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• 2271. [Article] Stable, low-growing plant communities in the western Cascade Mountains : species processes and their implications for rights-of-way management

  The processes that lead to stable, low-growing plant communities and the characteristics of the species that form them are of great interest to rights-of-way (ROW) managers and others wishing to better ...

  Citation × Citation Citation Abstract Copy Title: Stable, low-growing plant communities in the western Cascade Mountains : species processes and their implications for rights-of-way management Author: Nesmith, Jonathan C. B. The processes that lead to stable, low-growing plant communities and the characteristics of the species that form them are of great interest to rights-of-way (ROW) managers and others wishing to better understand plant community resistance to tree invasion on managed landscapes. The use of stable, low-growing plant communities as a mechanism to control tree invasion on ROWs has been widely acknowledged, but little is known about what plant characteristics lead to stable communities or how different treatment methods affect low-growing communities in the Pacific Northwest. The goal of this study was to assess the resistance of stable, low-growing communities to tree invasion on ROW in the Pacific Northwest and to identify common characteristics among the species in these communities that contributed to the formation of stable communities. To address this goal, we investigated 1) the abilities of different species within the low-growing component of the ROW communities to resist invasion by trees and to fill newly created gaps caused by disturbance, 2) the growth patterns and potential for vegetative reproduction of trailing blackberry (Rubus ursinus Cham and Schlecht) and creeping snowberry (Symphoricarpos mollis Nutt.) to understand how different clonal propagation patterns affect spread into unoccupied space and infilling of currently colonized areas, and 3) the effectiveness of several common vegetation control methods for reducing the density of undesirable species and promoting the development of lowgrowing plant communities on ROW. These factors are important processes that determine the stability of a low-growing plant community. This project was conducted at three sites in the western foothills of the Cascade Mountains of Oregon and Washington. Species composition and abundance was measured in roughly 330 2x2 m plots at each site prior to the application of three different treatments aimed at removing tall-growing target species. The plots were measured again two years later to assess changes in species cover. The growth pattern and architecture of trailing blackberry and creeping snowberry was also investigated through the careful excavation of both individual plants and lxi m plots centered in dense thickets of each species. The various treatments used in this study resulted in an average increase in nontarget cover of 65% from 2000 to 2002 while reducing tall target cover by an average of 53%. No difference was found in the change in average nontarget cover or tall target cover among treatments. The effectiveness of the various treatments in reducing target cover varied significantly based on the type of target species being treated. There were no strong differences in resistance among the common lowgrowing species to invasion by tall target species. The range in increase in tall target cover in plots dominated by low-growing species was highly skewed, as tall target cover increased very little in many plots and by as much as 28% in a very few. In the first two years following disturbance, shrubs capable of rapid horizontal expansion through vegetative reproduction, such as trailing blackberry and bracken fern (Pteridium aquilinum), were most successful filling gaps. Their ability to expand rapidly led to their high abundance following disturbance. The successful colonization of gaps by trailing blackberry was a result of its growth pattern, which focused on rapid spread as this species produced new canes annually that grew up to 1.9 m during their first year. This may allow it to be a successful colonizer of gaps. It was also capable of forming dense thickets and averaged 113 stems/m2. The growth pattern of creeping snowberry, which focused more on infilling, may allow it to maintain areas of dense, persistent cover, as it averaged 237 stems/m2 in dense thickets. It was also capable of horizontal spread through the initiation of new ramets along creeping stems. These stems averaged 0.6 m during their first year of growth. Both strategies of growth and spread allowed these shrubs to form thickets of dense vegetation. The use of stable low-growing plant communities as a management tool to reduce tree seedling establishment and growth can have many benefits including reduced costs due to lower tree density and longer periods of time between treatments, increased wildlife habitat, and aesthetic appeal. However, for this management approach to be most successful, one must have an understanding of the plant community where it is being applied, the plant characteristics that will lead to the formation of stable, low-growing communities, and how the different available treatment options will affect the resulting plant community. This study addressed many of these topics to produce a more comprehensive understanding of how stable, low-growing plant communities can be used as a management tool for reducing tree invasion in the Pacific Northwest. The two-year duration of this study, while allowing for many new insights, limited the scope of some of our conclusions. Continued monitoring of these research sites, as has been done in several locations in the northeast United States, would greatly increase the strength of our conclusions. Title: Stable, low-growing plant communities in the western Cascade Mountains : species processes and their implications for rights-of-way management Author: Nesmith, Jonathan C. B. The processes that lead to stable, low-growing plant communities and the characteristics of the species that form them are of great interest to rights-of-way (ROW) managers and others wishing to better understand plant community resistance to tree invasion on managed landscapes. The use of stable, low-growing plant communities as a mechanism to control tree invasion on ROWs has been widely acknowledged, but little is known about what plant characteristics lead to stable communities or how different treatment methods affect low-growing communities in the Pacific Northwest. The goal of this study was to assess the resistance of stable, low-growing communities to tree invasion on ROW in the Pacific Northwest and to identify common characteristics among the species in these communities that contributed to the formation of stable communities. To address this goal, we investigated 1) the abilities of different species within the low-growing component of the ROW communities to resist invasion by trees and to fill newly created gaps caused by disturbance, 2) the growth patterns and potential for vegetative reproduction of trailing blackberry (Rubus ursinus Cham and Schlecht) and creeping snowberry (Symphoricarpos mollis Nutt.) to understand how different clonal propagation patterns affect spread into unoccupied space and infilling of currently colonized areas, and 3) the effectiveness of several common vegetation control methods for reducing the density of undesirable species and promoting the development of lowgrowing plant communities on ROW. These factors are important processes that determine the stability of a low-growing plant community. This project was conducted at three sites in the western foothills of the Cascade Mountains of Oregon and Washington. Species composition and abundance was measured in roughly 330 2x2 m plots at each site prior to the application of three different treatments aimed at removing tall-growing target species. The plots were measured again two years later to assess changes in species cover. The growth pattern and architecture of trailing blackberry and creeping snowberry was also investigated through the careful excavation of both individual plants and lxi m plots centered in dense thickets of each species. The various treatments used in this study resulted in an average increase in nontarget cover of 65% from 2000 to 2002 while reducing tall target cover by an average of 53%. No difference was found in the change in average nontarget cover or tall target cover among treatments. The effectiveness of the various treatments in reducing target cover varied significantly based on the type of target species being treated. There were no strong differences in resistance among the common lowgrowing species to invasion by tall target species. The range in increase in tall target cover in plots dominated by low-growing species was highly skewed, as tall target cover increased very little in many plots and by as much as 28% in a very few. In the first two years following disturbance, shrubs capable of rapid horizontal expansion through vegetative reproduction, such as trailing blackberry and bracken fern (Pteridium aquilinum), were most successful filling gaps. Their ability to expand rapidly led to their high abundance following disturbance. The successful colonization of gaps by trailing blackberry was a result of its growth pattern, which focused on rapid spread as this species produced new canes annually that grew up to 1.9 m during their first year. This may allow it to be a successful colonizer of gaps. It was also capable of forming dense thickets and averaged 113 stems/m2. The growth pattern of creeping snowberry, which focused more on infilling, may allow it to maintain areas of dense, persistent cover, as it averaged 237 stems/m2 in dense thickets. It was also capable of horizontal spread through the initiation of new ramets along creeping stems. These stems averaged 0.6 m during their first year of growth. Both strategies of growth and spread allowed these shrubs to form thickets of dense vegetation. The use of stable low-growing plant communities as a management tool to reduce tree seedling establishment and growth can have many benefits including reduced costs due to lower tree density and longer periods of time between treatments, increased wildlife habitat, and aesthetic appeal. However, for this management approach to be most successful, one must have an understanding of the plant community where it is being applied, the plant characteristics that will lead to the formation of stable, low-growing communities, and how the different available treatment options will affect the resulting plant community. This study addressed many of these topics to produce a more comprehensive understanding of how stable, low-growing plant communities can be used as a management tool for reducing tree invasion in the Pacific Northwest. The two-year duration of this study, while allowing for many new insights, limited the scope of some of our conclusions. Continued monitoring of these research sites, as has been done in several locations in the northeast United States, would greatly increase the strength of our conclusions. Close

• 2272. [Article] Understanding the impact of climate change on snowpack extent and measurement in the Columbia River Basin and nested sub basins

  Shifting climate patterns in the Columbia River basin are affecting snow pack, and, as a result, stream flow throughout the region. In the Oregon Cascades, ever growing populations, and their associated ...

  Citation × Citation Citation Abstract Copy Title: Understanding the impact of climate change on snowpack extent and measurement in the Columbia River Basin and nested sub basins Author: Brown, Aimee Lyn Shifting climate patterns in the Columbia River basin are affecting snow pack, and, as a result, stream flow throughout the region. In the Oregon Cascades, ever growing populations, and their associated activities, place increasing stress on an already over allocated hydrologic system. Political pressures, including the possibility of renegotiation or termination of the Columbia River Treaty between the United States and Canada; societal pressures, including a desire for ecosystem services and fish habitat; and economic pressures, including a need for adequate streamflow for hydropower generation and irrigation, all necessitate a better understanding of current and future snow pack. This work focuses on analyzing the ability of the current snowpack measurement system to represent and capture snowpack in the Columbia River basin and its sub basins under both today’s climate and future climates. In addition, this work develops a more comprehensive knowledge of the impact climate warming will have on snow-covered areas across the region. To determine the efficacy of current snow water equivalence (SWE) measurement sites, the locations and characteristics of sites in the McKenzie River Basin, a sub basin of the Columbia River basin, were considered. SWE was distributed through the basin using the physically based model, SnowModel. SWE values at the four SNOTEL sites in the basin ranged from 0.18-0.37 m at peak SWE. Three of the sites had SWE values greater than 180% of average SWE of the snow covered area. Using elevation, aspect and slope, a 16-node binary regression tree explained controlling variables on SWE at the basin scale. As expected, elevation is the primary determinant in SWE distribution, however, the influence of different parameters shifted throughout the accumulation and ablation seasons. Updated high resolution PRISM precipitation and temperature data are used to map areas within the Columbia River basin and two nested sub basins that are at risk of turning from winter snow dominated precipitation regimes to winter rain dominated under warming scenarios ranging from 1-3°C. Within the Columbia River basin, the Oregon Cascades exhibit the greatest degree of sensitivity to changes in precipitation. Under a 2°C warming scenario, an increase that the International Panel on Climate Change finds highly likely to occur within the next 30 years, 30% of current-day snow covered area in Oregon’s Willamette River Basin will be at risk of turning from snow to rain. The water storage that will be lost if such a change does occur (0.73 km3) is equivalent to more than 8 months worth of water at the current rate of water use in the basin. Data from nine regional stations in the National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS) Cooperative Observer Program were used to validate placement of snow by the model. The conclusions of this work suggest that the placement of snow measurement sites requires refinement and improvement if the measurements are to accurately represent basin wide snowpack today and in the future. Water and natural resource managers will find the results presented here useful for siting future measurement locations that capture and represent SWE during times of interest. While political, societal and economic pressures will only increase, these findings provide early steps for the creation of a more robust system that has the potential to help stakeholders make informed decisions about their water resources, their communities and their needs. Title: Understanding the impact of climate change on snowpack extent and measurement in the Columbia River Basin and nested sub basins Author: Brown, Aimee Lyn Shifting climate patterns in the Columbia River basin are affecting snow pack, and, as a result, stream flow throughout the region. In the Oregon Cascades, ever growing populations, and their associated activities, place increasing stress on an already over allocated hydrologic system. Political pressures, including the possibility of renegotiation or termination of the Columbia River Treaty between the United States and Canada; societal pressures, including a desire for ecosystem services and fish habitat; and economic pressures, including a need for adequate streamflow for hydropower generation and irrigation, all necessitate a better understanding of current and future snow pack. This work focuses on analyzing the ability of the current snowpack measurement system to represent and capture snowpack in the Columbia River basin and its sub basins under both today’s climate and future climates. In addition, this work develops a more comprehensive knowledge of the impact climate warming will have on snow-covered areas across the region. To determine the efficacy of current snow water equivalence (SWE) measurement sites, the locations and characteristics of sites in the McKenzie River Basin, a sub basin of the Columbia River basin, were considered. SWE was distributed through the basin using the physically based model, SnowModel. SWE values at the four SNOTEL sites in the basin ranged from 0.18-0.37 m at peak SWE. Three of the sites had SWE values greater than 180% of average SWE of the snow covered area. Using elevation, aspect and slope, a 16-node binary regression tree explained controlling variables on SWE at the basin scale. As expected, elevation is the primary determinant in SWE distribution, however, the influence of different parameters shifted throughout the accumulation and ablation seasons. Updated high resolution PRISM precipitation and temperature data are used to map areas within the Columbia River basin and two nested sub basins that are at risk of turning from winter snow dominated precipitation regimes to winter rain dominated under warming scenarios ranging from 1-3°C. Within the Columbia River basin, the Oregon Cascades exhibit the greatest degree of sensitivity to changes in precipitation. Under a 2°C warming scenario, an increase that the International Panel on Climate Change finds highly likely to occur within the next 30 years, 30% of current-day snow covered area in Oregon’s Willamette River Basin will be at risk of turning from snow to rain. The water storage that will be lost if such a change does occur (0.73 km3) is equivalent to more than 8 months worth of water at the current rate of water use in the basin. Data from nine regional stations in the National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS) Cooperative Observer Program were used to validate placement of snow by the model. The conclusions of this work suggest that the placement of snow measurement sites requires refinement and improvement if the measurements are to accurately represent basin wide snowpack today and in the future. Water and natural resource managers will find the results presented here useful for siting future measurement locations that capture and represent SWE during times of interest. While political, societal and economic pressures will only increase, these findings provide early steps for the creation of a more robust system that has the potential to help stakeholders make informed decisions about their water resources, their communities and their needs. Close

• 2273. [Article] Use of MIKE SHE for estimation of evapotranspiration in the Sprague River Basin

  MIKE SHE is a fully distributed, physically-based hydrologic model that can simulate water movement over and under the Earth's surface. Evapotranspiration (ET) is one of the components of this model. MIKE ...

  Citation × Citation Citation Abstract Copy Title: Use of MIKE SHE for estimation of evapotranspiration in the Sprague River Basin Author: Shakya, Suva R. MIKE SHE is a fully distributed, physically-based hydrologic model that can simulate water movement over and under the Earth's surface. Evapotranspiration (ET) is one of the components of this model. MIKE SHE uses a modification of the Kristensen -Jensen (1975) method to calculate actual ET. This method is based on addition of the three evapotranspiration components – interception storage, transpiration by the plant and evaporation from the soil surface, to compute total actual evapotranspiration. The validity of the Kristensen-Jensen method has been tested on an arid region within the Sprague River subbasin of the Upper Klamath basin in southern Oregon. The model was setup on a 1,000 m by 1,000 m flat surface as a one-dimensional grid cell. There are sixteen computation layers which make three soil profile layers with varying soil properties. Meteorological data from the Pacific Northwest Cooperative Agricultural Weather Network (AgriMet) were used to setup the model. Soil physical properties were taken from the Soil Survey Geographic (SSURGO) database of the Natural Resources Conservation Service (NRCS). Values of the van Genuchten parameters for soil water retention and hydraulic conductivity as a function of soil texture from Carsel and Parrish (1988) were applied. Wetland vegetation such as duckweed and cattail, natural vegetation such as big sagebrush, ponderosa pine and juniper, and agricultural crops such as grass pasture and maize were used to test MIKE SHE evapotranspiration simulation. The length of growth stage, crop coefficient, leaf area index (LAI) and root depth values were taken from the literature. Actual crop ET rates were calculated based on AgriMet reference ET which uses the Kimberly Penman (Wright, 1982) method. The alfalfa reference ET was converted to a grass reference by multiplying by a factor of 0.833 (Jensen et al., 1990). The single crop coefficient method was used and soil stress was accounted for using the FAO 56 method (Allen et al, 1998). Simulated irrigation was applied to maize and grass to keep the root zone soil moisture close to field capacity. Crop ET rates from the MIKE SHE simulation were then compared to the AgriMet based ET rates, resulting in a comparison of Kristensen-Jensen method against the Kimberly Penman method. Both the Kristensen-Jensen and AgriMet simulation scenarios were driven by the same reference ET and the same FAO 56 basal crop coefficient. Differences are therefore a function of different methods for dealing with soil moisture stress. Results indicate that the MIKE SHE simulated evapotranspiration corresponds to the Kimberly Penman method for the duckweed and cattail wetlands species with resulting Nash and Sutcliffe (NS) efficiencies of 0.97 and 1.00, respectively. The big sagebrush, juniper, and ponderosa pine species required a soil stress correction factor for the crop coefficients and the results yielded NS efficiency values of 0.14, 0.59 and 0.68, respectively. Irrigation was automatically turned on for maize at a 20 percent soil moisture deficit to minimize the effects of water stress and the resulting NS efficiency was 0.85. For pasture, an irrigation based on average monthly water deficit for pasture in Klamath was used (Cuenca et al.,1992). This resulted in a NS efficiency of 0.77. Each crop requires unique treatment within the model. Required vegetation parameters such as crop coefficient and LAI, climatic factors such as reference ET, and soil hydraulic properties need to be based on local conditions to the extent possible. It should be noted that the MIKE SHE simulations were run in a one-dimensional mode which precluded accounting for spatial variability or lateral flow of surface or groundwater. The simulation results indicate that converting the study area into a well irrigated pasture would require application of substantial amounts of irrigation water by sprinkler or flooding. Wetlands would require even more water to flood the land, but would be well suited for development of regional habitat. Big sagebrush, juniper and ponderosa pine survive under natural conditions but experience considerable plant stress brought on by soil water deficits which limit plant production below the maximum possible growth. Title: Use of MIKE SHE for estimation of evapotranspiration in the Sprague River Basin Author: Shakya, Suva R. MIKE SHE is a fully distributed, physically-based hydrologic model that can simulate water movement over and under the Earth's surface. Evapotranspiration (ET) is one of the components of this model. MIKE SHE uses a modification of the Kristensen -Jensen (1975) method to calculate actual ET. This method is based on addition of the three evapotranspiration components – interception storage, transpiration by the plant and evaporation from the soil surface, to compute total actual evapotranspiration. The validity of the Kristensen-Jensen method has been tested on an arid region within the Sprague River subbasin of the Upper Klamath basin in southern Oregon. The model was setup on a 1,000 m by 1,000 m flat surface as a one-dimensional grid cell. There are sixteen computation layers which make three soil profile layers with varying soil properties. Meteorological data from the Pacific Northwest Cooperative Agricultural Weather Network (AgriMet) were used to setup the model. Soil physical properties were taken from the Soil Survey Geographic (SSURGO) database of the Natural Resources Conservation Service (NRCS). Values of the van Genuchten parameters for soil water retention and hydraulic conductivity as a function of soil texture from Carsel and Parrish (1988) were applied. Wetland vegetation such as duckweed and cattail, natural vegetation such as big sagebrush, ponderosa pine and juniper, and agricultural crops such as grass pasture and maize were used to test MIKE SHE evapotranspiration simulation. The length of growth stage, crop coefficient, leaf area index (LAI) and root depth values were taken from the literature. Actual crop ET rates were calculated based on AgriMet reference ET which uses the Kimberly Penman (Wright, 1982) method. The alfalfa reference ET was converted to a grass reference by multiplying by a factor of 0.833 (Jensen et al., 1990). The single crop coefficient method was used and soil stress was accounted for using the FAO 56 method (Allen et al, 1998). Simulated irrigation was applied to maize and grass to keep the root zone soil moisture close to field capacity. Crop ET rates from the MIKE SHE simulation were then compared to the AgriMet based ET rates, resulting in a comparison of Kristensen-Jensen method against the Kimberly Penman method. Both the Kristensen-Jensen and AgriMet simulation scenarios were driven by the same reference ET and the same FAO 56 basal crop coefficient. Differences are therefore a function of different methods for dealing with soil moisture stress. Results indicate that the MIKE SHE simulated evapotranspiration corresponds to the Kimberly Penman method for the duckweed and cattail wetlands species with resulting Nash and Sutcliffe (NS) efficiencies of 0.97 and 1.00, respectively. The big sagebrush, juniper, and ponderosa pine species required a soil stress correction factor for the crop coefficients and the results yielded NS efficiency values of 0.14, 0.59 and 0.68, respectively. Irrigation was automatically turned on for maize at a 20 percent soil moisture deficit to minimize the effects of water stress and the resulting NS efficiency was 0.85. For pasture, an irrigation based on average monthly water deficit for pasture in Klamath was used (Cuenca et al.,1992). This resulted in a NS efficiency of 0.77. Each crop requires unique treatment within the model. Required vegetation parameters such as crop coefficient and LAI, climatic factors such as reference ET, and soil hydraulic properties need to be based on local conditions to the extent possible. It should be noted that the MIKE SHE simulations were run in a one-dimensional mode which precluded accounting for spatial variability or lateral flow of surface or groundwater. The simulation results indicate that converting the study area into a well irrigated pasture would require application of substantial amounts of irrigation water by sprinkler or flooding. Wetlands would require even more water to flood the land, but would be well suited for development of regional habitat. Big sagebrush, juniper and ponderosa pine survive under natural conditions but experience considerable plant stress brought on by soil water deficits which limit plant production below the maximum possible growth. Close

• 2274. [Article] Ecological study of aquatic myxobacteria in a woodland stream

  Most studies of bacteria in water have concerned public health; little attention has been given to organisms which are indigenous to the aquatic environment. Myxobacteria are known to occur in soil, in ...

  Citation × Citation Citation Abstract Copy Title: Ecological study of aquatic myxobacteria in a woodland stream Author: Carlson, René Virginia Most studies of bacteria in water have concerned public health; little attention has been given to organisms which are indigenous to the aquatic environment. Myxobacteria are known to occur in soil, in the marine environment, and several have been studied in relation to diseases of salmonid fishes. However, little information is available regarding the role of myxobacteria in the freshwater environment. The major purpose of this research was to obtain data on the occurrence, distribution, and activities of aquatic myxobacteria in a woodland stream. As a preliminary step for studying the ecology of myxobacteria in the freshwater stream, a culture medium and procedure were developed to provide a means for isolation and enumeration of these organisms. Enumeration of myxobacteria was based on the morphology of the colonies growing on the dilute nutrient medium, cytophaga peptonized milk agar (CPM). The low nutrient concentration of this medium favored spreading of the myxobacterial colony and the production of rhizoid edge patterns which are typical of myxobacteria and distinguishable from eubacterial colonies. The enumeration method was used to obtain data on the occurrence and distribution of myxobacteria as compared to the total bacteria population in Berry Creek. Results of the ecological study conducted over a two and a half year period indicate that myxobacteria are present in this aquatic environment all during the year with highest levels obtained in the fall (October and November) and lowest levels during the summer (July and August). Seasonal variations also occurred in the types of myxobacteria comprising the population of the stream. It is interesting to note that peaks in the myxobacterial and the total bacterial populations occurred in advance of the peak in flow rate. Water temperature and flow rate did not seem to influence the population levels as might be expected if the myxobacteria were transient members of the microbial flora. Additional surveys have shown that the myxobacteria are widespread in fresh water; they have been found in abundance in bottom sediments and surface films as well as in the flowing waters. Myxobacteria also appear to be well adapted to the aquatic environment. It was shown that they are able to utilize the dilute nutrients present in water for their growth. In an attempt to determine the possible role myxobacteria play in the aquatic environment, the predominant myxobacterial types were isolated and studied morphologically and biochemically. All the organisms studied corresponded to the classical definition of myxobacterial cells: gram negative, slender, weakly refractile rodshaped bacteria which exhibit gliding motility. Colony morphology of these myxobacteria plated on CPM has been studied in detail and found to be a constant characteristic of the particular type of myxobacteria isolate. Photographs of several of the predominant forms present in the stream samples illustrate the distinguishable morphology of the myxobacterial colonies. Six morphological groups have been arbitrarily designated on the basis of colony morphology; these morphological groups also show similarities in their biochemical capabilities. Biochemical studies on the myxobacterial isolates indicated that most of the strains were able to utilize simple carbohydrates. All of the isolates were capable of degrading various macromolecules, such as chitin, starch, aesculin, caesin, gelatin, and carboxy methyl cellulose. One of the isolates obtained was strictly proteolytic. The ability to hydrolyze macromolecules appears to be characteristic of aquatic isolates as well as of other myxobacteria. One myxobacterium isolated was believed to be intimately associated with the sheathed bacterium, Sphaerotilus natans. The latter organism was abundant in the sucrose and urea enriched section of Berry Creek. This myxobacterium could not utilize sucrose or urea and occurred only in the enriched section of the stream when Sphaerotilus was present. The fish pathogen, Chondrococcus columnaris was also isolated from Berry Creek water. This myxobacterium can be distinguished from the other aquatic myxobacteria on the basis of its unique colony morphology. This strain of C. columnaris proved to be one of the common serological types found in the Pacific Northwest. Based on the results obtained thus far, it is possible to speculate on the role of myxobacteria in the freshwater environment. All of the myxobacteria isolated in this study are capable of decomposing complex materials, it seems likely therefore, that these organisms may be active in the decomposition of such complex organic compounds, including the remains of other bacterial cells, which are present in the aquatic habitat. Since the isolates studied are also able to utilize the nutrients present at low levels in the stream water, these myxobacteria are not dependent on macromolecular substrates. Myxobacteria with these abilities are apparently well adapted to the aquatic environment. Title: Ecological study of aquatic myxobacteria in a woodland stream Author: Carlson, René Virginia Most studies of bacteria in water have concerned public health; little attention has been given to organisms which are indigenous to the aquatic environment. Myxobacteria are known to occur in soil, in the marine environment, and several have been studied in relation to diseases of salmonid fishes. However, little information is available regarding the role of myxobacteria in the freshwater environment. The major purpose of this research was to obtain data on the occurrence, distribution, and activities of aquatic myxobacteria in a woodland stream. As a preliminary step for studying the ecology of myxobacteria in the freshwater stream, a culture medium and procedure were developed to provide a means for isolation and enumeration of these organisms. Enumeration of myxobacteria was based on the morphology of the colonies growing on the dilute nutrient medium, cytophaga peptonized milk agar (CPM). The low nutrient concentration of this medium favored spreading of the myxobacterial colony and the production of rhizoid edge patterns which are typical of myxobacteria and distinguishable from eubacterial colonies. The enumeration method was used to obtain data on the occurrence and distribution of myxobacteria as compared to the total bacteria population in Berry Creek. Results of the ecological study conducted over a two and a half year period indicate that myxobacteria are present in this aquatic environment all during the year with highest levels obtained in the fall (October and November) and lowest levels during the summer (July and August). Seasonal variations also occurred in the types of myxobacteria comprising the population of the stream. It is interesting to note that peaks in the myxobacterial and the total bacterial populations occurred in advance of the peak in flow rate. Water temperature and flow rate did not seem to influence the population levels as might be expected if the myxobacteria were transient members of the microbial flora. Additional surveys have shown that the myxobacteria are widespread in fresh water; they have been found in abundance in bottom sediments and surface films as well as in the flowing waters. Myxobacteria also appear to be well adapted to the aquatic environment. It was shown that they are able to utilize the dilute nutrients present in water for their growth. In an attempt to determine the possible role myxobacteria play in the aquatic environment, the predominant myxobacterial types were isolated and studied morphologically and biochemically. All the organisms studied corresponded to the classical definition of myxobacterial cells: gram negative, slender, weakly refractile rodshaped bacteria which exhibit gliding motility. Colony morphology of these myxobacteria plated on CPM has been studied in detail and found to be a constant characteristic of the particular type of myxobacteria isolate. Photographs of several of the predominant forms present in the stream samples illustrate the distinguishable morphology of the myxobacterial colonies. Six morphological groups have been arbitrarily designated on the basis of colony morphology; these morphological groups also show similarities in their biochemical capabilities. Biochemical studies on the myxobacterial isolates indicated that most of the strains were able to utilize simple carbohydrates. All of the isolates were capable of degrading various macromolecules, such as chitin, starch, aesculin, caesin, gelatin, and carboxy methyl cellulose. One of the isolates obtained was strictly proteolytic. The ability to hydrolyze macromolecules appears to be characteristic of aquatic isolates as well as of other myxobacteria. One myxobacterium isolated was believed to be intimately associated with the sheathed bacterium, Sphaerotilus natans. The latter organism was abundant in the sucrose and urea enriched section of Berry Creek. This myxobacterium could not utilize sucrose or urea and occurred only in the enriched section of the stream when Sphaerotilus was present. The fish pathogen, Chondrococcus columnaris was also isolated from Berry Creek water. This myxobacterium can be distinguished from the other aquatic myxobacteria on the basis of its unique colony morphology. This strain of C. columnaris proved to be one of the common serological types found in the Pacific Northwest. Based on the results obtained thus far, it is possible to speculate on the role of myxobacteria in the freshwater environment. All of the myxobacteria isolated in this study are capable of decomposing complex materials, it seems likely therefore, that these organisms may be active in the decomposition of such complex organic compounds, including the remains of other bacterial cells, which are present in the aquatic habitat. Since the isolates studied are also able to utilize the nutrients present at low levels in the stream water, these myxobacteria are not dependent on macromolecular substrates. Myxobacteria with these abilities are apparently well adapted to the aquatic environment. Close

• 2275. [Article] Assessment of the potential for conflict between existing ocean space use and renewable energy development off the coast of Oregon

  Oregon's ocean waters are a potential source of wind, wave, and tidal energy; of interest to renewable energy entrepreneurs and to the U.S. government as it seeks to bolster energy security. In order to ...

  Citation × Citation Citation Abstract Copy Title: Assessment of the potential for conflict between existing ocean space use and renewable energy development off the coast of Oregon Author: Sullivan, Colleen M. (Colleen Marie) Oregon's ocean waters are a potential source of wind, wave, and tidal energy; of interest to renewable energy entrepreneurs and to the U.S. government as it seeks to bolster energy security. In order to install technology to capture this energy, however, it may be necessary to mitigate conflict with existing ocean space users. The objective of this research was to construct a conflict analysis model in a GIS to answer the following research questions: (1) Within the study area off the coast of Oregon, where are stakeholders currently using ocean space and how many uses overlap? (2) To what extent might existing ocean space use present potential for conflict with renewable energy development? (3) How do various types of uncertainty affect analysis results? (4) What are the implications of these findings for ecosystem based management of the ocean? All available spatial information on ocean space usage by commercial fishing, commercial non-fishing, recreational, Native American, and scientific communities was gathered. Stakeholder outreach with these communities was used to vet the collected data and allow each to contribute knowledge not previously available through GIS data clearinghouses maintained by government or interest groups. The resulting data were used as inputs to a conflict visualization model written in Python and imported to an ArcGIS tool. Results showed extensive coverage and overlap of existing ocean space uses; specifically that 99.7% of the 1-nm² grid cells of the study area are occupied by at least 6 different categories of ocean space use. The six uses with the greatest coverage were: Fishing – Trolling, Habitat, Military, Fishing - Closure Areas, Protected, and Marine Transportation - Low Intensity. An uncertainty analysis was also completed to illustrate the margin for error and therefore the necessity of appropriate stakeholder outreach during the renewable energy siting process, as opposed to relying only on a GIS. Ranking of each category by its potential for conflict with renewable energy development demonstrated which areas of the ocean may be particularly contentious. Because rankings are subjective, a tool was created to allow users to input their own rankings. For the purpose of this report, default rankings were assigned to each as justified by the literature. Results under these assumptions showed that space use and potential for conflict were highest between the coast and approximately 30 nm at sea. This is likely because certain space use is limited by depth (e.g., recreational use); there is increased shipping density as vessels approach and depart major ports; and increased fuel costs associated with traveling further from shore. Two potential applications of model results were demonstrated. First, comparison with existing wave energy permit sites highlighted relative potential for conflict among the sites and the input data detailed the specific uses present. Second, comparison with areas determined most suitable for development by the wave energy industry illustrated that areas of high suitability often also had high rankings for potential for conflict. It appeared that the factors that determined development suitability were often the same factors that drew current ocean space users to those locations. Current support at the state, regional and federal level under the National Ocean Policy for the use of marine spatial planning as a tool to implement ecosystem based management of the oceans requires that tools such as the one developed in this research are used, to ensure that all components of the marine ecosystem are considered prior to implementation of a management plan. The addition of renewable energy to the current social landscape of the ocean will reduce the resource base for many categories of ocean space use. Model results demonstrated that mitigation of conflict between development and existing space use is not merely a best practice supported by current policy, but a necessity. Results presented a visualization of the social landscape of the ocean that could help managers determine which stakeholders to engage during the initial stage of choosing a site for development. Title: Assessment of the potential for conflict between existing ocean space use and renewable energy development off the coast of Oregon Author: Sullivan, Colleen M. (Colleen Marie) Oregon's ocean waters are a potential source of wind, wave, and tidal energy; of interest to renewable energy entrepreneurs and to the U.S. government as it seeks to bolster energy security. In order to install technology to capture this energy, however, it may be necessary to mitigate conflict with existing ocean space users. The objective of this research was to construct a conflict analysis model in a GIS to answer the following research questions: (1) Within the study area off the coast of Oregon, where are stakeholders currently using ocean space and how many uses overlap? (2) To what extent might existing ocean space use present potential for conflict with renewable energy development? (3) How do various types of uncertainty affect analysis results? (4) What are the implications of these findings for ecosystem based management of the ocean? All available spatial information on ocean space usage by commercial fishing, commercial non-fishing, recreational, Native American, and scientific communities was gathered. Stakeholder outreach with these communities was used to vet the collected data and allow each to contribute knowledge not previously available through GIS data clearinghouses maintained by government or interest groups. The resulting data were used as inputs to a conflict visualization model written in Python and imported to an ArcGIS tool. Results showed extensive coverage and overlap of existing ocean space uses; specifically that 99.7% of the 1-nm² grid cells of the study area are occupied by at least 6 different categories of ocean space use. The six uses with the greatest coverage were: Fishing – Trolling, Habitat, Military, Fishing - Closure Areas, Protected, and Marine Transportation - Low Intensity. An uncertainty analysis was also completed to illustrate the margin for error and therefore the necessity of appropriate stakeholder outreach during the renewable energy siting process, as opposed to relying only on a GIS. Ranking of each category by its potential for conflict with renewable energy development demonstrated which areas of the ocean may be particularly contentious. Because rankings are subjective, a tool was created to allow users to input their own rankings. For the purpose of this report, default rankings were assigned to each as justified by the literature. Results under these assumptions showed that space use and potential for conflict were highest between the coast and approximately 30 nm at sea. This is likely because certain space use is limited by depth (e.g., recreational use); there is increased shipping density as vessels approach and depart major ports; and increased fuel costs associated with traveling further from shore. Two potential applications of model results were demonstrated. First, comparison with existing wave energy permit sites highlighted relative potential for conflict among the sites and the input data detailed the specific uses present. Second, comparison with areas determined most suitable for development by the wave energy industry illustrated that areas of high suitability often also had high rankings for potential for conflict. It appeared that the factors that determined development suitability were often the same factors that drew current ocean space users to those locations. Current support at the state, regional and federal level under the National Ocean Policy for the use of marine spatial planning as a tool to implement ecosystem based management of the oceans requires that tools such as the one developed in this research are used, to ensure that all components of the marine ecosystem are considered prior to implementation of a management plan. The addition of renewable energy to the current social landscape of the ocean will reduce the resource base for many categories of ocean space use. Model results demonstrated that mitigation of conflict between development and existing space use is not merely a best practice supported by current policy, but a necessity. Results presented a visualization of the social landscape of the ocean that could help managers determine which stakeholders to engage during the initial stage of choosing a site for development. Close

• 2276. [Article] Metabolic adjustment to temperature in Strongylocentrotus purpuratus (Stimpson)

  The metabolism of Strongylocentrotus purpuratus (Stimpson) was investigated at several levels of urchin organization. Some experiments were performed with tissues from recently collected (acclimatized) ...

  Citation × Citation Citation Abstract Copy Title: Metabolic adjustment to temperature in Strongylocentrotus purpuratus (Stimpson) Author: Ulbricht, Richard Jules The metabolism of Strongylocentrotus purpuratus (Stimpson) was investigated at several levels of urchin organization. Some experiments were performed with tissues from recently collected (acclimatized) urchins, Other experiments were performed with tissues from urchins held at one of two temperatures (acclimated) for 30 days. Body-component oxygen consumption was measured for bodywall, gut, testis, and ovary slices from seasonally acclimatized and temperature-acclimated urchins. Metabolic rates of testis and ovary underwent seasonal shifts appearing to compensate for changes in habitat temperature -- i. e., higher and lower rates during cold and warm periods, respectively. Rates of body wall and gut underwent seasonal shifts in a direction opposite those of testis and ovary -- i. e. , inverse compensation. This gonadal-nonreproductive difference was observed less conclusively with temperature-acclimated urchins. Compensatory shifts occurred with testis. Equivocal shifts occurred with body wall, gut, and ovary. Inverse compensation of metabolic rate resulted when oxygen-consumption measurements were repeated with gut slices and homogenates from temperature-acclimated urchins. Radiotracers glucose-1-¹⁴C, glucose-6-¹⁴C, and acetate- 1-¹⁴C -- were incubated with gut, testis, and ovary homogenates from temperature-acclimated urchins. Cold acclimation caused higher CO₂ and lower lipid activities in the testis. Conversely, warm acclimation caused higher CO₂ and lower lipid activities in the gut. Conversion of glucose to CO₂ was greater in gut than in testis. Conversion of acetate to lipid was generally greater in testis than in gut. Phosphogluconate oxidation and lipid synthesis relative to glycolysis and oxidation, respectively, increased in the testis following warm acclimation. Conversely, glycolysis and oxidation relative to phosphogluconate oxidation and lipid synthesis, respectively, increased in the gut following warm acclimation. Cold acclimation resulted in higher levels of glycogenesis for testis and ovary but in equivocal differences for gut. Cytochrome c oxidase activity was determined in gut, testis, and ovary extracts from seasonally acclimatized and temperatureacclimated urchins. Changes in enzyme activity paralleled those in the oxygen-consumption and radiotracer results. Gut activity was highest in September, whereas testis and ovary activities were highest in December and March, respectively. Gut activity was higher following warm acclimation, but testis and ovary activities were higher following cold acclimation. Glucose 6-phosphate dehydrogenase (G6PDH) activity was determined in gut, testis, and ovary extracts from temperature-acclimated urchins. Changes in G6PDH activity were the reverse of those in the oxygen-consumption, radiotracer, and cytochrome c oxidase results, suggesting that changes in the effectiveness with which glycolysis and phosphogluconate oxidation compete for the common substrate, glucose 6-phosphate (G6P), may compensate for each other. Warm acclimation generally increased gonadal G6PDH activity but failed to alter gut activity. Gonadal G6PDH activity was generally much higher than was that of the gut. The apparent G6PDH-G6P affinity for gut, testis, and ovary was increased following cold acclimation. Body-component weights were determined from the urchins used in the metabolic rate-season studies. Gonadal ash-free dry weights expressed as a percentage of the total were maximal in the fall and minimal in the spring, whereas those of the body wall were maximal in the spring and minimal in the fall. Seasonal changes in the gut were negligible by comparison. The above temperature-induced changes in urchin metabolism are discussed relative to temperature-induced changes in whole-urchin metabolism and to situations confronting intertidal populations of urchins. Gonadal catabolism appears maximal in the winter or spring and minimal in the fall, whereas gonadal anabolism appears maximal in the fall and minimal in the spring. Nonreproductive catabolism appears maximal in the fall and minimal in the winter, whereas nonreproductive anabolism appears maximal in the spring and minimal in the fall. Title: Metabolic adjustment to temperature in Strongylocentrotus purpuratus (Stimpson) Author: Ulbricht, Richard Jules The metabolism of Strongylocentrotus purpuratus (Stimpson) was investigated at several levels of urchin organization. Some experiments were performed with tissues from recently collected (acclimatized) urchins, Other experiments were performed with tissues from urchins held at one of two temperatures (acclimated) for 30 days. Body-component oxygen consumption was measured for bodywall, gut, testis, and ovary slices from seasonally acclimatized and temperature-acclimated urchins. Metabolic rates of testis and ovary underwent seasonal shifts appearing to compensate for changes in habitat temperature -- i. e., higher and lower rates during cold and warm periods, respectively. Rates of body wall and gut underwent seasonal shifts in a direction opposite those of testis and ovary -- i. e. , inverse compensation. This gonadal-nonreproductive difference was observed less conclusively with temperature-acclimated urchins. Compensatory shifts occurred with testis. Equivocal shifts occurred with body wall, gut, and ovary. Inverse compensation of metabolic rate resulted when oxygen-consumption measurements were repeated with gut slices and homogenates from temperature-acclimated urchins. Radiotracers glucose-1-¹⁴C, glucose-6-¹⁴C, and acetate- 1-¹⁴C -- were incubated with gut, testis, and ovary homogenates from temperature-acclimated urchins. Cold acclimation caused higher CO₂ and lower lipid activities in the testis. Conversely, warm acclimation caused higher CO₂ and lower lipid activities in the gut. Conversion of glucose to CO₂ was greater in gut than in testis. Conversion of acetate to lipid was generally greater in testis than in gut. Phosphogluconate oxidation and lipid synthesis relative to glycolysis and oxidation, respectively, increased in the testis following warm acclimation. Conversely, glycolysis and oxidation relative to phosphogluconate oxidation and lipid synthesis, respectively, increased in the gut following warm acclimation. Cold acclimation resulted in higher levels of glycogenesis for testis and ovary but in equivocal differences for gut. Cytochrome c oxidase activity was determined in gut, testis, and ovary extracts from seasonally acclimatized and temperatureacclimated urchins. Changes in enzyme activity paralleled those in the oxygen-consumption and radiotracer results. Gut activity was highest in September, whereas testis and ovary activities were highest in December and March, respectively. Gut activity was higher following warm acclimation, but testis and ovary activities were higher following cold acclimation. Glucose 6-phosphate dehydrogenase (G6PDH) activity was determined in gut, testis, and ovary extracts from temperature-acclimated urchins. Changes in G6PDH activity were the reverse of those in the oxygen-consumption, radiotracer, and cytochrome c oxidase results, suggesting that changes in the effectiveness with which glycolysis and phosphogluconate oxidation compete for the common substrate, glucose 6-phosphate (G6P), may compensate for each other. Warm acclimation generally increased gonadal G6PDH activity but failed to alter gut activity. Gonadal G6PDH activity was generally much higher than was that of the gut. The apparent G6PDH-G6P affinity for gut, testis, and ovary was increased following cold acclimation. Body-component weights were determined from the urchins used in the metabolic rate-season studies. Gonadal ash-free dry weights expressed as a percentage of the total were maximal in the fall and minimal in the spring, whereas those of the body wall were maximal in the spring and minimal in the fall. Seasonal changes in the gut were negligible by comparison. The above temperature-induced changes in urchin metabolism are discussed relative to temperature-induced changes in whole-urchin metabolism and to situations confronting intertidal populations of urchins. Gonadal catabolism appears maximal in the winter or spring and minimal in the fall, whereas gonadal anabolism appears maximal in the fall and minimal in the spring. Nonreproductive catabolism appears maximal in the fall and minimal in the winter, whereas nonreproductive anabolism appears maximal in the spring and minimal in the fall. Close

• 2277. [Article] Seasonal life history of Oncorhynchus mykiss in the South Fork John Day River Basin, Oregon

  Understanding seasonal changes in growth, survival, and movement rates is crucial to salmonid management. These life history characteristics provide a context for evaluation of management actions. We evaluated ...

  Citation × Citation Citation Abstract Copy Title: Seasonal life history of Oncorhynchus mykiss in the South Fork John Day River Basin, Oregon Author: Tattam, Ian A. Understanding seasonal changes in growth, survival, and movement rates is crucial to salmonid management. These life history characteristics provide a context for evaluation of management actions. We evaluated the life history of individually marked Oncorhynchus mykiss gairdneri in the South Fork John Day River basin in Northeastern Oregon. This thesis focuses on Murderers and Black Canyon creeks, two tributaries to the South Fork John Day. These are semi-arid, mid elevation basins with naturally reproducing populations of summer steelhead and redband trout (both O. mykiss). Summer steelhead populations in this basin have declined from historic abundances, and are protected under the Endangered Species Act. In Chapter 2, we evaluate life history variation in Murderers Creek during four consecutive seasons. Growth rate varied significantly with season (F[subscript 3,88] = 62.56, P < 0.0001), with most growth occurring during spring. Location and season interacted F[subscript 6,88] = 4.45, P < 0.001) to influence individual growth rates. As a result, regions of high growth potential shifted up and down-stream seasonally. However, we found low rates of O. mykiss movement (<3%) in Murderers Creek during summer, suggesting that individuals did not track resource availability at a large scale. Apparent survival rate varied among reaches, but was consistently higher in the upstream most reach compared to the two lowermost reaches. Survival rates were similar between summer and fall, indicating that declining fall temperatures did not increase mortality. A shift in population distribution occured during fall (September through December), as some O. mykiss emigrated from tributaries into the mainstem South Fork John Day River. In Chapter 3, we investigate differences in fall life history between and within tributaries. A significantly greater proportion of O. mykiss emigrated from Murderers Creek compared to Black Canyon Creek during two consecutive years (P < 0.001 for both years). There were no significant differences in proportion of emigrants between years within either stream (P > 0.10 for both streams). In Murderers Creek, odds of emigration were related to stream reach of summer residence. Odds of fall emigration were also significantly and positively related to body length in fall and growth rate during summer. This suggests that competitive dominants volitionally emigrated from Murderers Creek during fall. After emigration, O. mykiss dispersed primarily further downstream into the Mainstem John Day River. Radio-telemetry indicated that the majority of fall emigrants occupied a < 6 km section of the Mainstem John Day River. Fall emigrants had growth rates during their winter niche shift that were significantly (P < 0.001) higher than those of individuals remaining in tributaries. This study underscores the need to monitor during all seasons to accurately characterize habitat quality. Life history patterns are an important population response to environmental change. This thesis provides an ecological context for monitoring recovery of O. mykiss populations in the South Fork John Day River basin. Title: Seasonal life history of Oncorhynchus mykiss in the South Fork John Day River Basin, Oregon Author: Tattam, Ian A. Understanding seasonal changes in growth, survival, and movement rates is crucial to salmonid management. These life history characteristics provide a context for evaluation of management actions. We evaluated the life history of individually marked Oncorhynchus mykiss gairdneri in the South Fork John Day River basin in Northeastern Oregon. This thesis focuses on Murderers and Black Canyon creeks, two tributaries to the South Fork John Day. These are semi-arid, mid elevation basins with naturally reproducing populations of summer steelhead and redband trout (both O. mykiss). Summer steelhead populations in this basin have declined from historic abundances, and are protected under the Endangered Species Act. In Chapter 2, we evaluate life history variation in Murderers Creek during four consecutive seasons. Growth rate varied significantly with season (F[subscript 3,88] = 62.56, P < 0.0001), with most growth occurring during spring. Location and season interacted F[subscript 6,88] = 4.45, P < 0.001) to influence individual growth rates. As a result, regions of high growth potential shifted up and down-stream seasonally. However, we found low rates of O. mykiss movement (<3%) in Murderers Creek during summer, suggesting that individuals did not track resource availability at a large scale. Apparent survival rate varied among reaches, but was consistently higher in the upstream most reach compared to the two lowermost reaches. Survival rates were similar between summer and fall, indicating that declining fall temperatures did not increase mortality. A shift in population distribution occured during fall (September through December), as some O. mykiss emigrated from tributaries into the mainstem South Fork John Day River. In Chapter 3, we investigate differences in fall life history between and within tributaries. A significantly greater proportion of O. mykiss emigrated from Murderers Creek compared to Black Canyon Creek during two consecutive years (P < 0.001 for both years). There were no significant differences in proportion of emigrants between years within either stream (P > 0.10 for both streams). In Murderers Creek, odds of emigration were related to stream reach of summer residence. Odds of fall emigration were also significantly and positively related to body length in fall and growth rate during summer. This suggests that competitive dominants volitionally emigrated from Murderers Creek during fall. After emigration, O. mykiss dispersed primarily further downstream into the Mainstem John Day River. Radio-telemetry indicated that the majority of fall emigrants occupied a < 6 km section of the Mainstem John Day River. Fall emigrants had growth rates during their winter niche shift that were significantly (P < 0.001) higher than those of individuals remaining in tributaries. This study underscores the need to monitor during all seasons to accurately characterize habitat quality. Life history patterns are an important population response to environmental change. This thesis provides an ecological context for monitoring recovery of O. mykiss populations in the South Fork John Day River basin. Close

• 2278. [Article] An investigation of the utilization of four study areas in Yaquina Bay, Oregon, by hatchery and wild juvenile salmonids

  Results of a study of spatial and temporal utilization of a tidal river estuary by hatchery and wild juvenile salmonids (Oncorhynchus spp. and Salmo spp,), of overlap in food habits of hatchery and wild ...

  Citation × Citation Citation Abstract Copy Title: An investigation of the utilization of four study areas in Yaquina Bay, Oregon, by hatchery and wild juvenile salmonids Author: Myers, Katherine West Whitney Results of a study of spatial and temporal utilization of a tidal river estuary by hatchery and wild juvenile salmonids (Oncorhynchus spp. and Salmo spp,), of overlap in food habits of hatchery and wild juvenile salmonids, and of size and relative abundance of associated fish species are reported in this thesis. The investigation was conducted in Yaquina Bay, Oregon in 1977 and 1978 to provide information for evaluation of concerns over the biological impact of large releases of hatchery salmon on wild fish in the estuary. A 100- X 3-m beach seine was used to sample four beach study areas from July 1977 through December 1978, and a 222-m lampara net was used to sample two channel study areas from March 1978 through October 1978. Approximately 2. 2 million hatchery salmon were released into Yaquina Bay in 1977, and 9.6 million were released in 1978. Tags, fin clips, dye marks, scales, species, release date, external parasites, visceral fat, size, and fin erosion were used to determine hatchery or wild origin of individual salmonids in the catch. Chinook (Oncorhynchus tshawytscha), chum (0. keta), and coho (0. kisutch) salmon, in decreasing order, were the most abundant wild salmonid species, and coho salmon were the most abundant hatchery species. In 1978 wild populations of chum and coho salmon were present in the estuary for 2-3 mo (March-June), and wild Chinook were present during 9 mo (January, April-November). Increase in mean length of wild chum and Chinook, and decrease in mean length of wild coho, indicated that wild chum and Chinook utilized the estuary as a rearing area, and wild coho did not. Lack of overlap in peak migration periods of wild chum (early April), coho (mid May), and chinook (late July-early August) suggests the need to minimize overlap in utilization of the estuary by hatchery and wild juvenile salmonids. The length of residence of hatchery coho in Yaquina Bay was described by the equation: N=N 0 e-kt. The "residency half-life" (E®2) ranged from 1. 7 to 9. 0 days for different No release groups of hatchery coho in 1977 and 1978. Juvenile hatchery coho that remained for an extended period (1-3 mo) in Yaquina Bay during 1977 increased in mean length from 11.5 cm FL in mid July to 21. 0 cm FL in October. Some individuals within summer release groups of hatchery chinook also remained in the estuary for extended periods (> 2 mo)a Groups of juvenile hatchery coho and chinook released into Yaquina Bay earlier in the year (June-August) remained in the estuary for longer periods than groups released later in the year (September-October), Overlap in food habits of hatchery and wild juvenile salmonids in the estuary was C ften high, although overlap was found to vary with species, time, habitat, space, length of estuarine residence, and prey abundance. In terms of biomass, larval and juvenile fish (Clupeidae, Engraulidae, and Osmeridae) were the most important prey organisms of hatchery and wild coho and chinook salmon in Yaquina Bay. Approximately 58 fish species were captured at the study areas in 1977 and 1978, and 17 were identified in the stomach contents of hatchery and wild salmonids. Overlap in spatial and temporal utilization and in food habits of hatchery and wild juvenile salmon in the estuary indicates that the potential for competition between these groups does exist, should space or food resources become a limiting factor. To reduce overlap in spatial and temporal utilization, consideration should be given to not releasing hatchery salmon during peak migration periods of wild chum, coho, and chinook salmon. To reduce length of residence of hatchery coho and chinook released after May, mid to late summer releases should be considered. Title: An investigation of the utilization of four study areas in Yaquina Bay, Oregon, by hatchery and wild juvenile salmonids Author: Myers, Katherine West Whitney Results of a study of spatial and temporal utilization of a tidal river estuary by hatchery and wild juvenile salmonids (Oncorhynchus spp. and Salmo spp,), of overlap in food habits of hatchery and wild juvenile salmonids, and of size and relative abundance of associated fish species are reported in this thesis. The investigation was conducted in Yaquina Bay, Oregon in 1977 and 1978 to provide information for evaluation of concerns over the biological impact of large releases of hatchery salmon on wild fish in the estuary. A 100- X 3-m beach seine was used to sample four beach study areas from July 1977 through December 1978, and a 222-m lampara net was used to sample two channel study areas from March 1978 through October 1978. Approximately 2. 2 million hatchery salmon were released into Yaquina Bay in 1977, and 9.6 million were released in 1978. Tags, fin clips, dye marks, scales, species, release date, external parasites, visceral fat, size, and fin erosion were used to determine hatchery or wild origin of individual salmonids in the catch. Chinook (Oncorhynchus tshawytscha), chum (0. keta), and coho (0. kisutch) salmon, in decreasing order, were the most abundant wild salmonid species, and coho salmon were the most abundant hatchery species. In 1978 wild populations of chum and coho salmon were present in the estuary for 2-3 mo (March-June), and wild Chinook were present during 9 mo (January, April-November). Increase in mean length of wild chum and Chinook, and decrease in mean length of wild coho, indicated that wild chum and Chinook utilized the estuary as a rearing area, and wild coho did not. Lack of overlap in peak migration periods of wild chum (early April), coho (mid May), and chinook (late July-early August) suggests the need to minimize overlap in utilization of the estuary by hatchery and wild juvenile salmonids. The length of residence of hatchery coho in Yaquina Bay was described by the equation: N=N 0 e-kt. The "residency half-life" (E®2) ranged from 1. 7 to 9. 0 days for different No release groups of hatchery coho in 1977 and 1978. Juvenile hatchery coho that remained for an extended period (1-3 mo) in Yaquina Bay during 1977 increased in mean length from 11.5 cm FL in mid July to 21. 0 cm FL in October. Some individuals within summer release groups of hatchery chinook also remained in the estuary for extended periods (> 2 mo)a Groups of juvenile hatchery coho and chinook released into Yaquina Bay earlier in the year (June-August) remained in the estuary for longer periods than groups released later in the year (September-October), Overlap in food habits of hatchery and wild juvenile salmonids in the estuary was C ften high, although overlap was found to vary with species, time, habitat, space, length of estuarine residence, and prey abundance. In terms of biomass, larval and juvenile fish (Clupeidae, Engraulidae, and Osmeridae) were the most important prey organisms of hatchery and wild coho and chinook salmon in Yaquina Bay. Approximately 58 fish species were captured at the study areas in 1977 and 1978, and 17 were identified in the stomach contents of hatchery and wild salmonids. Overlap in spatial and temporal utilization and in food habits of hatchery and wild juvenile salmon in the estuary indicates that the potential for competition between these groups does exist, should space or food resources become a limiting factor. To reduce overlap in spatial and temporal utilization, consideration should be given to not releasing hatchery salmon during peak migration periods of wild chum, coho, and chinook salmon. To reduce length of residence of hatchery coho and chinook released after May, mid to late summer releases should be considered. Close

• 2279. [Article] Eelgrass-macroalgae interactions; context-dependency in upwelling-influenced estuaries

  This dissertation investigates the context-dependency of species interactions between seagrass and macroalgae in upwelling-influenced estuaries. In all coastal systems, nutrient loading is multidirectional, ...

  Citation × Citation Citation Abstract Copy Title: Eelgrass-macroalgae interactions; context-dependency in upwelling-influenced estuaries Author: Hessing-Lewis, Margot, 1979- This dissertation investigates the context-dependency of species interactions between seagrass and macroalgae in upwelling-influenced estuaries. In all coastal systems, nutrient loading is multidirectional, resulting from mostly freshwater and marine inputs. The directionality of nutrient inputs may affect the rate of supply of organic matter to the system. In systems where freshwater nutrient loading dominates, and has increased through time, research shows that blooms of fast-growing macroalgae often result in loss of critical seagrass habitats. In upwelling-influenced systems, marine- based nutrient inputs dominate during the summer, also resulting in blooms of ulvoid macroalgae during these productive months. The dominance of marine nutrients in these estuaries, coupled with additional variation in the physicochemical characteristics of seagrass beds, present novel contexts to study the outcomes of species interactions between the seagrass (Zostera marina L. (eelgrass) and ulvoid macroalgae. I studied these interactions at two different spatial scales that both address the relative importance of marine versus terrestrial nutrient sources on interaction outcome. Regionally, I studied between-estuary, latitudinal patterns in species interactions relative to differences in marine and terrestrial drivers of nutrient loading. Within an estuary, I also compared interactions among zones along an estuarine gradient, where nutrient patterns were reflective of the relative contribution of marine- based nutrients. At both scales of inquiry I employed both observational and experimental approaches to quantify species interaction dynamics. At the regional scale, I used a 5- year observational dataset from four estuaries along the Oregon and Washington coasts to study the relationship between eelgrass and ulvoid macroalgae (Chapter 2). Across latitudes that span ~220 km, macroalgal production was highest in the southern estuaries, and associated with decreased eelgrass production compared to the northern estuaries. However, through time, no estuarine site, regardless of its macroalgal biomass, was associated with declining eelgrass biomass. Contrary to systems where macroalgal production is driven by terrestrial inputs, I found that blooms in upwelling- influenced systems were associated with both marine and terrestrial drivers of nutrient inputs and production. In Coos Bay (South Slough), at the within-estuary scale, I also found differences in macroalgal and eelgrass biomass among sites along an estuarine gradient. Here too, based on a 2-year seasonal dataset of producer dynamics, I found no temporal relationship between eelgrass and macroalgae producer dynamics (Chapter 3). I used a comparative-experimental framework to understand the impact of macroalgal manipulations (additions and removals) on interactions with eelgrass along this gradient. In intertidal seagrass beds in the marine and polyhaline zones of the estuary I found that interaction strength was neutral and sometimes positive. However, in the riverine zone, interaction strength was negative, caused by decreased eelgrass density following macroalgal manipulation. To further examine the mechanisms informing interaction outcomes in the marine zone, a large-scale macroalgal manipulation was conducted, coupled with a mesocosm experiment (Chapter 4). For the mesocosm experiment I manipulated macroalgae and nutrients as in the field, but found dissimilar results. In the mesocosms, where water movement was limited and no tidal action occurred, negative effects of macroalgal addition were found. These were associated with increased light attenuation and decreased sediment oxygen levels. Contrary to these results, I found no macroalgal, or covariate effects in the field experiment. I also manipulated water column nutrients in both experiments, and found limited effects of nutrient enrichment on eelgrass, but not macroalgae, in the mesocosm experiment. Throughout these studies I demonstrated that the mechanisms determining context-dependency in upwelling-influenced estuaries are informed by physical and biogeochemical conditions, coupled with high ambient marine-derived nutrient concentrations. These findings are important to coastal management because they suggest that the strength, direction and mechanisms of interactions are shaped by local abiotic conditions and long-term nutrient regimes, rather than high nutrient concentrations per se. Given the shifting nature of nutrient concentrations in coastal waters associated with both coastal development and climate change, knowledge of context dependency can also be used to assess and forecast future changes in species interactions. Title: Eelgrass-macroalgae interactions; context-dependency in upwelling-influenced estuaries Author: Hessing-Lewis, Margot, 1979- This dissertation investigates the context-dependency of species interactions between seagrass and macroalgae in upwelling-influenced estuaries. In all coastal systems, nutrient loading is multidirectional, resulting from mostly freshwater and marine inputs. The directionality of nutrient inputs may affect the rate of supply of organic matter to the system. In systems where freshwater nutrient loading dominates, and has increased through time, research shows that blooms of fast-growing macroalgae often result in loss of critical seagrass habitats. In upwelling-influenced systems, marine- based nutrient inputs dominate during the summer, also resulting in blooms of ulvoid macroalgae during these productive months. The dominance of marine nutrients in these estuaries, coupled with additional variation in the physicochemical characteristics of seagrass beds, present novel contexts to study the outcomes of species interactions between the seagrass (Zostera marina L. (eelgrass) and ulvoid macroalgae. I studied these interactions at two different spatial scales that both address the relative importance of marine versus terrestrial nutrient sources on interaction outcome. Regionally, I studied between-estuary, latitudinal patterns in species interactions relative to differences in marine and terrestrial drivers of nutrient loading. Within an estuary, I also compared interactions among zones along an estuarine gradient, where nutrient patterns were reflective of the relative contribution of marine- based nutrients. At both scales of inquiry I employed both observational and experimental approaches to quantify species interaction dynamics. At the regional scale, I used a 5- year observational dataset from four estuaries along the Oregon and Washington coasts to study the relationship between eelgrass and ulvoid macroalgae (Chapter 2). Across latitudes that span ~220 km, macroalgal production was highest in the southern estuaries, and associated with decreased eelgrass production compared to the northern estuaries. However, through time, no estuarine site, regardless of its macroalgal biomass, was associated with declining eelgrass biomass. Contrary to systems where macroalgal production is driven by terrestrial inputs, I found that blooms in upwelling- influenced systems were associated with both marine and terrestrial drivers of nutrient inputs and production. In Coos Bay (South Slough), at the within-estuary scale, I also found differences in macroalgal and eelgrass biomass among sites along an estuarine gradient. Here too, based on a 2-year seasonal dataset of producer dynamics, I found no temporal relationship between eelgrass and macroalgae producer dynamics (Chapter 3). I used a comparative-experimental framework to understand the impact of macroalgal manipulations (additions and removals) on interactions with eelgrass along this gradient. In intertidal seagrass beds in the marine and polyhaline zones of the estuary I found that interaction strength was neutral and sometimes positive. However, in the riverine zone, interaction strength was negative, caused by decreased eelgrass density following macroalgal manipulation. To further examine the mechanisms informing interaction outcomes in the marine zone, a large-scale macroalgal manipulation was conducted, coupled with a mesocosm experiment (Chapter 4). For the mesocosm experiment I manipulated macroalgae and nutrients as in the field, but found dissimilar results. In the mesocosms, where water movement was limited and no tidal action occurred, negative effects of macroalgal addition were found. These were associated with increased light attenuation and decreased sediment oxygen levels. Contrary to these results, I found no macroalgal, or covariate effects in the field experiment. I also manipulated water column nutrients in both experiments, and found limited effects of nutrient enrichment on eelgrass, but not macroalgae, in the mesocosm experiment. Throughout these studies I demonstrated that the mechanisms determining context-dependency in upwelling-influenced estuaries are informed by physical and biogeochemical conditions, coupled with high ambient marine-derived nutrient concentrations. These findings are important to coastal management because they suggest that the strength, direction and mechanisms of interactions are shaped by local abiotic conditions and long-term nutrient regimes, rather than high nutrient concentrations per se. Given the shifting nature of nutrient concentrations in coastal waters associated with both coastal development and climate change, knowledge of context dependency can also be used to assess and forecast future changes in species interactions. Close

• 2280. [Article] Identification of optimal broodstock for Pacific Northwest oysters

  The United States Pacific Northwest is well known for its shellfish farming. Historically, commercial harvests were dominated by the native Olympia oyster, Ostrea lurida, but over-exploitation, habitat ...

  Citation × Citation Citation Abstract Copy Title: Identification of optimal broodstock for Pacific Northwest oysters Author: Stick, David A. The United States Pacific Northwest is well known for its shellfish farming. Historically, commercial harvests were dominated by the native Olympia oyster, Ostrea lurida, but over-exploitation, habitat degradation, and competition and predation by non-native species has drastically depleted their densities and extirpated many local populations. As a result, shellfish aquaculture production has shifted to the introduced Pacific oyster, Crassostrea gigas. An underlying objective of this dissertation is the use of molecular genetics to improve our ability to accurately identifying optimal oyster broodstock for either restoration of Olympia oysters or farming of Pacific oysters. The ecological benefits provided by oysters as well as the Olympia oyster's historical significance, has motivated numerous restoration/supplementation efforts but these efforts are proceeding without a clear understanding of the genetic structure among extant populations, which could be substantial as a consequence of limited dispersal, local adaptation and/or anthropogenic impacts. To facilitate this understanding, we isolated and characterized 19 polymorphic microsatellites and used 8 of these to study the genetic structure of 2,712 individuals collected from 25 remnant Olympia oyster populations between the northern tip of Vancouver Island BC and Elkhorn Slough CA. Gene flow among geographically separated extant Olympia oyster populations is surprisingly limited for a marine invertebrate species whose free-swimming larvae are capable of planktonic dispersal as long as favorable water conditions exist. We found a significant correlation between geographic and genetic distances supporting the premise that coastal populations are isolated by distance. Genetic structure among remnant populations was not limited to broad geographic regions but was also present at sub-regional scales in both Puget Sound WA and San Francisco Bay CA. Until it can be determined whether genetically differentiated O. lurida populations are locally adapted, restoration projects and resource managers should be cautious of random mixing or transplantation of stocks where gene flow is restricted. As we transition from our Olympia oyster population analysis to our Pacific oyster quantitative analysis, we recognize that traditional quantitative trait locus (QTL) mapping strategies use crosses among inbred lines to create segregating populations. Unfortunately, even low levels of inbreeding in the Pacific oyster (Crassostrea gigas) can substantially depress economically important quantitative traits such as yield and survival, potentially complicating subsequent QTL analyses. To circumvent this problem, we constructed an integrated linkage map for Pacific oysters, consisting of 65 microsatellite (18 of which were previously unmapped) and 212 AFLP markers using a full-sib cross between phenotypically differentiated outbred families. We identified 10 linkage groups (LG1-LG10) spanning 710.48 cM, with an average genomic coverage of 91.39% and an average distance between markers of 2.62 cM. Average marker saturation was 27.7 per linkage group, ranging between 19 (LG9) and 36 markers (LG3). Using this map we identified 12 quantitative trait loci (QTLs) and 5 potential QTLs in the F1 outcross population of 236 full-sib Pacific oysters for four growth-related morphometric measures, including individual wet live weight, shell length, shell width and shell depth measured at four post-fertilization time points: plant-out (average age of 140 days), first year interim (average age of 358 days), second year interim (average age of 644 days) and harvest (average age of 950 days). Mapped QTLs and potential QTLs accounted for an average of 11.2% of the total phenotypic variation and ranged between 2.1 and 33.1%. Although QTL or potential QTL were mapped to all Pacific oyster linkage groups with the exception of LG2, LG8 and LG9, three groups (LG4, LG10 and LG5) were associated with three or more QTL or potential QTL. We conclude that alleles accounting for a significant proportion of the total phenotypic variation for morphometric measures that influence harvest yield remain segregating within the broodstock of West Coast Pacific oyster selective breeding programs. Title: Identification of optimal broodstock for Pacific Northwest oysters Author: Stick, David A. The United States Pacific Northwest is well known for its shellfish farming. Historically, commercial harvests were dominated by the native Olympia oyster, Ostrea lurida, but over-exploitation, habitat degradation, and competition and predation by non-native species has drastically depleted their densities and extirpated many local populations. As a result, shellfish aquaculture production has shifted to the introduced Pacific oyster, Crassostrea gigas. An underlying objective of this dissertation is the use of molecular genetics to improve our ability to accurately identifying optimal oyster broodstock for either restoration of Olympia oysters or farming of Pacific oysters. The ecological benefits provided by oysters as well as the Olympia oyster's historical significance, has motivated numerous restoration/supplementation efforts but these efforts are proceeding without a clear understanding of the genetic structure among extant populations, which could be substantial as a consequence of limited dispersal, local adaptation and/or anthropogenic impacts. To facilitate this understanding, we isolated and characterized 19 polymorphic microsatellites and used 8 of these to study the genetic structure of 2,712 individuals collected from 25 remnant Olympia oyster populations between the northern tip of Vancouver Island BC and Elkhorn Slough CA. Gene flow among geographically separated extant Olympia oyster populations is surprisingly limited for a marine invertebrate species whose free-swimming larvae are capable of planktonic dispersal as long as favorable water conditions exist. We found a significant correlation between geographic and genetic distances supporting the premise that coastal populations are isolated by distance. Genetic structure among remnant populations was not limited to broad geographic regions but was also present at sub-regional scales in both Puget Sound WA and San Francisco Bay CA. Until it can be determined whether genetically differentiated O. lurida populations are locally adapted, restoration projects and resource managers should be cautious of random mixing or transplantation of stocks where gene flow is restricted. As we transition from our Olympia oyster population analysis to our Pacific oyster quantitative analysis, we recognize that traditional quantitative trait locus (QTL) mapping strategies use crosses among inbred lines to create segregating populations. Unfortunately, even low levels of inbreeding in the Pacific oyster (Crassostrea gigas) can substantially depress economically important quantitative traits such as yield and survival, potentially complicating subsequent QTL analyses. To circumvent this problem, we constructed an integrated linkage map for Pacific oysters, consisting of 65 microsatellite (18 of which were previously unmapped) and 212 AFLP markers using a full-sib cross between phenotypically differentiated outbred families. We identified 10 linkage groups (LG1-LG10) spanning 710.48 cM, with an average genomic coverage of 91.39% and an average distance between markers of 2.62 cM. Average marker saturation was 27.7 per linkage group, ranging between 19 (LG9) and 36 markers (LG3). Using this map we identified 12 quantitative trait loci (QTLs) and 5 potential QTLs in the F1 outcross population of 236 full-sib Pacific oysters for four growth-related morphometric measures, including individual wet live weight, shell length, shell width and shell depth measured at four post-fertilization time points: plant-out (average age of 140 days), first year interim (average age of 358 days), second year interim (average age of 644 days) and harvest (average age of 950 days). Mapped QTLs and potential QTLs accounted for an average of 11.2% of the total phenotypic variation and ranged between 2.1 and 33.1%. Although QTL or potential QTL were mapped to all Pacific oyster linkage groups with the exception of LG2, LG8 and LG9, three groups (LG4, LG10 and LG5) were associated with three or more QTL or potential QTL. We conclude that alleles accounting for a significant proportion of the total phenotypic variation for morphometric measures that influence harvest yield remain segregating within the broodstock of West Coast Pacific oyster selective breeding programs. Close