use due to fungal growths appearing after 20 days and failure of half the twig samples to be adequately poisoned. The test was terminated after 20 days. Simple sugars and phenolic compounds were found in all the samples. Simple sugars present were arabinose, xylose, galactose, mannose, and glucose. Mean maximum sugar concentrations released in poisoned leaf samples varied from 21.5 mg glucose equivalent/gm (fresh weight) to 15. 0 mg/gm (fresh weight) for Douglas-fir and red alder. The mean maximum sugar concentrations in the non-poisoned samples were much less: 6. 0, 5. 0, and 8. 0 mg glucose equivalent/ gm (fresh weight) respectively for Douglas-fir, western hemlock, and red alder. The rate of sugar release was rapid for Douglas-fir needles, slow for red alder, and intermediate for western hemlock. The different types of phenolic compounds were not identified. The mean maximum concentration of phenolics in the poisoned samples were 0.72, 0.46, and 0.55 mg gallic acid/gm (fresh weight) respectively for Douglas-fir, western hemlock, and red alder leaves. There was little difference between mean concentrations of the poisoned and non-poisoned samples until day 10, at which time mean phenolic concentrations of the non-poisoned samples began to drop. The Douglas-fir twigs had a slow initial sugar release, followed by an increase in the rate; the maximum concentration reached was 10. 0 mg glucose equivalent/gm (fresh weight). The pattern of phenolic release was the same with a maximum concentration of about 1. 0 mg gallic acid/gm (fresh weight). The five-day BOD of leaf material was determined under conditions of fluctuating temperature (12. 8 to 35.00 C) similar to that observed in streams exposed by clearcutting. The BOD5 values were: 202 mg 02/gm (dry weight) for Douglas-fir, 109 mg 02/gm (dry weight) for western hemlock, and 249 mg 02/gm (dry weight) for red alder leaves. The BOD5 of samples incubated at standard temperature was much lower than those exposed to conditions of fluctuating temperature; it was 25, 42, and 24 percent of the temperature fluctuated BOD5 for Douglas-fir, western hemlock, and red alder leaves respectively. The toxicity of leachate extracted from 50 grams (fresh weight) per liter of water of each species was determined on guppies and steelhead fry. The 96-hr. LC5O to guppies from leachate of Douglas-fir, western hemlock, and red alder was 35, 65, and 18 percent of the original concentration as opposed to 26, 7. 5 and 25 percent of the original concentration for the steelhead fry. These are extremely low levels of toxicity to such a concentrated sample and pose no threat to the fish. Title: The biochemical oxygen demand of Douglas-fir needles and twigs, western hemlock needles and red alder leaves in stream water Author: Ponce, Stanley L. Field studies indicate that accumulation of finely divided organic debris in the channels of mountain streams after clearcutting may be responsible for subsequent reduction in the dissolved oxygen concentration. The purpose of this study was to quantify the biochemical oxygen demand (BOD) of Douglas-fir needles and twigs, western hemlock needles and red alder leaves, ascertain the chemical characteristics of the leachate from these materials, and determine if such materials are toxic to fish. Long- and short-term BOD and BOD rate constants were determined for the different types of vegetation. A standard temperature BOD test was run 90 days for the leaf material and 45 days for the Douglas-fir twigs. Four replications were run for the leaves and three run for the twigs. Half the leaf samples were fixed with a nitrification inhibitor. However, later analyses proved nitrification did not occur. As a result, all the replications within a species were combined and one curve was fitted through each group of data. A BOD curve was constructed by least squares fit through the 90 days of leaf data and through 45 days of the twig data and extended to 90 days. The 90 day K1 and the B0D90 were calculated from this curve and were: 0. 125 and 110 mg 02/gm (dry weight) for Douglas-fir needles, 0.056 and 110 mg 02/gm (dry weight) for Douglas-fir twigs, 0.064 and 166 mg 02/gm (dry weight) for western hemlock needles, and 0. 046 and 286 mg 02/gm (dry weight) for red alder leaves. Further tests showed that these 90 day values could be accurately estimated by tests of shorter duration; 20 days for Douglas-fir and western hemlock, and 60 days for red alder. The 20-day western hemlock values may, in fact, yield a more precise estimate of the actual 90-day values than the composite fit. The 20-day western hemlock projections were 0.049 for K1 and 200 mg O2Igm (dry weight) for the B0D90. Leachates of the test materials were analyzed with respect to composition, concentration, and rate of nutrient release. This information was to be used in the explanation of the 90 day BOD values obtained. Half the samples were poisoned with 2. 7 mg/l mercuric chloride to inhibit microorganism growth while the rest of the samples remained untreated to show the effect of the microorganisms. These data were of limited use due to fungal growths appearing after 20 days and failure of half the twig samples to be adequately poisoned. The test was terminated after 20 days. Simple sugars and phenolic compounds were found in all the samples. Simple sugars present were arabinose, xylose, galactose, mannose, and glucose. Mean maximum sugar concentrations released in poisoned leaf samples varied from 21.5 mg glucose equivalent/gm (fresh weight) to 15. 0 mg/gm (fresh weight) for Douglas-fir and red alder. The mean maximum sugar concentrations in the non-poisoned samples were much less: 6. 0, 5. 0, and 8. 0 mg glucose equivalent/ gm (fresh weight) respectively for Douglas-fir, western hemlock, and red alder. The rate of sugar release was rapid for Douglas-fir needles, slow for red alder, and intermediate for western hemlock. The different types of phenolic compounds were not identified. The mean maximum concentration of phenolics in the poisoned samples were 0.72, 0.46, and 0.55 mg gallic acid/gm (fresh weight) respectively for Douglas-fir, western hemlock, and red alder leaves. There was little difference between mean concentrations of the poisoned and non-poisoned samples until day 10, at which time mean phenolic concentrations of the non-poisoned samples began to drop. The Douglas-fir twigs had a slow initial sugar release, followed by an increase in the rate; the maximum concentration reached was 10. 0 mg glucose equivalent/gm (fresh weight). The pattern of phenolic release was the same with a maximum concentration of about 1. 0 mg gallic acid/gm (fresh weight). The five-day BOD of leaf material was determined under conditions of fluctuating temperature (12. 8 to 35.00 C) similar to that observed in streams exposed by clearcutting. The BOD5 values were: 202 mg 02/gm (dry weight) for Douglas-fir, 109 mg 02/gm (dry weight) for western hemlock, and 249 mg 02/gm (dry weight) for red alder leaves. The BOD5 of samples incubated at standard temperature was much lower than those exposed to conditions of fluctuating temperature; it was 25, 42, and 24 percent of the temperature fluctuated BOD5 for Douglas-fir, western hemlock, and red alder leaves respectively. The toxicity of leachate extracted from 50 grams (fresh weight) per liter of water of each species was determined on guppies and steelhead fry. The 96-hr. LC5O to guppies from leachate of Douglas-fir, western hemlock, and red alder was 35, 65, and 18 percent of the original concentration as opposed to 26, 7. 5 and 25 percent of the original concentration for the steelhead fry. These are extremely low levels of toxicity to such a concentrated sample and pose no threat to the fish. Close

• 1559. [Article] Insights into the Geochemical Evolution of the Youngest Toba Tuff (Sumatra, Indonesia) Magma Chamber Through the Lens of Zircon-hosted Melt Inclusions

  Supervolcanic eruptions are among the most catastrophic phenomena on Earth, erupting 100s-1000s of cubic kilometers of magma, and producing devastating local effects and global climate perturbations. The ...

  Citation × Citation Citation Abstract Copy Title: Insights into the Geochemical Evolution of the Youngest Toba Tuff (Sumatra, Indonesia) Magma Chamber Through the Lens of Zircon-hosted Melt Inclusions Author: Lerner, Allan (Allan Henry) Supervolcanic eruptions are among the most catastrophic phenomena on Earth, erupting 100s-1000s of cubic kilometers of magma, and producing devastating local effects and global climate perturbations. The largest supervolcanic eruption of the last 28 Ma was the 74 ka Youngest Toba Tuff (YTT) eruption from Sumatra, Indonesia, which erupted 2,800 – 5,300 km³ of magma and may have pushed the human species to the brink of extinction. Despite the global significance of such events, the magmatic evolution that builds to super-eruptions remains poorly understood. The mineral zircon provides a unique potential to gain multidimensional insights into the pre-eruptive evolution of magma chambers by combining mineral and melt inclusion chemistry with U-series mineral dating. We combine zircon U-Th dating and trace element chemistry with zircon-hosted melt inclusion chemistries and volatile abundances to investigate the magmatic evolution preceding the YTT eruption To begin, we present the first detailed study of the susceptibility of zircon-hosted inclusions to syn- or post-entrapment modification of melt compositions. We conclude that boundary layer effects are negligible in even very small zircon-hosted inclusions owing to the slow growth rate of zircon crystals. Post-entrapment crystallization (PEC) of the zircon host phase is also a trivial concern, owing to the low Zr content of most melts. PEC of other daughter phases is recognized (< ~2% amphibole and sanidine), but these effects are also minor relative to melt inclusions in many major-phase minerals. The diffusive exchange of water from zircon-hosted melt inclusions is modeled to occur in less than 10 ka, and requilibration may occur within decades-centuries. Therefore, water contents of zircon-hosted inclusions represent late-stage storage conditions rather than long-term records of magmatic water. Zircon-hosted inclusions should remain diffusively sealed to all melt species, apart from H⁺, He, and Li⁺, over typical magmatic system timescales (104-105 yrs). Therefore, we conclude that zircon is a robust, albeit small, melt inclusion host and entrapped inclusions will be largely representative of the melt environments in which they formed. We then apply the multidimensional utility of zircon to gain insights into the pre-eruptive evolution of the YTT magmatic system. YTT zircon grains have U-Th crystallization ages spanning from the ~74 ka eruption age to > 375 ka, reinforcing earlier findings that the YTT system was long-lived. A progressive increase of U in zircon growth zones from < 500 to ~1,500 ppm indicates that the YTT system, or a portion of it, became highly fractionated between 130-200 ka. A lull in zircon formation between ~110-130 ka is contemporaneous with a previously recognized increase in chemical diversity of allanite, possibly reflecting a period of enhanced thermal input into the system. We identify two main populations of zircon-hosted melt inclusions. A low-MgO type is chemically evolved (> 280 ppm Rb, ~125 ppm Ba, 25-30 ppm Sr, < 0.03 wt% MgO) and has high water contents (3.8-5.7 wt% H₂O), consistent with formation and storage in a highly fractionated crystal mush ~4-9 km deep. A high-MgO type (250-260 ppm Rb, 160-450 ppm Ba, 35-55 ppm Sr, 0.04-0.07 wt% MgO) has compositions similar to matrix glasses, and is typically less hydrous (0.5-3.5 wt% H₂O), suggesting shallow (< 3 km) formation, storage, and syn-eruptive degassing in a less evolved melt. Melt inclusions dated via U-Th measurements of their entrapping zircon zones show no clear temporal differences between the two MgO populations. Rather, melt inclusions entrapped throughout the entire YTT history have relatively invariant major element compositions, and also have no discernible temporal trends in volatile abundances. We largely attribute these findings to the narrow stability field in which zircon crystallize, which inherently limits the compositional range of zircon-hosted inclusions. Zircon-hosted melt inclusions (particularly the high-MgO type) of many ages occur within sealed reentrant melt-channels. This suggests that melt inclusions in YTT zircon grains commonly formed as the system re-established zircon saturation following periods of zircon dissolution during thermal recharge events. A number of zircon grains have melt channels actively open to the grain exterior, which are rimmed with 1-3 μm of cathodoluminescence-bright (low-U) zircon growth. These dissolution/regrowth features are texturally similar to dissolution zones and high-temperature overgrowths described previously in YTT quartz; collectively, these textures provide evidence of a major thermal perturbation(s) 10s-100s of years before the YTT eruption. We conclude that high-T, mafic recharge events occurred throughout the pre-eruptive YTT evolution, and suggest that one or more large recharge events triggered the cataclysmic 74 ka YTT eruption. Title: Insights into the Geochemical Evolution of the Youngest Toba Tuff (Sumatra, Indonesia) Magma Chamber Through the Lens of Zircon-hosted Melt Inclusions Author: Lerner, Allan (Allan Henry) Supervolcanic eruptions are among the most catastrophic phenomena on Earth, erupting 100s-1000s of cubic kilometers of magma, and producing devastating local effects and global climate perturbations. The largest supervolcanic eruption of the last 28 Ma was the 74 ka Youngest Toba Tuff (YTT) eruption from Sumatra, Indonesia, which erupted 2,800 – 5,300 km³ of magma and may have pushed the human species to the brink of extinction. Despite the global significance of such events, the magmatic evolution that builds to super-eruptions remains poorly understood. The mineral zircon provides a unique potential to gain multidimensional insights into the pre-eruptive evolution of magma chambers by combining mineral and melt inclusion chemistry with U-series mineral dating. We combine zircon U-Th dating and trace element chemistry with zircon-hosted melt inclusion chemistries and volatile abundances to investigate the magmatic evolution preceding the YTT eruption To begin, we present the first detailed study of the susceptibility of zircon-hosted inclusions to syn- or post-entrapment modification of melt compositions. We conclude that boundary layer effects are negligible in even very small zircon-hosted inclusions owing to the slow growth rate of zircon crystals. Post-entrapment crystallization (PEC) of the zircon host phase is also a trivial concern, owing to the low Zr content of most melts. PEC of other daughter phases is recognized (< ~2% amphibole and sanidine), but these effects are also minor relative to melt inclusions in many major-phase minerals. The diffusive exchange of water from zircon-hosted melt inclusions is modeled to occur in less than 10 ka, and requilibration may occur within decades-centuries. Therefore, water contents of zircon-hosted inclusions represent late-stage storage conditions rather than long-term records of magmatic water. Zircon-hosted inclusions should remain diffusively sealed to all melt species, apart from H⁺, He, and Li⁺, over typical magmatic system timescales (104-105 yrs). Therefore, we conclude that zircon is a robust, albeit small, melt inclusion host and entrapped inclusions will be largely representative of the melt environments in which they formed. We then apply the multidimensional utility of zircon to gain insights into the pre-eruptive evolution of the YTT magmatic system. YTT zircon grains have U-Th crystallization ages spanning from the ~74 ka eruption age to > 375 ka, reinforcing earlier findings that the YTT system was long-lived. A progressive increase of U in zircon growth zones from < 500 to ~1,500 ppm indicates that the YTT system, or a portion of it, became highly fractionated between 130-200 ka. A lull in zircon formation between ~110-130 ka is contemporaneous with a previously recognized increase in chemical diversity of allanite, possibly reflecting a period of enhanced thermal input into the system. We identify two main populations of zircon-hosted melt inclusions. A low-MgO type is chemically evolved (> 280 ppm Rb, ~125 ppm Ba, 25-30 ppm Sr, < 0.03 wt% MgO) and has high water contents (3.8-5.7 wt% H₂O), consistent with formation and storage in a highly fractionated crystal mush ~4-9 km deep. A high-MgO type (250-260 ppm Rb, 160-450 ppm Ba, 35-55 ppm Sr, 0.04-0.07 wt% MgO) has compositions similar to matrix glasses, and is typically less hydrous (0.5-3.5 wt% H₂O), suggesting shallow (< 3 km) formation, storage, and syn-eruptive degassing in a less evolved melt. Melt inclusions dated via U-Th measurements of their entrapping zircon zones show no clear temporal differences between the two MgO populations. Rather, melt inclusions entrapped throughout the entire YTT history have relatively invariant major element compositions, and also have no discernible temporal trends in volatile abundances. We largely attribute these findings to the narrow stability field in which zircon crystallize, which inherently limits the compositional range of zircon-hosted inclusions. Zircon-hosted melt inclusions (particularly the high-MgO type) of many ages occur within sealed reentrant melt-channels. This suggests that melt inclusions in YTT zircon grains commonly formed as the system re-established zircon saturation following periods of zircon dissolution during thermal recharge events. A number of zircon grains have melt channels actively open to the grain exterior, which are rimmed with 1-3 μm of cathodoluminescence-bright (low-U) zircon growth. These dissolution/regrowth features are texturally similar to dissolution zones and high-temperature overgrowths described previously in YTT quartz; collectively, these textures provide evidence of a major thermal perturbation(s) 10s-100s of years before the YTT eruption. We conclude that high-T, mafic recharge events occurred throughout the pre-eruptive YTT evolution, and suggest that one or more large recharge events triggered the cataclysmic 74 ka YTT eruption. Close

• 1560. [Article] Hawaiian duck (Anas wyvilliana) behavior and response to wetland habitat management at Hanalei National Wildlife Refuge on Kaua'i

  The endangered Hawaiian Duck (koloa maoli; Anas wyvilliana), a non-migratory and island-endemic species, experienced a significant population decline during the twentieth century due to factors such as ...

  Citation × Citation Citation Abstract Copy Title: Hawaiian duck (Anas wyvilliana) behavior and response to wetland habitat management at Hanalei National Wildlife Refuge on Kaua'i Author: Malachowski, Christopher P. The endangered Hawaiian Duck (koloa maoli; Anas wyvilliana), a non-migratory and island-endemic species, experienced a significant population decline during the twentieth century due to factors such as habitat loss, overharvest, introduced mammalian predators, and hybridization with introduced feral Mallards (A. platyrhynchos). A key objective for Hawaiian Duck recovery is to establish a protected and managed network of wetland habitats; however, development of effective habitat management plans is stymied by the lack of information on patterns of habitat use in relation to fundamental resource requirements. Furthermore, many generalizations regarding dabbling duck behavior and resource requirements that guide seasonal wetland management objectives in North America may not apply to tropical regions and island systems. In this thesis, I compare the behavioral repertoire of the Hawaiian Duck with closely related island-endemic waterfowl and migratory North American Anas, I investigate the behavioral response of Hawaiian Ducks to wetland habitat management and taro cultivation, and I examine the effects of environmental, climatic, temporal, and social factors on the activity budgets of Hawaiian Ducks. I conducted instantaneous focal sampling (n = 984 observation sessions; 328.8 hr) throughout the annual cycle from September 2010 to August 2011 at managed wetlands and taro lo'i within Hanalei National Wildlife Refuge (NWR), Kaua'i. I documented 73 specific Hawaiian Duck behaviors in eight broad behavior categories including foraging, maintenance, resting, locomotion, alert, courtship, and intraspecific and interspecific agonistic interactions. I found that the behavioral repertoire of the Hawaiian Duck was similar to that of the Mallard; however, subtle variations in the form and linkage of certain courtship displays, such as nod-swimming, were observed. Additionally, male Hawaiian Ducks were occasionally associated with brood-rearing females (11% of brood observations), and this behavior appeared to be a male strategy whereby females received little perceived benefit , but males may have potentially garnered additional breeding attempts or maintained pair-bonds for subsequent breeding seasons. After accounting for sex, pair status, month, and time of day, the diurnal behavioral activities of Hawaiian Ducks differed between managed wetlands and taro habitats (F₆,₉₆₀ = 30.3, P < 0.001). Hawaiian Ducks utilized taro predominantly for resting (44%), maintenance (21%), and foraging (15%), while birds used managed wetlands for a variety of activities, including foraging (11%), maintenance (28%), resting (27%), and locomotion (22%). Social activities, particularly courtship, occurred more frequently in managed wetlands than in taro (H₁ = 11.9, P < 0.001). In managed wetlands, birds foraged slightly more with increasing cover of Cyperus spp. (r = 0.18, P < 0.001) and Fimbristylis littoralis (r = 0.17, P < 0.01) and decreasing cover of Urochloa mutica (r = -0.15, P < 0.01) and wetland vegetation height (r = -0.22, P < 0.001). Within taro habitat, the behavioral activities of Hawaiian Ducks differed significantly between birds in lo'i and on dikes (F₆,₄₆₈ = 142.8, P < 0.001); birds utilized lo‘i dikes for resting (60%) and maintenance activities (21%), whereas birds entered lo‘i primarily to forage (45%). The activity budget of Hawaiian Ducks was strongly influenced by time of day (F₁₈,₂₇₁₅.₇₈ = 6.4, P < 0.001), and birds spent more time engaged in active behaviors (i.e., foraging, locomotion, and alert) and less time resting during early morning and evening than during late morning and afternoon. While strong seasonal shifts in most behavioral patterns were not detected, males allocated more time to courting (1.1 vs. 0.3%; H1 = 6.92, P = 0.009) and mate-guarding (0.5 vs. <0.1%; H₁ = 9.83, P = 0.002) in managed wetlands between November and March than the remainder of the year. The effects of sex (F₆,₉₆₀ = 6.06, P < 0.001) and social status (F₆,₆₈₂ = 6.69, P < 0.001) on activity budgets were also significant. Females spent more time foraging (18 vs. 12%) and less time in alert, locomotor, and social behaviors than males. Paired birds allocated more time to aggression towards conspecifics, mate-guarding, and courtship, and within taro lo‘i, paired birds foraged more and rested less than unpaired birds. Overall, Hawaiian Duck allocated diurnal activity budgets differently in managed and cultivated wetland habitat at Hanalei NWR, suggesting that both systems may play an important role in fulfilling fundamental daily and seasonal resource requirements. The increased range of activities and foraging tactics used in managed wetlands may indicate the greater habitat diversity (e.g., vegetation structure, patchiness, plant species richness, range of water depths) provided by seasonal wetlands. In general, Hawaiian Duck allocated less time to diurnal foraging than North American Anas, such Mallard and Mottled Duck (A. fulvigula), suggesting that Hawaiian Duck may have lower daily and seasonal energy demands, have access to higher quality diet, or allot more time to nocturnal foraging activities. Also, unlike many North American migratory waterfowl that demonstrate significant behavioral plasticity in adjusting activity budgets to meet seasonal energy demands associated with breeding, molting, wintering, and migration, Hawaiian Duck did not exhibit a strong seasonal shift in most behaviors which may reflect their non-migratory nature and asynchronous life history cycle. Title: Hawaiian duck (Anas wyvilliana) behavior and response to wetland habitat management at Hanalei National Wildlife Refuge on Kaua'i Author: Malachowski, Christopher P. The endangered Hawaiian Duck (koloa maoli; Anas wyvilliana), a non-migratory and island-endemic species, experienced a significant population decline during the twentieth century due to factors such as habitat loss, overharvest, introduced mammalian predators, and hybridization with introduced feral Mallards (A. platyrhynchos). A key objective for Hawaiian Duck recovery is to establish a protected and managed network of wetland habitats; however, development of effective habitat management plans is stymied by the lack of information on patterns of habitat use in relation to fundamental resource requirements. Furthermore, many generalizations regarding dabbling duck behavior and resource requirements that guide seasonal wetland management objectives in North America may not apply to tropical regions and island systems. In this thesis, I compare the behavioral repertoire of the Hawaiian Duck with closely related island-endemic waterfowl and migratory North American Anas, I investigate the behavioral response of Hawaiian Ducks to wetland habitat management and taro cultivation, and I examine the effects of environmental, climatic, temporal, and social factors on the activity budgets of Hawaiian Ducks. I conducted instantaneous focal sampling (n = 984 observation sessions; 328.8 hr) throughout the annual cycle from September 2010 to August 2011 at managed wetlands and taro lo'i within Hanalei National Wildlife Refuge (NWR), Kaua'i. I documented 73 specific Hawaiian Duck behaviors in eight broad behavior categories including foraging, maintenance, resting, locomotion, alert, courtship, and intraspecific and interspecific agonistic interactions. I found that the behavioral repertoire of the Hawaiian Duck was similar to that of the Mallard; however, subtle variations in the form and linkage of certain courtship displays, such as nod-swimming, were observed. Additionally, male Hawaiian Ducks were occasionally associated with brood-rearing females (11% of brood observations), and this behavior appeared to be a male strategy whereby females received little perceived benefit , but males may have potentially garnered additional breeding attempts or maintained pair-bonds for subsequent breeding seasons. After accounting for sex, pair status, month, and time of day, the diurnal behavioral activities of Hawaiian Ducks differed between managed wetlands and taro habitats (F₆,₉₆₀ = 30.3, P < 0.001). Hawaiian Ducks utilized taro predominantly for resting (44%), maintenance (21%), and foraging (15%), while birds used managed wetlands for a variety of activities, including foraging (11%), maintenance (28%), resting (27%), and locomotion (22%). Social activities, particularly courtship, occurred more frequently in managed wetlands than in taro (H₁ = 11.9, P < 0.001). In managed wetlands, birds foraged slightly more with increasing cover of Cyperus spp. (r = 0.18, P < 0.001) and Fimbristylis littoralis (r = 0.17, P < 0.01) and decreasing cover of Urochloa mutica (r = -0.15, P < 0.01) and wetland vegetation height (r = -0.22, P < 0.001). Within taro habitat, the behavioral activities of Hawaiian Ducks differed significantly between birds in lo'i and on dikes (F₆,₄₆₈ = 142.8, P < 0.001); birds utilized lo‘i dikes for resting (60%) and maintenance activities (21%), whereas birds entered lo‘i primarily to forage (45%). The activity budget of Hawaiian Ducks was strongly influenced by time of day (F₁₈,₂₇₁₅.₇₈ = 6.4, P < 0.001), and birds spent more time engaged in active behaviors (i.e., foraging, locomotion, and alert) and less time resting during early morning and evening than during late morning and afternoon. While strong seasonal shifts in most behavioral patterns were not detected, males allocated more time to courting (1.1 vs. 0.3%; H1 = 6.92, P = 0.009) and mate-guarding (0.5 vs. <0.1%; H₁ = 9.83, P = 0.002) in managed wetlands between November and March than the remainder of the year. The effects of sex (F₆,₉₆₀ = 6.06, P < 0.001) and social status (F₆,₆₈₂ = 6.69, P < 0.001) on activity budgets were also significant. Females spent more time foraging (18 vs. 12%) and less time in alert, locomotor, and social behaviors than males. Paired birds allocated more time to aggression towards conspecifics, mate-guarding, and courtship, and within taro lo‘i, paired birds foraged more and rested less than unpaired birds. Overall, Hawaiian Duck allocated diurnal activity budgets differently in managed and cultivated wetland habitat at Hanalei NWR, suggesting that both systems may play an important role in fulfilling fundamental daily and seasonal resource requirements. The increased range of activities and foraging tactics used in managed wetlands may indicate the greater habitat diversity (e.g., vegetation structure, patchiness, plant species richness, range of water depths) provided by seasonal wetlands. In general, Hawaiian Duck allocated less time to diurnal foraging than North American Anas, such Mallard and Mottled Duck (A. fulvigula), suggesting that Hawaiian Duck may have lower daily and seasonal energy demands, have access to higher quality diet, or allot more time to nocturnal foraging activities. Also, unlike many North American migratory waterfowl that demonstrate significant behavioral plasticity in adjusting activity budgets to meet seasonal energy demands associated with breeding, molting, wintering, and migration, Hawaiian Duck did not exhibit a strong seasonal shift in most behaviors which may reflect their non-migratory nature and asynchronous life history cycle. Close