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• 5671. [Article] Effect of dietary fatty acids, time of feeding and immune response in poultry

  In the presence of internal or external stressors, the body requires sources of energy that aide cells to combat inflammation. Fatty acids are an important source of energy and are vital components of ...

  Citation × Citation Citation Abstract Copy Title: Effect of dietary fatty acids, time of feeding and immune response in poultry Author: Gonzalez, Dulmelis In the presence of internal or external stressors, the body requires sources of energy that aide cells to combat inflammation. Fatty acids are an important source of energy and are vital components of cell membranes. Dietary fatty acids (n-6 and n-3) are of importance in immune function because they are precursors to metabolites that are potent mediators of inflammation. Poultry diets are high in n-6 fatty acids, which exert pro-inflammatory effects, and low in n-3 fatty acids, which tend to be less inflammatory. Delayed access to feed after hatching has been reported to impact the development of organs associated with immunity. Based on this information, two experiments were conducted in broiler chickens to determine the effect of dietary polyunsaturated fatty acid (PUFA) and the influence of time of feeding on bird performance, tissue lipid status, immune responses and expression of cyclooxygenase 2 (COX-2) upon challenge. In experiment 1, birds were fed diets that contained 3.5% oxidized yellow grease (low n-3) or 3.5% canola oil (high n-3). Birds were fed early (<5 hrs post-hatch) or late (>24 hrs post-hatch). Intramuscular injection of lipopolysaccharide (LPS) or phosphate buffered saline (control) was used as the immune challenge. Feeding high n-3 diets resulted in an increase in n-3 fatty acids in the liver in all treatment groups upon LPS challenge (P<0.05). LPS injection led to a decrease in total n-6 fatty acids in the liver when compared with control birds (P<0.05) fed early high n-3 and late low n-3. However, in spleen tissue, upon LPS challenge, increase in total n-3 fatty acids was observed only in birds fed early high n-3 and birds fed late high n-3. Plasma non-esterified fatty acids were lowest in high n-3 birds fed early (P<0.05). The spleen tissue total fat content was lowest in early high and late high n-3 birds (P<0.05). Breast muscle thiobarbituric acid reactive substances (TBARS) were higher in birds fed high n-3 compared to birds fed diets low in n-3 (P< 0.05). The delayed type hypersensitivity response was higher in birds fed high n-3 diet when compared to all other treatments (P<0.05). Thigh muscle of LPS challenged birds from early low n-3 and late high n-3 was significantly higher in TBARS when compared to control birds (P<0.05). There was no difference in final body weight, cut-up yield and organ weight of birds (P>0.05) except liver and thigh muscle weight percents were lowest in birds fed low n-3 (P<0.05). In the second experiment, birds were fed diets containing 3.5% sunflower oil (low n-3) or 3.5% fish oil (high n-3). The birds were either fed early (<5 hrs post hatch) or late (>48 hrs post-hatch). No effect due to time of feeding was observed (P>0.05). Birds fed high n-3 diets had higher C20:5n-3, C22:5n-3, C22:6n-3 and total n-3 fatty acids and birds that were fed a low n-3 diet had higher levels of total n-6 PUFAs (P<0.05). LPS challenged led to a decrease in spleen C22:5n-3 of birds fed late high n-3 when compared to control birds within the same treatment group (P<0.05). LPS challenged birds showed an increase in C20:4n-6, total polyunsaturated fats and total n-6 fatty acids in birds that were late fed low n-3 compared to control birds within the same treatment group (P<0.05). LPS challenged birds from early and late high n-3 had higher liver total saturated fats when compared to control birds of the same diet (P<0.05). LPS challenge led to an increase in liver total n-6 fatty acids in birds fed late low n-3 when compared to control birds within the same treatment (P<0.05). LPS birds from early and late high n-3 diets were higher in total liver n-3 fatty acid content when compared to birds fed low n-3 diets (P<0.05). Plasma isoprostanes showed no difference among treatment groups (P>0.05). Liver vitamin E was higher in control birds from early high n-3 groups when compared to the other treatments (P<0.05). Plasma vitamin E was highest in early low n-3 upon challenge when compared to the other treatments (P<0.05). LPS challenge resulted in an increase in vitamin E in the lung, small intestine and plasma of low n-3 birds. COX-2 expression in the spleen tissue increased due to LPS challenge. Time of feeding and diet had a significant effect on COX-2 protein expression (P<0.05). These results indicate that type of dietary fat and time of feeding may alter the inflammatory response upon challenge in broiler birds. During inflammation, lipid substrates for the activated immune system are provided by fatty acids. Therefore, dietary management strategies directed at attenuating immune tissue lipid content may prove to be beneficial in enhancing bird health and in increasing production performance in broiler chickens. Title: Effect of dietary fatty acids, time of feeding and immune response in poultry Author: Gonzalez, Dulmelis In the presence of internal or external stressors, the body requires sources of energy that aide cells to combat inflammation. Fatty acids are an important source of energy and are vital components of cell membranes. Dietary fatty acids (n-6 and n-3) are of importance in immune function because they are precursors to metabolites that are potent mediators of inflammation. Poultry diets are high in n-6 fatty acids, which exert pro-inflammatory effects, and low in n-3 fatty acids, which tend to be less inflammatory. Delayed access to feed after hatching has been reported to impact the development of organs associated with immunity. Based on this information, two experiments were conducted in broiler chickens to determine the effect of dietary polyunsaturated fatty acid (PUFA) and the influence of time of feeding on bird performance, tissue lipid status, immune responses and expression of cyclooxygenase 2 (COX-2) upon challenge. In experiment 1, birds were fed diets that contained 3.5% oxidized yellow grease (low n-3) or 3.5% canola oil (high n-3). Birds were fed early (<5 hrs post-hatch) or late (>24 hrs post-hatch). Intramuscular injection of lipopolysaccharide (LPS) or phosphate buffered saline (control) was used as the immune challenge. Feeding high n-3 diets resulted in an increase in n-3 fatty acids in the liver in all treatment groups upon LPS challenge (P<0.05). LPS injection led to a decrease in total n-6 fatty acids in the liver when compared with control birds (P<0.05) fed early high n-3 and late low n-3. However, in spleen tissue, upon LPS challenge, increase in total n-3 fatty acids was observed only in birds fed early high n-3 and birds fed late high n-3. Plasma non-esterified fatty acids were lowest in high n-3 birds fed early (P<0.05). The spleen tissue total fat content was lowest in early high and late high n-3 birds (P<0.05). Breast muscle thiobarbituric acid reactive substances (TBARS) were higher in birds fed high n-3 compared to birds fed diets low in n-3 (P< 0.05). The delayed type hypersensitivity response was higher in birds fed high n-3 diet when compared to all other treatments (P<0.05). Thigh muscle of LPS challenged birds from early low n-3 and late high n-3 was significantly higher in TBARS when compared to control birds (P<0.05). There was no difference in final body weight, cut-up yield and organ weight of birds (P>0.05) except liver and thigh muscle weight percents were lowest in birds fed low n-3 (P<0.05). In the second experiment, birds were fed diets containing 3.5% sunflower oil (low n-3) or 3.5% fish oil (high n-3). The birds were either fed early (<5 hrs post hatch) or late (>48 hrs post-hatch). No effect due to time of feeding was observed (P>0.05). Birds fed high n-3 diets had higher C20:5n-3, C22:5n-3, C22:6n-3 and total n-3 fatty acids and birds that were fed a low n-3 diet had higher levels of total n-6 PUFAs (P<0.05). LPS challenged led to a decrease in spleen C22:5n-3 of birds fed late high n-3 when compared to control birds within the same treatment group (P<0.05). LPS challenged birds showed an increase in C20:4n-6, total polyunsaturated fats and total n-6 fatty acids in birds that were late fed low n-3 compared to control birds within the same treatment group (P<0.05). LPS challenged birds from early and late high n-3 had higher liver total saturated fats when compared to control birds of the same diet (P<0.05). LPS challenge led to an increase in liver total n-6 fatty acids in birds fed late low n-3 when compared to control birds within the same treatment (P<0.05). LPS birds from early and late high n-3 diets were higher in total liver n-3 fatty acid content when compared to birds fed low n-3 diets (P<0.05). Plasma isoprostanes showed no difference among treatment groups (P>0.05). Liver vitamin E was higher in control birds from early high n-3 groups when compared to the other treatments (P<0.05). Plasma vitamin E was highest in early low n-3 upon challenge when compared to the other treatments (P<0.05). LPS challenge resulted in an increase in vitamin E in the lung, small intestine and plasma of low n-3 birds. COX-2 expression in the spleen tissue increased due to LPS challenge. Time of feeding and diet had a significant effect on COX-2 protein expression (P<0.05). These results indicate that type of dietary fat and time of feeding may alter the inflammatory response upon challenge in broiler birds. During inflammation, lipid substrates for the activated immune system are provided by fatty acids. Therefore, dietary management strategies directed at attenuating immune tissue lipid content may prove to be beneficial in enhancing bird health and in increasing production performance in broiler chickens. Close

• 5672. [Article] Surface Water and Groundwater Interactions in the Walla Walla River, Northeast Oregon, USA : A Multi-Method Field-Based Approach

  Surface water and groundwater interactions are a key component in the functioning of stream ecosystems. Exchange of water between the stream and the hyporheic zone creates habitat for aquatic organisms ...

  Citation × Citation Citation Abstract Copy Title: Surface Water and Groundwater Interactions in the Walla Walla River, Northeast Oregon, USA : A Multi-Method Field-Based Approach Author: Gryczkowski, Landon Surface water and groundwater interactions are a key component in the functioning of stream ecosystems. Exchange of water between the stream and the hyporheic zone creates habitat for aquatic organisms and serves as a control for stream biogeochemical, thermal, and flow processes. This study takes a multi-method field-based approach to gain a better understanding of exchange processes in the Walla Walla River, Northeast Oregon, USA, with focus on advancing methodologies, spatial and temporal exchange dynamics, fish ecology and habitat, and geomorphic controls on hyporheic exchange. Fiber-optic distributed temperature sensing (DTS) was used to identify, quantify, and map cold-water inflows at the meter scale. Analysis of the maximum and minimum daily temperature traces separated each cold-water inflow into either hyporheic or groundwater-derived. DTS identified a very active hyporheic zone in this system, with a near-equal importance of hyporheic and groundwater inflows. Approximately one-third of the 2-km study reach was influence by cold-water inflows, providing significant cooling in certain areas. Using piezometers in conjunction with DTS provided validation and supplementation of DTS results, increased the reliability of conclusions, and helped to identify and understand specific exchange processes. Piezometer data showed downwelling conditions (negative head differential) except immediately downstream of riffles, with head differentials becoming increasingly negative farther downstream from a riffle. Furthermore, head differentials increased in the negative direction from left bank to right bank, indicating lateral movement of groundwater and more loss of river water from the right bank. Nearest to riffles and river bends, head differentials remained more stable over time, which may indicate that geomorphic structures influence head variations locally, while aquifer levels and dynamics have an increasing influence farther from these structures. Seasonally, head differentials became increasingly negative through the summer into fall as aquifer levels decreased, and areas of the river that lost the most water to the subsurface tended to lose more water at a faster rate as the summer progressed. However, the seasonal trend of head differentials may be counteracted by decreasing bed permeability, yielding little or no temporal change in vertical flux of water through the streambed. During high-flow events, river losses to the subsurface decreased overall; in particular, areas with the greatest water loss at low flows showed reduced losses during high flows. High variability and lack of patterns in the response to high flow events suggests complexity in this process. Temperature-related variables from DTS data were combined with habitat-related variables to determine which variables best explain pool-scale salmonid abundance. Two snorkel surveys of 23 pools within the study reach were performed. The change in temperature across the pool showed the strongest overall relationship to salmonid abundance, particularly Chinook salmon. Chinook salmon showed a stronger preference for specific pools compared to steelhead/rainbow trout. The magnitude of cold-water inflows appears more important than the presence or proportion of the pool receiving cold-water inflows, and salmonid abundance was more strongly explained by hyporheic inflows compared to groundwater. Temperature variables increased in importance relative to habitat variables in the second snorkel sample compared to sample one. The highest river temperatures of the summer occurred between the two sample dates, and this may suggest that salmonids’ affinity for cold-water refuge was enhanced through behavioral adaptation following periods of high temperature approaching the lethal threshold. The combined use of DTS, continuous electrical resistivity/induced polarization profiling, LiDAR, aerial imagery analysis, and field surveys allowed for the quantification of many geomorphic and hydraulic variables known or hypothesized to contribute to surface water and groundwater exchange processes. Regression analysis was used to determine which of these variables best explain the presence and magnitude of both groundwater and hyporheic inflows. For the first time, the cross-sectional area of the hyporheic zone was estimated at high resolution at the reach scale, and decreasing hyporheic cross-sectional area best explained both the presence and magnitude of cold-water inflows of either type. Higher water surface slope and sinuosity/curvature were next in order of importance. The presence of hyporheic inflows was also explained by higher water surface slope, sinuosity, and Reynolds number, while the magnitude of hyporheic inflows was best explained by higher sinuosity. Groundwater inflows were also explained by higher width-to-depth ratio, higher water surface slope, decreasing distance from a stream bank to the bankfull or floodplain extent, and decreasing flow velocity. Lateral processes (e.g. sinuosity) and vertical processes (e.g. water surface slope) were found to be of comparable importance, but lateral processes better explained larger decreases in stream temperature, possibly because lateral subsurface flow paths are longer in distance and duration. Hydraulic conductivity variables did not show up among the most important variables likely because of the difficulty in estimating hydraulic conductivity at the meter scale using electrical geophysical tools. Title: Surface Water and Groundwater Interactions in the Walla Walla River, Northeast Oregon, USA : A Multi-Method Field-Based Approach Author: Gryczkowski, Landon Surface water and groundwater interactions are a key component in the functioning of stream ecosystems. Exchange of water between the stream and the hyporheic zone creates habitat for aquatic organisms and serves as a control for stream biogeochemical, thermal, and flow processes. This study takes a multi-method field-based approach to gain a better understanding of exchange processes in the Walla Walla River, Northeast Oregon, USA, with focus on advancing methodologies, spatial and temporal exchange dynamics, fish ecology and habitat, and geomorphic controls on hyporheic exchange. Fiber-optic distributed temperature sensing (DTS) was used to identify, quantify, and map cold-water inflows at the meter scale. Analysis of the maximum and minimum daily temperature traces separated each cold-water inflow into either hyporheic or groundwater-derived. DTS identified a very active hyporheic zone in this system, with a near-equal importance of hyporheic and groundwater inflows. Approximately one-third of the 2-km study reach was influence by cold-water inflows, providing significant cooling in certain areas. Using piezometers in conjunction with DTS provided validation and supplementation of DTS results, increased the reliability of conclusions, and helped to identify and understand specific exchange processes. Piezometer data showed downwelling conditions (negative head differential) except immediately downstream of riffles, with head differentials becoming increasingly negative farther downstream from a riffle. Furthermore, head differentials increased in the negative direction from left bank to right bank, indicating lateral movement of groundwater and more loss of river water from the right bank. Nearest to riffles and river bends, head differentials remained more stable over time, which may indicate that geomorphic structures influence head variations locally, while aquifer levels and dynamics have an increasing influence farther from these structures. Seasonally, head differentials became increasingly negative through the summer into fall as aquifer levels decreased, and areas of the river that lost the most water to the subsurface tended to lose more water at a faster rate as the summer progressed. However, the seasonal trend of head differentials may be counteracted by decreasing bed permeability, yielding little or no temporal change in vertical flux of water through the streambed. During high-flow events, river losses to the subsurface decreased overall; in particular, areas with the greatest water loss at low flows showed reduced losses during high flows. High variability and lack of patterns in the response to high flow events suggests complexity in this process. Temperature-related variables from DTS data were combined with habitat-related variables to determine which variables best explain pool-scale salmonid abundance. Two snorkel surveys of 23 pools within the study reach were performed. The change in temperature across the pool showed the strongest overall relationship to salmonid abundance, particularly Chinook salmon. Chinook salmon showed a stronger preference for specific pools compared to steelhead/rainbow trout. The magnitude of cold-water inflows appears more important than the presence or proportion of the pool receiving cold-water inflows, and salmonid abundance was more strongly explained by hyporheic inflows compared to groundwater. Temperature variables increased in importance relative to habitat variables in the second snorkel sample compared to sample one. The highest river temperatures of the summer occurred between the two sample dates, and this may suggest that salmonids’ affinity for cold-water refuge was enhanced through behavioral adaptation following periods of high temperature approaching the lethal threshold. The combined use of DTS, continuous electrical resistivity/induced polarization profiling, LiDAR, aerial imagery analysis, and field surveys allowed for the quantification of many geomorphic and hydraulic variables known or hypothesized to contribute to surface water and groundwater exchange processes. Regression analysis was used to determine which of these variables best explain the presence and magnitude of both groundwater and hyporheic inflows. For the first time, the cross-sectional area of the hyporheic zone was estimated at high resolution at the reach scale, and decreasing hyporheic cross-sectional area best explained both the presence and magnitude of cold-water inflows of either type. Higher water surface slope and sinuosity/curvature were next in order of importance. The presence of hyporheic inflows was also explained by higher water surface slope, sinuosity, and Reynolds number, while the magnitude of hyporheic inflows was best explained by higher sinuosity. Groundwater inflows were also explained by higher width-to-depth ratio, higher water surface slope, decreasing distance from a stream bank to the bankfull or floodplain extent, and decreasing flow velocity. Lateral processes (e.g. sinuosity) and vertical processes (e.g. water surface slope) were found to be of comparable importance, but lateral processes better explained larger decreases in stream temperature, possibly because lateral subsurface flow paths are longer in distance and duration. Hydraulic conductivity variables did not show up among the most important variables likely because of the difficulty in estimating hydraulic conductivity at the meter scale using electrical geophysical tools. Close

• 5673. [Article] Historic Survival Rates and Cause-Specific Mortality for Columbian Black-Tailed Deer in Southwest Oregon

  In contrast with other Odocoileus species, Columbian black-tailed deer (Odocoileus hemionus columbianus) population dynamics are not well understood throughout the species’ range. Concerns over apparent ...

  Citation × Citation Citation Abstract Copy Title: Historic Survival Rates and Cause-Specific Mortality for Columbian Black-Tailed Deer in Southwest Oregon Author: Groot, Kevyn A. In contrast with other Odocoileus species, Columbian black-tailed deer (Odocoileus hemionus columbianus) population dynamics are not well understood throughout the species’ range. Concerns over apparent long-term population declines have prompted efforts to fill basic knowledge gaps including estimates of vital rates (fecundity, recruitment and survival) and cause-specific mortality. The Oregon Department of Fish and Wildlife completed an extensive Columbian black-tailed (black-tailed) deer radio-collaring study in Oregon's south Cascade range from 1994 - 2000, with the goal of better understanding and anticipating the effects of different harvest management strategies on deer herds in the region. I utilized this historical data to conduct an in-depth investigation of seasonal sex- and age-specific survival rates and cause-specific mortality rates for marked black-tailed deer. I used known-fate data for 293 male and female radio-collared black-tailed of 3 age classes (yearling, 2-year old, adult) to estimate seasonal survival and investigate a variety of explanatory factors including sex, age class, temporal effects (seasonal, annual and trends across season and year), and time-dependent large-scale regional climate covariates. Variation in survival rates for this population was best explained by an interaction between sex and age class, with decreased probability of survival with increasing age class. The age effect was most pronounced in males, and although female survival in the older age classes was higher compared to male survival as predicted, yearling males had higher survival rates than yearling females. There was strong support for temporal variation in survival between summer and winter seasons, with winter survival best modeled as constant across years and summer survival variable across years. Winter survival was generally higher than summer except in 1997 when winter and summer rates were similar. Despite annual variation in summer survival rates, large-scale climate indices (Southern Oscillation Index, Pacific Decadal Oscillation, and Palmer Drought Severity Index) did not explain any temporal variation in survival rates within seasons. Low survival rates during the summer season, particularly for older males, resulted in low estimates of annual survival in some years. Annual estimates for males ranged from 0.47 - 0.76 for yearlings, 0.29 - 0.60 for 2-year olds and 0.14 - 0.40 for adults across the 6 years of this study. Annual estimates for females were generally higher than for males but were some of the lowest documented for the species, ranging from 0.47 - 0.76 for yearlings, 0.46 - 0.75 for 2-year olds and 0.44 - 0.74 for adults. I used the nonparametric cumulative incidence function estimator (NPCIFE) to generate annual and seasonal cumulative incidence functions for four competing risks: harvest, predation, other low-incidence sources of anthropogenic or natural mortality, and mortality due to unknown sources. Annual and seasonal risk functions were pooled across all years of the study to maximize sample size. As predicted in this system with limited antlerless harvest, cumulative risk of harvest across the entire annual cycle (365 days) was significantly higher for males (0.16, 95% CI = 0.11 - 0.21); a 16% annual cumulative risk compared to just 3% for females (0.03, 95% CI = 0.01 - 0.05). In addition, cause-specific mortality by male age class during the period of highest hunting pressure (general Cascade rifle season) suggested that 2-year-old males had over twice the cumulative risk of legal harvest with 22% of this age class killed by hunters during the general rifle season (0.22, 95% CI = 0.12 - 0.33) compared to 10% of adults (0.10, 95% CI = 0.04 - 0.15). Most yearling males survived the harvest season as cumulative legal harvest risk for yearling males was low (0.02, 95% CI = -0.01 - 0.06) relative to 2-year-olds and adults. Cougars (Puma concolor) were the primary predator of marked black-tailed deer and there was no significant difference in annual cumulative predation risk between the sexes (males: 0.05, 95% CI = 0.02 - 0.08; females: 0.05, 95% CI = 0.03 - 0.08), with only 5% risk of predation each year for both males and females. There was strong evidence that cumulative predation risk for females was higher in winter (0.04, 95% CI = 0.02 - 0.06) compared to summer (0.01, 95% CI = -0.002 - 0.02), and an increase in cumulative risk from February to May provides supportive evidence that females are more susceptible to predation during these months. High survival rates of yearling males with dramatic declines in survival once many of these deer became 2-year olds or older suggest that harvest may have had an additive effect and been the primary cause of low survival rates observed for males. Observed variability in summer survival resulted in variable, and in some years very low, annual survival rates for adult females; a strong contrast to the generally stable annual survival rates reported for other populations of mule deer. The highest estimates of annual survival for yearling males and for females of all age classes (0.74) in 1997 are comparable to the low range of estimates observed in other populations, but in other years estimates are much lower than what has been previously reported for black-tailed deer. These low survival rates might suggest a mechanism resulting in population decline over time, but more information on other vital rates (fecundity, fawn survival, and recruitment), carrying capacity of the system and population size is necessary to understand the population dynamics of black-tailed deer in this region during the 1990's. Properties of the data relative to male age classes in particular (low sample sizes, high censoring rates) decreased precision of these estimates and might have resulted in biased estimates. Adult females had consistently sufficient sample sizes over the course of the study to generate more precise, reliable estimates of survival, particularly in the latter 3 years of the study; these estimates should therefore be viewed with more confidence. Cause-specific mortality rates should be viewed as minimums due to the high number of unknown mortalities (40% of total) in the study population, but they suggest that hunting is the primary source of mortality for adult males and predation has the highest impact on seasonal female mortality rates. Given the historical nature of these results, my estimates should be used as a baseline and foundation for comparison with results from current black-tailed deer research in Oregon. These results have raised potential questions regarding harvest levels on male black-tailed deer in addition to possible resource constraints affecting both sexes on seasonal ranges, and can therefore focus new research to address these concerns. Title: Historic Survival Rates and Cause-Specific Mortality for Columbian Black-Tailed Deer in Southwest Oregon Author: Groot, Kevyn A. In contrast with other Odocoileus species, Columbian black-tailed deer (Odocoileus hemionus columbianus) population dynamics are not well understood throughout the species’ range. Concerns over apparent long-term population declines have prompted efforts to fill basic knowledge gaps including estimates of vital rates (fecundity, recruitment and survival) and cause-specific mortality. The Oregon Department of Fish and Wildlife completed an extensive Columbian black-tailed (black-tailed) deer radio-collaring study in Oregon's south Cascade range from 1994 - 2000, with the goal of better understanding and anticipating the effects of different harvest management strategies on deer herds in the region. I utilized this historical data to conduct an in-depth investigation of seasonal sex- and age-specific survival rates and cause-specific mortality rates for marked black-tailed deer. I used known-fate data for 293 male and female radio-collared black-tailed of 3 age classes (yearling, 2-year old, adult) to estimate seasonal survival and investigate a variety of explanatory factors including sex, age class, temporal effects (seasonal, annual and trends across season and year), and time-dependent large-scale regional climate covariates. Variation in survival rates for this population was best explained by an interaction between sex and age class, with decreased probability of survival with increasing age class. The age effect was most pronounced in males, and although female survival in the older age classes was higher compared to male survival as predicted, yearling males had higher survival rates than yearling females. There was strong support for temporal variation in survival between summer and winter seasons, with winter survival best modeled as constant across years and summer survival variable across years. Winter survival was generally higher than summer except in 1997 when winter and summer rates were similar. Despite annual variation in summer survival rates, large-scale climate indices (Southern Oscillation Index, Pacific Decadal Oscillation, and Palmer Drought Severity Index) did not explain any temporal variation in survival rates within seasons. Low survival rates during the summer season, particularly for older males, resulted in low estimates of annual survival in some years. Annual estimates for males ranged from 0.47 - 0.76 for yearlings, 0.29 - 0.60 for 2-year olds and 0.14 - 0.40 for adults across the 6 years of this study. Annual estimates for females were generally higher than for males but were some of the lowest documented for the species, ranging from 0.47 - 0.76 for yearlings, 0.46 - 0.75 for 2-year olds and 0.44 - 0.74 for adults. I used the nonparametric cumulative incidence function estimator (NPCIFE) to generate annual and seasonal cumulative incidence functions for four competing risks: harvest, predation, other low-incidence sources of anthropogenic or natural mortality, and mortality due to unknown sources. Annual and seasonal risk functions were pooled across all years of the study to maximize sample size. As predicted in this system with limited antlerless harvest, cumulative risk of harvest across the entire annual cycle (365 days) was significantly higher for males (0.16, 95% CI = 0.11 - 0.21); a 16% annual cumulative risk compared to just 3% for females (0.03, 95% CI = 0.01 - 0.05). In addition, cause-specific mortality by male age class during the period of highest hunting pressure (general Cascade rifle season) suggested that 2-year-old males had over twice the cumulative risk of legal harvest with 22% of this age class killed by hunters during the general rifle season (0.22, 95% CI = 0.12 - 0.33) compared to 10% of adults (0.10, 95% CI = 0.04 - 0.15). Most yearling males survived the harvest season as cumulative legal harvest risk for yearling males was low (0.02, 95% CI = -0.01 - 0.06) relative to 2-year-olds and adults. Cougars (Puma concolor) were the primary predator of marked black-tailed deer and there was no significant difference in annual cumulative predation risk between the sexes (males: 0.05, 95% CI = 0.02 - 0.08; females: 0.05, 95% CI = 0.03 - 0.08), with only 5% risk of predation each year for both males and females. There was strong evidence that cumulative predation risk for females was higher in winter (0.04, 95% CI = 0.02 - 0.06) compared to summer (0.01, 95% CI = -0.002 - 0.02), and an increase in cumulative risk from February to May provides supportive evidence that females are more susceptible to predation during these months. High survival rates of yearling males with dramatic declines in survival once many of these deer became 2-year olds or older suggest that harvest may have had an additive effect and been the primary cause of low survival rates observed for males. Observed variability in summer survival resulted in variable, and in some years very low, annual survival rates for adult females; a strong contrast to the generally stable annual survival rates reported for other populations of mule deer. The highest estimates of annual survival for yearling males and for females of all age classes (0.74) in 1997 are comparable to the low range of estimates observed in other populations, but in other years estimates are much lower than what has been previously reported for black-tailed deer. These low survival rates might suggest a mechanism resulting in population decline over time, but more information on other vital rates (fecundity, fawn survival, and recruitment), carrying capacity of the system and population size is necessary to understand the population dynamics of black-tailed deer in this region during the 1990's. Properties of the data relative to male age classes in particular (low sample sizes, high censoring rates) decreased precision of these estimates and might have resulted in biased estimates. Adult females had consistently sufficient sample sizes over the course of the study to generate more precise, reliable estimates of survival, particularly in the latter 3 years of the study; these estimates should therefore be viewed with more confidence. Cause-specific mortality rates should be viewed as minimums due to the high number of unknown mortalities (40% of total) in the study population, but they suggest that hunting is the primary source of mortality for adult males and predation has the highest impact on seasonal female mortality rates. Given the historical nature of these results, my estimates should be used as a baseline and foundation for comparison with results from current black-tailed deer research in Oregon. These results have raised potential questions regarding harvest levels on male black-tailed deer in addition to possible resource constraints affecting both sexes on seasonal ranges, and can therefore focus new research to address these concerns. Close

• 5674. [Article] A UK perspective on marine renewable energy environmental research: Keeping up with a ‘Deploy & Monitor’ philosophy

  There are many drivers for the pursuit of renewable energy extraction from coastal seas. In the United Kingdom these include moving away from fossil fuels to mitigate the impacts of climate change, improving ...

  Citation × Citation Citation Abstract Copy Title: A UK perspective on marine renewable energy environmental research: Keeping up with a ‘Deploy & Monitor’ philosophy Author: Wilson, Ben There are many drivers for the pursuit of renewable energy extraction from coastal seas. In the United Kingdom these include moving away from fossil fuels to mitigate the impacts of climate change, improving energy security by diversifying supply options, increasing wealth generation in outlying coastal communities, and seeking alternative sources of power as existing infrastructure (power stations) near the end of their useful lives. In Scotland these drivers are particularly strong because of the additional factors of decline of North Sea oil reserves; the political pressure not to re-develop nuclear power plants; and the abundant offshore wind, wave and tidal-stream resources. While these drivers are strong, and backed up by ambitious political targets, a variety of constraints currently limit development of a vibrant marine renewables sector in UK coastal waters. In addition to financial, technological and logistical issues, a diversity of environmental restrictions limitprogress of the renewables sector. Many of these environmental issues actually stem from a lack of basic knowledge of how marine renewable energy devices are likely to interact with the receiving environment and vulnerable species (particularly those protected by European legislation such as the Habitats and Species as well as the Birds Directives). Furthermore where negative interactions are known, there may be limited knowledge about, or options for, mitigating these impacts. Strictly applying precautionary principals to these new and diverse technologies with respect to their potential local negative environmental impacts threatens to halt development of these technologies despite their potential benefits for global climate and other environmental issues. This problem applies particularly to wave and tidal-stream technologies which are diverse, new, and without track-record. To overcome this issue, the Scottish government is implementing a staged introduction of these technologies under what has been termed a “Survey-Deploy-&-Monitor” policy. That is, commercial scale devices are being placed singly or in small arrays (< 10 MW) into areas of pre-determined and acceptable environmental sensitivity and then impacts are being quantified through a monitoring program. In parallel to this approach, The Crown Estate (the seabed owner) has performed a series of licensing rounds to lease preferred sites to specific wind, wave and tidal-stream developers. If consented, these sites will represent commercial-scale developments of all three technologies in Scottish and wider UK waters. Part of that consenting progress requires that developers provide evidence (through Environmental Impact Studies and the production of Environmental Statements) that their developments will not harm the surrounding environment. It is these consenting exercises and related fundamental questions about impacts that are currently driving most of the environmental research related to offshore wind and marine renewable technologies in the UK. Research tends to fall into three divisions based on the source of funding and the geographic scope of the issues. At the smallest scale are studies of individual sites of interest to individual developers seeking consents for a specific technology. More generic studies funded by government or industry consortia may be performed to understand environmental issues surrounding a particular group of technologies, installation methods, or operational parameters. In this case, the actual site may be less important. Finally, fundamental research (funded by Research Councils) may be carried out to understand how and why animals use renewable energy relevant sites. Because there are a large number of research studies currently underway at a wide range of scales, sites, and taxa in Scotland and the wider UK, it is not possible to summarize them all in this short talk. Instead, I will outline examples of the three broad areas of environmental research (site/device specific, technology generic and more basic ecology). These examples have also been chosen because they represent an ongoing project, a recently established group of research studies, and a potential new research program. Some of the perhaps less intuitive lessons that have arisen from some of such projects include : 1. The responses of organisms may not be tied to particular brands of device or energy extraction, whether wind, wave, tidal-stream or even oil platform. For fouling organisms the particulars of the substrate might be the important factor rather than the device’s method of energy extraction. Likewise for fish it may be the device complexity and position in the water column that is key to their interactions. 2. Conversely, particular, seemingly unimportant features of devices may have relevance to marine organisms. For example, the color of a turbine may be extremely important for animals maneuvering around the rotors, a duct or the pile. 3. Test centers used to assess full-scale devices may seem like excellent places to also perform environmental research; however care must be taken as the devices in test centers are typically early generation prototypes and may be swapped out frequently. Furthermore activities by other companies at neighboring berths may invalidate site or device specific experiments. 4. Inter-annual variability does not suit the current pace of marine renewables development and careful consideration of the use of control sites and BACI designs should be made. 5. Cumulative impacts of multiple renewable and other developments offer a massive challenge to determining environmental impact. This difficulty represents a significant area of uncertainty for developers seeking consent and may encourage a development race with companies not wanting to have to consider their development relative to all of the others that preceded them. 6. Finally, while much effort is currently being devoted to gathering sufficient data to permit consent and early stage deployments, the significant investments only come when developers set up arrays capable of producing commercially relevant power. At this point there may be a step change in the degree of monitoring required of any potential environmental interactions. Should intolerable impacts be found, then mitigation will be urgently required or an exit strategy implemented. Title: A UK perspective on marine renewable energy environmental research: Keeping up with a ‘Deploy & Monitor’ philosophy Author: Wilson, Ben There are many drivers for the pursuit of renewable energy extraction from coastal seas. In the United Kingdom these include moving away from fossil fuels to mitigate the impacts of climate change, improving energy security by diversifying supply options, increasing wealth generation in outlying coastal communities, and seeking alternative sources of power as existing infrastructure (power stations) near the end of their useful lives. In Scotland these drivers are particularly strong because of the additional factors of decline of North Sea oil reserves; the political pressure not to re-develop nuclear power plants; and the abundant offshore wind, wave and tidal-stream resources. While these drivers are strong, and backed up by ambitious political targets, a variety of constraints currently limit development of a vibrant marine renewables sector in UK coastal waters. In addition to financial, technological and logistical issues, a diversity of environmental restrictions limitprogress of the renewables sector. Many of these environmental issues actually stem from a lack of basic knowledge of how marine renewable energy devices are likely to interact with the receiving environment and vulnerable species (particularly those protected by European legislation such as the Habitats and Species as well as the Birds Directives). Furthermore where negative interactions are known, there may be limited knowledge about, or options for, mitigating these impacts. Strictly applying precautionary principals to these new and diverse technologies with respect to their potential local negative environmental impacts threatens to halt development of these technologies despite their potential benefits for global climate and other environmental issues. This problem applies particularly to wave and tidal-stream technologies which are diverse, new, and without track-record. To overcome this issue, the Scottish government is implementing a staged introduction of these technologies under what has been termed a “Survey-Deploy-&-Monitor” policy. That is, commercial scale devices are being placed singly or in small arrays (< 10 MW) into areas of pre-determined and acceptable environmental sensitivity and then impacts are being quantified through a monitoring program. In parallel to this approach, The Crown Estate (the seabed owner) has performed a series of licensing rounds to lease preferred sites to specific wind, wave and tidal-stream developers. If consented, these sites will represent commercial-scale developments of all three technologies in Scottish and wider UK waters. Part of that consenting progress requires that developers provide evidence (through Environmental Impact Studies and the production of Environmental Statements) that their developments will not harm the surrounding environment. It is these consenting exercises and related fundamental questions about impacts that are currently driving most of the environmental research related to offshore wind and marine renewable technologies in the UK. Research tends to fall into three divisions based on the source of funding and the geographic scope of the issues. At the smallest scale are studies of individual sites of interest to individual developers seeking consents for a specific technology. More generic studies funded by government or industry consortia may be performed to understand environmental issues surrounding a particular group of technologies, installation methods, or operational parameters. In this case, the actual site may be less important. Finally, fundamental research (funded by Research Councils) may be carried out to understand how and why animals use renewable energy relevant sites. Because there are a large number of research studies currently underway at a wide range of scales, sites, and taxa in Scotland and the wider UK, it is not possible to summarize them all in this short talk. Instead, I will outline examples of the three broad areas of environmental research (site/device specific, technology generic and more basic ecology). These examples have also been chosen because they represent an ongoing project, a recently established group of research studies, and a potential new research program. Some of the perhaps less intuitive lessons that have arisen from some of such projects include : 1. The responses of organisms may not be tied to particular brands of device or energy extraction, whether wind, wave, tidal-stream or even oil platform. For fouling organisms the particulars of the substrate might be the important factor rather than the device’s method of energy extraction. Likewise for fish it may be the device complexity and position in the water column that is key to their interactions. 2. Conversely, particular, seemingly unimportant features of devices may have relevance to marine organisms. For example, the color of a turbine may be extremely important for animals maneuvering around the rotors, a duct or the pile. 3. Test centers used to assess full-scale devices may seem like excellent places to also perform environmental research; however care must be taken as the devices in test centers are typically early generation prototypes and may be swapped out frequently. Furthermore activities by other companies at neighboring berths may invalidate site or device specific experiments. 4. Inter-annual variability does not suit the current pace of marine renewables development and careful consideration of the use of control sites and BACI designs should be made. 5. Cumulative impacts of multiple renewable and other developments offer a massive challenge to determining environmental impact. This difficulty represents a significant area of uncertainty for developers seeking consent and may encourage a development race with companies not wanting to have to consider their development relative to all of the others that preceded them. 6. Finally, while much effort is currently being devoted to gathering sufficient data to permit consent and early stage deployments, the significant investments only come when developers set up arrays capable of producing commercially relevant power. At this point there may be a step change in the degree of monitoring required of any potential environmental interactions. Should intolerable impacts be found, then mitigation will be urgently required or an exit strategy implemented. Close

• 5675. [Article] Impacts of earlier emerging steelhead fry of hatchery origin on the social structure, distribution, and growth of wild steelhead fry

  Newly emerged steelhead fry (Oncorhynchus mvkiss) of hatchery and wild origins were studied in laboratory stream channels and natural streams. Objectives of the study were to determine if and how earlier emerging ...

  Citation × Citation Citation Abstract Copy Title: Impacts of earlier emerging steelhead fry of hatchery origin on the social structure, distribution, and growth of wild steelhead fry Author: Noble, Sandra M. (Sandra Marie) Newly emerged steelhead fry (Oncorhynchus mvkiss) of hatchery and wild origins were studied in laboratory stream channels and natural streams. Objectives of the study were to determine if and how earlier emerging hatchery fry influence the emigration, realized densities, growth, habitat use, social structure, and activity patterns of localized populations of wild steelhead fry when the hatchery fry have a competitive advantage conferred by larger size and prior residence. During 1986 and 1987, the above variables were observed daily among hatchery and wild steelhead fry in laboratory stream channels for 8 weeks following emergence in June. The habitat use and social activities for fry of both origins were observed weekly in natural stream reaches from June through August in 1987 to corroborate lab findings. In lab channels, both hatchery and wild fry received 2 treatments: living alone (allopatry) and living together (sympatry). In the lab, fry of hatchery origin emerged 7 to 10 d prior to wild fry and remained larger in size during the 8 weeks of study both years. In natural stream reaches, fry of each origin were observed only in allopatric situations. Wild fry in the field emerged from natural redds while hatchery fry were released in stream reaches as unfed, newly emerged (swim-up) fry. Hatchery and wild fry in lab sections were found to be very similar in their emigration rates, distances to nearest neighbor, growth rates, and use of habitat. Both fry types, regardless of treatment or environment (lab or field), established similar stable social structure and used the same types of aggressive acts. Among all lab groups, once a fry became dominant, it retained that social status to the end of the study period. Significant differences (P<.05 both years) among comparison tests were: 1) in allopatric lab sections, wild fry maintained larger densities than hatchery fry, 2) in sympatry, hatchery fry had a greater tendency to establish stable focal points and social hierarchies more readily, defend larger areas, have better condition, prefer pools with overhead cover more frequently, be more aggressive, and reach stable densities more quickly than the wild fry, 3) fewer hatchery fry in sympatry maintained nomadic positions than wild fry in both treatments, 4) in sympatry, hatchery fry directed more acts of overt aggression toward wild fry than other hatchery fry, 5) wild fry in sympatry usually used defensive or less offensive acts of aggression when interacting with other fry, 6) fry of both origins in natural stream reaches maintained greater distances to their nearest neighbor than fry in allopatric lab sections, 7) dominant hatchery fry in both treatments maintained larger focal areas than subdominant fry, 8) hatchery fry maintained longer lengths than wild fry through the duration of the study, and 9) hatchery fry were more aggressive in sympatry than in allopatry. Potential differences (P<.05 in one year and P<.1 in the other year) were: 1) wild fry in sympatry had lower realized densities, maintained smaller focal areas, had greater proportions of nomadic individuals, and established stable social hierarchies slower than wild fry in allopatric lab sections, 2) wild fry in sympatry had poorer condition than all other fry groups in lab sections, 3) in sympatry, wild fry were the recipients of the majority of aggressive acts perpetrated by hatchery fry and other wild fry and usually assumed the subordinate positions within the social hierarchy, 4) all fry in the lab showed a high preference for pools with overhead cover and low preference for gravel and fines and run areas, and 5) wild fry in allopatric lab sections were more socially active than hatchery fry while the reverse was observed in the natural streams. Any influences that could be attributed to inherent differences between stock origins were probably masked by size differences between fry types. The study would have been more complete had I included sympatric lab sections where wild fry emerged first and where fry types emerged simultaneously, and sympatric reaches in natural streams. Results were further confounded by the limited number of wild adults used for broodstock in the lab segment of this study. Progeny produced from so few adults (5 adults of each sex each year) would have very limited genotypic variation compared to what occurs in natural streams. This may partially explain why some findings from lab sections and natural stream reaches differed. Likewise, genotypic expression among wild fry in lab sections may have varied greatly between years. This could explain differences found between years in behavior of wild fry in similar lab treatments. Although this study does not simulate all possible scenarios, results support suspicions that introductions of hatchery fry of larger size and earlier emergence into streams containing wild stocks could disrupt the social structure and negatively influence the realized densities, spatial distribution, growth, and behavior of wild juveniles in recipient streams. Title: Impacts of earlier emerging steelhead fry of hatchery origin on the social structure, distribution, and growth of wild steelhead fry Author: Noble, Sandra M. (Sandra Marie) Newly emerged steelhead fry (Oncorhynchus mvkiss) of hatchery and wild origins were studied in laboratory stream channels and natural streams. Objectives of the study were to determine if and how earlier emerging hatchery fry influence the emigration, realized densities, growth, habitat use, social structure, and activity patterns of localized populations of wild steelhead fry when the hatchery fry have a competitive advantage conferred by larger size and prior residence. During 1986 and 1987, the above variables were observed daily among hatchery and wild steelhead fry in laboratory stream channels for 8 weeks following emergence in June. The habitat use and social activities for fry of both origins were observed weekly in natural stream reaches from June through August in 1987 to corroborate lab findings. In lab channels, both hatchery and wild fry received 2 treatments: living alone (allopatry) and living together (sympatry). In the lab, fry of hatchery origin emerged 7 to 10 d prior to wild fry and remained larger in size during the 8 weeks of study both years. In natural stream reaches, fry of each origin were observed only in allopatric situations. Wild fry in the field emerged from natural redds while hatchery fry were released in stream reaches as unfed, newly emerged (swim-up) fry. Hatchery and wild fry in lab sections were found to be very similar in their emigration rates, distances to nearest neighbor, growth rates, and use of habitat. Both fry types, regardless of treatment or environment (lab or field), established similar stable social structure and used the same types of aggressive acts. Among all lab groups, once a fry became dominant, it retained that social status to the end of the study period. Significant differences (P<.05 both years) among comparison tests were: 1) in allopatric lab sections, wild fry maintained larger densities than hatchery fry, 2) in sympatry, hatchery fry had a greater tendency to establish stable focal points and social hierarchies more readily, defend larger areas, have better condition, prefer pools with overhead cover more frequently, be more aggressive, and reach stable densities more quickly than the wild fry, 3) fewer hatchery fry in sympatry maintained nomadic positions than wild fry in both treatments, 4) in sympatry, hatchery fry directed more acts of overt aggression toward wild fry than other hatchery fry, 5) wild fry in sympatry usually used defensive or less offensive acts of aggression when interacting with other fry, 6) fry of both origins in natural stream reaches maintained greater distances to their nearest neighbor than fry in allopatric lab sections, 7) dominant hatchery fry in both treatments maintained larger focal areas than subdominant fry, 8) hatchery fry maintained longer lengths than wild fry through the duration of the study, and 9) hatchery fry were more aggressive in sympatry than in allopatry. Potential differences (P<.05 in one year and P<.1 in the other year) were: 1) wild fry in sympatry had lower realized densities, maintained smaller focal areas, had greater proportions of nomadic individuals, and established stable social hierarchies slower than wild fry in allopatric lab sections, 2) wild fry in sympatry had poorer condition than all other fry groups in lab sections, 3) in sympatry, wild fry were the recipients of the majority of aggressive acts perpetrated by hatchery fry and other wild fry and usually assumed the subordinate positions within the social hierarchy, 4) all fry in the lab showed a high preference for pools with overhead cover and low preference for gravel and fines and run areas, and 5) wild fry in allopatric lab sections were more socially active than hatchery fry while the reverse was observed in the natural streams. Any influences that could be attributed to inherent differences between stock origins were probably masked by size differences between fry types. The study would have been more complete had I included sympatric lab sections where wild fry emerged first and where fry types emerged simultaneously, and sympatric reaches in natural streams. Results were further confounded by the limited number of wild adults used for broodstock in the lab segment of this study. Progeny produced from so few adults (5 adults of each sex each year) would have very limited genotypic variation compared to what occurs in natural streams. This may partially explain why some findings from lab sections and natural stream reaches differed. Likewise, genotypic expression among wild fry in lab sections may have varied greatly between years. This could explain differences found between years in behavior of wild fry in similar lab treatments. Although this study does not simulate all possible scenarios, results support suspicions that introductions of hatchery fry of larger size and earlier emergence into streams containing wild stocks could disrupt the social structure and negatively influence the realized densities, spatial distribution, growth, and behavior of wild juveniles in recipient streams. Close

• 5676. [Article] The legal and regulatory setting affecting timber supply on Oregon's public lands

  Graduation date:

  Citation × Citation Citation Abstract Copy Title: The legal and regulatory setting affecting timber supply on Oregon's public lands Author: Peckman, Nancy Graduation date: Title: The legal and regulatory setting affecting timber supply on Oregon's public lands Author: Peckman, Nancy Graduation date: Close

• 5677. [Article] Survival Rates and Cause-Specific Mortality of Mule Deer in South-Central Oregon

  It is critical for wildlife managers to understand the population dynamics of a harvested species, particularly for ungulates, which are a valuable wildlife resource. Due to concerns that mule deer (Odocoileus ...

  Citation × Citation Citation Abstract Copy Title: Survival Rates and Cause-Specific Mortality of Mule Deer in South-Central Oregon Author: Mulligan, Elizabeth M. It is critical for wildlife managers to understand the population dynamics of a harvested species, particularly for ungulates, which are a valuable wildlife resource. Due to concerns that mule deer (Odocoileus hemionus) populations in Oregon were declining, more comprehensive data on population vital rates and the factors potentially affecting them were needed by resource managers. To meet this research need, Oregon Department of Fish and Wildlife implemented a seven year study to investigate habitat use and survival of mule deer in eastern Oregon. From 2005-2012, the agency radiocollared 621 mule deer in south-central Oregon in order to gain more comprehensive information about seasonal movement, seasonal and annual survival, and changes in habitat use for the population. I used the radio-telemetry data from this larger study to investigate mule deer survival rates and cause-specific mortality and the effects of deer seasonal distributions, movement behavior, and environmental factors such as annual and climatic variation. I used known-fate data for 408 adult female radio-collared mule deer to estimate monthly survival rates and to investigate a variety of factors that might affect these rates including seasonal distribution, temporal effects (seasonal, annual, and trends across season and year), movement behavior, and climatic covariates on differing scales. Variation in survival rates for this population of female mule deer in eastern Oregon was best explained by an additive effect of migration behavior, fall migration period, and precipitation levels on individual winter ranges. Survival was significantly higher for migratory deer than residents. Both groups had lower survival during the fall migration period (Oct-Nov) and a positive linear relationship between survival and winter precipitation in individual winter ranges. Annual survival estimates for migrants ranged from 0.81-0.82, which is similar to other findings, but survival rates for residents (0.76- 0.77) were low in comparison to survival rates for adult female mule deer in other parts of their range. I used a nonparametric cumulative incidence function estimator (NPCIFE) to generate annual cumulative incidence functions separately for males and females due to differing risks associated with each sex. The four competing sources of mortality I included in this analysis for males were legal harvest, illegal harvest, predation, and starvation, disease, vehicle or fence-collision combined as one category (i.e., other). For females in investigated predation, human-associated mortality (vehicle or fence), illegal harvest, and natural causes (starvation and disease). Annual risk functions were pooled across all years of the study to maximize sample size. For males, the cumulative risk was highest for legal harvest (0.249, 95%CI=0.172-0.326), with predation the next highest cause of mortality for this sex (0.104, 95%CI=0.042-0.611). For females, the cumulative risk was highest for predation, (0.044, 95%CI=0.028-0.065) with anthropogenic causes (0.038, 95%CI=0.021-0.054) and illegal harvest (0.031, 95%CI=0.17-0.054) also important sources of mortality. Higher monthly survival rates of migrants compared to residents (across all months of the biological cycle) suggested that leaving for potentially higher quality summer foraging grounds outweighed the cost of traveling through unfamiliar habitats and energy expenditure from migration. Conversely, it may also imply that the summer ranges for residents had a negative effect on survival due to habitat quality or human disturbance. Both migrants and residents had lower monthly survival during the fall migration period (Oct - Nov). Female mule deer were excluded from the state-managed bow and rifle hunting season during this study, but females may experience the negative effects of human disturbance associated with fall hunting activities. This time of year is also energetically costly for females, being that some may still be nursing, which could have an additive effect to the energy used to migrate or avoid human disturbance. Winter precipitation also had positive effect on survival for both groups, possibly because increased average winter precipitation resulted in increased winter forage quantity and quality. My results suggest that female survival rates observed during my study are on the low end of the range reported for this species and may be contributing to population declines of mule deer in Oregon. Annual estimates of male survival were also low, but it is unclear how that might contribute to overall population declines without more information on annual and seasonal variation in male survival. Surprisingly, I observed high levels of illegal harvest on female deer and evidence that female survival during the fall migration period, which overlaps Oregon’s legal harvest season, was lower than other times of the year. It is unclear why the fall migration period negatively affects both migrants and resident deer similarly, but future research should attempt to determine the specific factors that are negatively impacting mule deer survival during this time period in south-central Oregon. In addition, as human development in the area continues to grow, it is important to consider migration paths and the habitat quality of both summer and winter ranges. My results suggested that conditions may differ between summer ranges in particular, for residents vs. migrants, and understanding these differences may be the key to increasing survival of female mule deer in Oregon. Sharing information from this study with law enforcement and the general public may be the first step towards increasing awareness of, and thereby reducing, the relatively high levels of illegal harvest I documented for the female population. Future research should focus on investigating the differences in habitat quality for residents versus migrants, the factors that decrease survival during fall migration for both groups, and the social and economic factors that contribute to the illegal harvest of female mule deer in eastern Oregon. Title: Survival Rates and Cause-Specific Mortality of Mule Deer in South-Central Oregon Author: Mulligan, Elizabeth M. It is critical for wildlife managers to understand the population dynamics of a harvested species, particularly for ungulates, which are a valuable wildlife resource. Due to concerns that mule deer (Odocoileus hemionus) populations in Oregon were declining, more comprehensive data on population vital rates and the factors potentially affecting them were needed by resource managers. To meet this research need, Oregon Department of Fish and Wildlife implemented a seven year study to investigate habitat use and survival of mule deer in eastern Oregon. From 2005-2012, the agency radiocollared 621 mule deer in south-central Oregon in order to gain more comprehensive information about seasonal movement, seasonal and annual survival, and changes in habitat use for the population. I used the radio-telemetry data from this larger study to investigate mule deer survival rates and cause-specific mortality and the effects of deer seasonal distributions, movement behavior, and environmental factors such as annual and climatic variation. I used known-fate data for 408 adult female radio-collared mule deer to estimate monthly survival rates and to investigate a variety of factors that might affect these rates including seasonal distribution, temporal effects (seasonal, annual, and trends across season and year), movement behavior, and climatic covariates on differing scales. Variation in survival rates for this population of female mule deer in eastern Oregon was best explained by an additive effect of migration behavior, fall migration period, and precipitation levels on individual winter ranges. Survival was significantly higher for migratory deer than residents. Both groups had lower survival during the fall migration period (Oct-Nov) and a positive linear relationship between survival and winter precipitation in individual winter ranges. Annual survival estimates for migrants ranged from 0.81-0.82, which is similar to other findings, but survival rates for residents (0.76- 0.77) were low in comparison to survival rates for adult female mule deer in other parts of their range. I used a nonparametric cumulative incidence function estimator (NPCIFE) to generate annual cumulative incidence functions separately for males and females due to differing risks associated with each sex. The four competing sources of mortality I included in this analysis for males were legal harvest, illegal harvest, predation, and starvation, disease, vehicle or fence-collision combined as one category (i.e., other). For females in investigated predation, human-associated mortality (vehicle or fence), illegal harvest, and natural causes (starvation and disease). Annual risk functions were pooled across all years of the study to maximize sample size. For males, the cumulative risk was highest for legal harvest (0.249, 95%CI=0.172-0.326), with predation the next highest cause of mortality for this sex (0.104, 95%CI=0.042-0.611). For females, the cumulative risk was highest for predation, (0.044, 95%CI=0.028-0.065) with anthropogenic causes (0.038, 95%CI=0.021-0.054) and illegal harvest (0.031, 95%CI=0.17-0.054) also important sources of mortality. Higher monthly survival rates of migrants compared to residents (across all months of the biological cycle) suggested that leaving for potentially higher quality summer foraging grounds outweighed the cost of traveling through unfamiliar habitats and energy expenditure from migration. Conversely, it may also imply that the summer ranges for residents had a negative effect on survival due to habitat quality or human disturbance. Both migrants and residents had lower monthly survival during the fall migration period (Oct - Nov). Female mule deer were excluded from the state-managed bow and rifle hunting season during this study, but females may experience the negative effects of human disturbance associated with fall hunting activities. This time of year is also energetically costly for females, being that some may still be nursing, which could have an additive effect to the energy used to migrate or avoid human disturbance. Winter precipitation also had positive effect on survival for both groups, possibly because increased average winter precipitation resulted in increased winter forage quantity and quality. My results suggest that female survival rates observed during my study are on the low end of the range reported for this species and may be contributing to population declines of mule deer in Oregon. Annual estimates of male survival were also low, but it is unclear how that might contribute to overall population declines without more information on annual and seasonal variation in male survival. Surprisingly, I observed high levels of illegal harvest on female deer and evidence that female survival during the fall migration period, which overlaps Oregon’s legal harvest season, was lower than other times of the year. It is unclear why the fall migration period negatively affects both migrants and resident deer similarly, but future research should attempt to determine the specific factors that are negatively impacting mule deer survival during this time period in south-central Oregon. In addition, as human development in the area continues to grow, it is important to consider migration paths and the habitat quality of both summer and winter ranges. My results suggested that conditions may differ between summer ranges in particular, for residents vs. migrants, and understanding these differences may be the key to increasing survival of female mule deer in Oregon. Sharing information from this study with law enforcement and the general public may be the first step towards increasing awareness of, and thereby reducing, the relatively high levels of illegal harvest I documented for the female population. Future research should focus on investigating the differences in habitat quality for residents versus migrants, the factors that decrease survival during fall migration for both groups, and the social and economic factors that contribute to the illegal harvest of female mule deer in eastern Oregon. Close

• 5678. [Article] Incorporation of diet information derived from Bayesian stable isotope mixing models into mass-balanced marine ecosystem models : a case study from the Marennes-Oléron Estuary, France

  This thesis presents two related studies on the methodology for creating, and subsequently analyzing, an inverse food web model of an intertidal seagrass bed. The first study (Chapter 2) describes, for ...

  Citation × Citation Citation Abstract Copy Title: Incorporation of diet information derived from Bayesian stable isotope mixing models into mass-balanced marine ecosystem models : a case study from the Marennes-Oléron Estuary, France Author: Pacella, Stephen Roger This thesis presents two related studies on the methodology for creating, and subsequently analyzing, an inverse food web model of an intertidal seagrass bed. The first study (Chapter 2) describes, for the first time in the literature, a method for incorporating isotopic information gained from Bayesian mixing models into an inverse food web model. The second study (Chapter 3) analyzes the results of this food web model from an ecological perspective, which includes the first complete description of the carbon budget of an intertidal seagrass food web incorporating isotopic information. Linear inverse modeling (LIM) is a technique that estimates a complete network of flows in an under-determined system (e.g., a food web) using a combination of site-specific data and previously published data. This estimation of complete flow networks of food webs in marine ecosystems is becoming more recognized as a powerful tool for understanding ecosystem functioning. However, diets and consumption rates of organisms are often difficult or impossible to accurately and reliably measure in the field, resulting in a large amount of uncertainty in the magnitude of consumption flows and resource partitioning in food web models. In order to address this issue, Chapter 2 utilized stable isotope data to help aid in estimating these unknown flows. δ¹³C and δ¹⁵N isotope data of consumers and producers in the Marennes-Oleron seagrass system were used in Bayesian mixing models; the output of which were then used to constrain consumption flows in an inverse analysis food web model of the seagrass ecosystem. We hypothesized that incorporating the diet information gained from the stable isotope mixing models would result in a more constrained food web model. In order to test this, two inverse food web models were built to track the flow of carbon through the seagrass food web on an annual basis, with units of mg C m⁻² d⁻¹. The first model (Traditional LIM) included all available data, with the exception of the diet constraints formed from the stable isotope mixing models. The second model (Isotope LIM) was identical to the Traditional LIM, but included the SIAR diet constraints. Both models were identical in structure, and intended to model the same Marennes- Oleron intertidal seagrass bed. Each model consisted of 27 compartments (24 living, 3 detrital) and 175 flows. Comparisons between the outputs of the models showed the addition of the SIAR-derived isotopic diet constraints further constrained the solution range of all food web flows on average by 26%. Flows that were directly affected by an isotopic diet constraint were 45% further constrained on average. These results confirmed our hypothesis that incorporation of the isotope information would result in a more constrained food web model, and demonstrated the benefit of utilizing multi-tracer stable isotope information in ecosystem models. In Chapter 3, Ecological Network Analysis (ENA) was used to investigate the functional ecology of the system. The majority of seagrass food web studies thus far have relied on trophic marker analyses (i.e. stable isotopes, fatty acids) to investigate food sources and trophic positions, and as a result, few studies have examined seagrass beds from a perspective of whole-ecosystem functioning. By quantifying the Marennes- Oleron seagrass food web using linear inverse modeling coupled with results from isotopic mixing models, this study investigated the relative trophic importance of primary producers in the system, the trophic structure of the seagrass bed flora and fauna, the relative importance of allochthonous versus autochthonous carbon, and both the sequestration and export of organic carbon to the surrounding environment. Additionally, results of these analyses were compared with other coastal systems, including a neighboring bare mudflat located in the Marennes-Oleron estuary. Grazing rates indicated that microphytobenthos was directly consumed about 7 times more than Zostera, while a novel metric of total food web dependency derived from network analysis showed the consumer compartments relied upon microphytobenthos 22 time more than on Z. noltii via direct and indirect pathways. Meiofauna was found to provide an important link between primary production and detritus with upper trophic levels (i.e. fish). Autochthonous carbon was utilized over 4 times more than allochthonous carbon by the seagrass food web in total, and the system was shown to be a net carbon sink. Our analysis supported the concept that seagrass meadows have a high metabolic capacity and the ability to accumulate large sedimentary carbon pools (e.g., carbon sequestration), which are important climate-regulating ecosystem services. ENA revealed the Oleron seagrass bed to be a relatively mature, stable system internally, with strong connections via energy transport to and from surrounding environments. To the best of the authors' knowledge, this study was the first to fully characterize the carbon budget of an intertidal seagrass food web utilizing probabilistic methods. Title: Incorporation of diet information derived from Bayesian stable isotope mixing models into mass-balanced marine ecosystem models : a case study from the Marennes-Oléron Estuary, France Author: Pacella, Stephen Roger This thesis presents two related studies on the methodology for creating, and subsequently analyzing, an inverse food web model of an intertidal seagrass bed. The first study (Chapter 2) describes, for the first time in the literature, a method for incorporating isotopic information gained from Bayesian mixing models into an inverse food web model. The second study (Chapter 3) analyzes the results of this food web model from an ecological perspective, which includes the first complete description of the carbon budget of an intertidal seagrass food web incorporating isotopic information. Linear inverse modeling (LIM) is a technique that estimates a complete network of flows in an under-determined system (e.g., a food web) using a combination of site-specific data and previously published data. This estimation of complete flow networks of food webs in marine ecosystems is becoming more recognized as a powerful tool for understanding ecosystem functioning. However, diets and consumption rates of organisms are often difficult or impossible to accurately and reliably measure in the field, resulting in a large amount of uncertainty in the magnitude of consumption flows and resource partitioning in food web models. In order to address this issue, Chapter 2 utilized stable isotope data to help aid in estimating these unknown flows. δ¹³C and δ¹⁵N isotope data of consumers and producers in the Marennes-Oleron seagrass system were used in Bayesian mixing models; the output of which were then used to constrain consumption flows in an inverse analysis food web model of the seagrass ecosystem. We hypothesized that incorporating the diet information gained from the stable isotope mixing models would result in a more constrained food web model. In order to test this, two inverse food web models were built to track the flow of carbon through the seagrass food web on an annual basis, with units of mg C m⁻² d⁻¹. The first model (Traditional LIM) included all available data, with the exception of the diet constraints formed from the stable isotope mixing models. The second model (Isotope LIM) was identical to the Traditional LIM, but included the SIAR diet constraints. Both models were identical in structure, and intended to model the same Marennes- Oleron intertidal seagrass bed. Each model consisted of 27 compartments (24 living, 3 detrital) and 175 flows. Comparisons between the outputs of the models showed the addition of the SIAR-derived isotopic diet constraints further constrained the solution range of all food web flows on average by 26%. Flows that were directly affected by an isotopic diet constraint were 45% further constrained on average. These results confirmed our hypothesis that incorporation of the isotope information would result in a more constrained food web model, and demonstrated the benefit of utilizing multi-tracer stable isotope information in ecosystem models. In Chapter 3, Ecological Network Analysis (ENA) was used to investigate the functional ecology of the system. The majority of seagrass food web studies thus far have relied on trophic marker analyses (i.e. stable isotopes, fatty acids) to investigate food sources and trophic positions, and as a result, few studies have examined seagrass beds from a perspective of whole-ecosystem functioning. By quantifying the Marennes- Oleron seagrass food web using linear inverse modeling coupled with results from isotopic mixing models, this study investigated the relative trophic importance of primary producers in the system, the trophic structure of the seagrass bed flora and fauna, the relative importance of allochthonous versus autochthonous carbon, and both the sequestration and export of organic carbon to the surrounding environment. Additionally, results of these analyses were compared with other coastal systems, including a neighboring bare mudflat located in the Marennes-Oleron estuary. Grazing rates indicated that microphytobenthos was directly consumed about 7 times more than Zostera, while a novel metric of total food web dependency derived from network analysis showed the consumer compartments relied upon microphytobenthos 22 time more than on Z. noltii via direct and indirect pathways. Meiofauna was found to provide an important link between primary production and detritus with upper trophic levels (i.e. fish). Autochthonous carbon was utilized over 4 times more than allochthonous carbon by the seagrass food web in total, and the system was shown to be a net carbon sink. Our analysis supported the concept that seagrass meadows have a high metabolic capacity and the ability to accumulate large sedimentary carbon pools (e.g., carbon sequestration), which are important climate-regulating ecosystem services. ENA revealed the Oleron seagrass bed to be a relatively mature, stable system internally, with strong connections via energy transport to and from surrounding environments. To the best of the authors' knowledge, this study was the first to fully characterize the carbon budget of an intertidal seagrass food web utilizing probabilistic methods. Close

• 5679. [Article] The Responses of Slope-spawning Flatfish to Environmental Variability in the Eastern Bering Sea

  When adult spawning and juvenile settling locations of marine fishes are geographically separated, their early life history stages must rely on transport and their own behavior to move them toward suitable ...

  Citation × Citation Citation Abstract Copy Title: The Responses of Slope-spawning Flatfish to Environmental Variability in the Eastern Bering Sea Author: Vestfals, Cathleen D. When adult spawning and juvenile settling locations of marine fishes are geographically separated, their early life history stages must rely on transport and their own behavior to move them toward suitable habitats for successful recruitment to the juvenile phase. Variations in climate may reduce the availability of spawning and juvenile nursery habitats and alter ocean circulation patterns, which can disrupt dispersal pathways and affect life cycle closure. This research focused on two commercially- and ecologically-important flatfish species in the eastern Bering Sea (EBS), Greenland halibut (Reinhardtius hippoglossoides) and Pacific halibut (Hippoglossus stenolepis), which may be especially sensitive to climate variability due to strong seasonally and ontogenetically variable distributions and extended pelagic larval phases. Data from fishery-dependent and fishery-independent sources were analyzed to determine the influence of environmental variability on adult habitat use, thus gaining a uniquely comprehensive range of seasonal and geographic coverage of each species' distribution. Transport along and across the Bering Slope was characterized from 23 years (1982 - 2004) of simulations from a Regional Ocean Modeling System (ROMS) ocean circulation model, with the expectation that changes in the strength and position of the Bering Slope Current (BSC) would affect recruitment, and that circulation features along and across the shelf edge would be strongly influenced by atmospheric forcing. To understand the physical mechanisms of larval delivery to shelf nursery areas, Greenland and Pacific halibut dispersal pathways were simulated from their source (e.g., spawning areas over the continental slope) to settlement locations (e.g., juvenile nursery areas on the continental shelf) using DisMELS (Dispersal Model for Early Life Stages), an individual-based particle-tracking model. Spatial patterns of dispersal were characterized for each species and for years with contrasting settlement success to understand the influence of local oceanographic and atmospheric conditions on dispersal corridor use. Adult Greenland and Pacific halibut exhibited strong and contrasting responses to changes in temperature on the shelf, with catches decreasing and increasing, respectively, at approximately 1°C. The effect of temperature was not as prominent along the slope, suggesting that slope habitats may provide some insulation from shelf-associated environmental variability, particularly for Greenland halibut. With warming, Greenland halibut exhibited more of a bathymetric shift in distribution, while the shift was more latitudinal for Pacific halibut. Habitat partitioning may, in part, explain differences in Greenland and Pacific halibut adult distributions. Analysis of modeled circulation revealed strong variations in the strength and position of the BSC, with changes in along-shelf and cross-shelf flow associated with changes in recruitment. Greenland halibut benefitted from decreased along-shelf and on-shelf flow, while Pacific halibut benefitted from on-shelf flows through Bering and Pribilof canyons. Variability in transport and the BSC position was strongly influenced by winds, ice cover, and large-scale climatic drivers. Greenland and Pacific halibut dispersal pathways varied between years, with distinct differences in dispersal characteristics found between the two species. In general, Greenland halibut connected to shelf nursery areas via more northern corridors, while Pacific halibut connected through more southern ones. In years with poor settlement success, the reverse pattern was observed. Greenland halibut dispersal metrics were strongly correlated with along- and cross-shelf transport, as well as NW along-shelf winds and ice, while Pacific halibut had strong associations with SW onshelf winds. Spawning time and location, along with climate-induced changes in circulation, appear to differentially affect Greenland and Pacific halibut dispersal pathways, which can lead to variations in their recruitment. Overall, Greenland and Pacific halibut had contrasting responses to similar environmental forcing, and predicted climate change is expected to impact these species in different ways. With increasing warming on the EBS shelf, they will likely further partition their habitats, with Greenland halibut finding colder refuges along the slope and Pacific halibut inhabiting larger portions of the shelf. Climate-induced changes in circulation were found to affect the transport of halibut eggs and larvae and their recruitment to the juvenile phase, which suggests an important role in their slope-shelf connectivity. Results of this study suggest that Greenland and Pacific halibut use different mechanisms to move from their spawning locations along the slope to their settlement areas on the shelf, and that environmental conditions that increase slope-shelf connectivity for one species will likely result in reduced connectivity for the other. This research improves our understanding of how slopespawning flatfish respond to a changing ocean environment, which is important for effective management of their populations, as predicted climate change will likely alter their habitat use and population dynamics. Title: The Responses of Slope-spawning Flatfish to Environmental Variability in the Eastern Bering Sea Author: Vestfals, Cathleen D. When adult spawning and juvenile settling locations of marine fishes are geographically separated, their early life history stages must rely on transport and their own behavior to move them toward suitable habitats for successful recruitment to the juvenile phase. Variations in climate may reduce the availability of spawning and juvenile nursery habitats and alter ocean circulation patterns, which can disrupt dispersal pathways and affect life cycle closure. This research focused on two commercially- and ecologically-important flatfish species in the eastern Bering Sea (EBS), Greenland halibut (Reinhardtius hippoglossoides) and Pacific halibut (Hippoglossus stenolepis), which may be especially sensitive to climate variability due to strong seasonally and ontogenetically variable distributions and extended pelagic larval phases. Data from fishery-dependent and fishery-independent sources were analyzed to determine the influence of environmental variability on adult habitat use, thus gaining a uniquely comprehensive range of seasonal and geographic coverage of each species' distribution. Transport along and across the Bering Slope was characterized from 23 years (1982 - 2004) of simulations from a Regional Ocean Modeling System (ROMS) ocean circulation model, with the expectation that changes in the strength and position of the Bering Slope Current (BSC) would affect recruitment, and that circulation features along and across the shelf edge would be strongly influenced by atmospheric forcing. To understand the physical mechanisms of larval delivery to shelf nursery areas, Greenland and Pacific halibut dispersal pathways were simulated from their source (e.g., spawning areas over the continental slope) to settlement locations (e.g., juvenile nursery areas on the continental shelf) using DisMELS (Dispersal Model for Early Life Stages), an individual-based particle-tracking model. Spatial patterns of dispersal were characterized for each species and for years with contrasting settlement success to understand the influence of local oceanographic and atmospheric conditions on dispersal corridor use. Adult Greenland and Pacific halibut exhibited strong and contrasting responses to changes in temperature on the shelf, with catches decreasing and increasing, respectively, at approximately 1°C. The effect of temperature was not as prominent along the slope, suggesting that slope habitats may provide some insulation from shelf-associated environmental variability, particularly for Greenland halibut. With warming, Greenland halibut exhibited more of a bathymetric shift in distribution, while the shift was more latitudinal for Pacific halibut. Habitat partitioning may, in part, explain differences in Greenland and Pacific halibut adult distributions. Analysis of modeled circulation revealed strong variations in the strength and position of the BSC, with changes in along-shelf and cross-shelf flow associated with changes in recruitment. Greenland halibut benefitted from decreased along-shelf and on-shelf flow, while Pacific halibut benefitted from on-shelf flows through Bering and Pribilof canyons. Variability in transport and the BSC position was strongly influenced by winds, ice cover, and large-scale climatic drivers. Greenland and Pacific halibut dispersal pathways varied between years, with distinct differences in dispersal characteristics found between the two species. In general, Greenland halibut connected to shelf nursery areas via more northern corridors, while Pacific halibut connected through more southern ones. In years with poor settlement success, the reverse pattern was observed. Greenland halibut dispersal metrics were strongly correlated with along- and cross-shelf transport, as well as NW along-shelf winds and ice, while Pacific halibut had strong associations with SW onshelf winds. Spawning time and location, along with climate-induced changes in circulation, appear to differentially affect Greenland and Pacific halibut dispersal pathways, which can lead to variations in their recruitment. Overall, Greenland and Pacific halibut had contrasting responses to similar environmental forcing, and predicted climate change is expected to impact these species in different ways. With increasing warming on the EBS shelf, they will likely further partition their habitats, with Greenland halibut finding colder refuges along the slope and Pacific halibut inhabiting larger portions of the shelf. Climate-induced changes in circulation were found to affect the transport of halibut eggs and larvae and their recruitment to the juvenile phase, which suggests an important role in their slope-shelf connectivity. Results of this study suggest that Greenland and Pacific halibut use different mechanisms to move from their spawning locations along the slope to their settlement areas on the shelf, and that environmental conditions that increase slope-shelf connectivity for one species will likely result in reduced connectivity for the other. This research improves our understanding of how slopespawning flatfish respond to a changing ocean environment, which is important for effective management of their populations, as predicted climate change will likely alter their habitat use and population dynamics. Close

• 5680. [Article] Implications of cougar prey selection and demography on population dynamics of elk in northeast Oregon

  Mule deer (Odocoileus hemionus hemionus) and Rocky Mountain elk (Cervus canadensis nelsoni; hereafter elk) populations in northeast Oregon have declined in the past 10 to 20 years. Concurrent with these ...

  Citation × Citation Citation Abstract Copy Title: Implications of cougar prey selection and demography on population dynamics of elk in northeast Oregon Author: Clark, Darren A. Mule deer (Odocoileus hemionus hemionus) and Rocky Mountain elk (Cervus canadensis nelsoni; hereafter elk) populations in northeast Oregon have declined in the past 10 to 20 years. Concurrent with these declines, cougar (Puma concolor) populations have apparently increased, leading to speculation that predation by cougars may be responsible for declining ungulate populations. However, empirical data on cougar diets, kill rates, and prey selection are lacking to support this speculation. Furthermore, the common assumption that cougar populations have increased in northeast Oregon may not be well founded because cougar populations in other areas within the Pacific Northwest region have declined in recent years. My primary research objectives were to (1) estimate kill rates and prey selection by cougars in northeast Oregon, (2) document causes of mortality and estimate survival rates for cougars, (3) estimate population growth rates of cougars in northeast Oregon and simulate the effects of hypothetical lethal control efforts on the cougar population, and (4) investigate the relative influence of top-down, bottom-up, and climatic factors for limiting population growth rates of elk in northeast Oregon. Results from my research will help guide cougar and elk management in northeast Oregon and provide a framework for assessing relative effects of top-down, bottom-up, and abiotic factors on population growth rates of ungulates in this and other areas. I implemented a 3-year study in northeast Oregon to investigate diets, kill rates, and prey selection of cougars in a multiple-prey system to better understand mechanisms by which cougars may influence ungulate populations. During my research, 25 adult cougars were captured and fitted with Global Positioning System (GPS) collars to identify kill sites. I monitored predation sequences of these cougars for 7,642 days and located the remains of 1,213 prey items killed by cougars. Cougars killed ungulates at an average rate of 1.03 per week (95% CI = 0.92 – 1.14); however, ungulate kill rates were variable and influenced by the season and demographic classification of cougars. Cougars killed ungulates 1.55 (95% CI = 1.47 – 1.66) times more frequently during summer (May-Oct) than during winter (Nov-Apr), but killed similar amounts of ungulate biomass (8.05 kg/day; 95% CI = 6.74 – 9.35) throughout the year. Cougars killed ungulates more frequently in summer because juvenile ungulates comprised most of the diet and were smaller on average than ungulate prey killed in winter. Female cougars with kittens killed more frequently (kills/day) than males or solitary females. After accounting for the additional biomass of kittens in cougar family groups, male cougars killed on average more biomass of ungulate prey per day than did females (R = 0.41, P < 0.001), and female cougars killed more biomass of prey per day as a function of the number and age of their kittens (R = 0.60, P < 0.001). Patterns of prey selection were influenced by season and demographic classification of cougars. Female cougars selected elk calves during summer and deer fawns during winter. In contrast, male cougars selected elk calves and yearling elk during summer and elk calves during winter. My results strongly supported the hypothesis that cougar predation is influenced by season, gender, and reproductive status of the cougar and these patterns in cougar predation may be generalizable among ecosystems. The observed selection for juvenile elk and deer suggested a possible mechanism by which cougars could negatively affect population growth rates of ungulates. I investigated survival and documented causes of mortality for radio-collared cougars at 3 study areas in Oregon during 1989 – 2011. Mortality due to hunter harvest was the most common cause of death for cougars in the Catherine Creek study area and the study area combining Wenaha, Sled Springs, and Mt. Emily Wildlife Management Units (WSM study area) in northeast Oregon. In contrast, natural mortality was the most common cause of death for cougars in the Jackson Creek study area in southwest Oregon. Annual survival rates of adult males were lowest at Catherine Creek when it was legal to hunt cougars with dogs (Ŝ = 0.57), but increased following the prohibition of this hunting practice (Ŝ = 0.86). This latter survival rate was similar to those observed at Jackson Creek (Ŝ = 0.78) and WSM (Ŝ = 0.82). Regardless of whether hunting of cougars with dogs was permitted, annual survival rates of adult females were similar among study areas (Catherine Creek Ŝ = 0.86; WSM Ŝ = 0.85; Jackson Creek Ŝ = 0.85). I did not document an effect of age on cougar survival rates in the Catherine Creek study area, which I attributed to selective harvest of prime-aged, male cougars when it was legal to hunt cougars with dogs. In contrast, I observed an effect of age on annual survival in both the WSM and Jackson Creek study areas. These results indicate that sub-adult males had significantly lower survival rates than sub-adult females, but survival rates of males and females were similar by age 4 or 5 years. My results suggest that survival rates of cougars in areas where hunting cougars with dogs is illegal should be substantially higher than areas where use of dogs is legal. I used estimates of cougar vital rates from empirical data collected in northeast Oregon to parameterize a Leslie projection matrix model to estimate deterministic and stochastic population growth rates of cougars in northeast Oregon when hunting cougars with dogs was legal (1989 - 1994) and illegal (2002 - 2011). A model cougar population in northeast Oregon that was hunted with dogs increased at a mean stochastic growth rate of 21% per year (λ[subscript s] = 1.21). Similarly, I found that a model cougar population that was subjected to hunting without dogs increased at a rate of 17% per year (λ[subscript s] = 1.17). Given that hunting cougars with dogs typically results in increased harvest and reduced survival rates of cougars, it was unexpected that the cougar population subjected to hunting with dogs was increasing at a faster rate than one that was not hunted with dogs. However, cougar populations in Oregon were subjected to low harvest rates when hunting cougars with dogs was legal and harvest was male biased. This resulted in high survival rates of female cougars and correspondingly high population growth rates. The Oregon Cougar Management Plan allows the Oregon Department of Fish and Wildlife to administratively reduce cougar populations to benefit ungulate populations, reduce human-cougar conflicts, and limit livestock depredation. Consequently, I was interested in modeling the effects of a hypothetical lethal control effort on a local cougar population. Using empirically-derived vital rates and a deterministic Leslie matrix model, I found that the proportion of the cougar population that would need to be removed annually to achieve a 50% population reduction within 3 years was 28% assuming a closed population, and 48% assuming maximum immigration rates into the population. Using a stochastic Leslie matrix model, I also determined that the model cougar population would likely return to its pre-removal size in 6 years assuming a closed population, and 2 years assuming maximum immigration rates. These model results indicate that current management practices and harvest regulations, combined with short-term, intensive, and localized population reductions, are unlikely to negatively affect the short-term viability of cougar populations in northeast Oregon. However, at this time, it is not known if intensive lethal control efforts funded by state agencies will be cost-effective (i.e., increased sales of tags to hunt deer and elk will offset the costs of control efforts). Further research is needed to investigate the cost-effectiveness of cougar control efforts in Oregon. I developed a Leslie matrix population model, parameterized with empirically-derived vital rates for elk in northeast Oregon, to investigate the relative influence on elk population growth rates of (1) survival and pregnancy, and (2) top-down, bottom-up, and climatic variables. I then estimated the effect of varying the strength of top-down factors on growth rates of elk populations. Growth rates of the model elk population were most sensitive to changes in adult female survival, but due to the inherent empirical variation in juvenile survival rates explained the overwhelming majority of variation in model population growth rates (r² = 0.92). Harvest of female elk had a strong negative effect on model population growth rates of elk (r² = 0.63). An index of cougar density was inversely related to population growth rates of elk in my model (r² = 0.38). A delay in mean date of birth was associated with reduced juvenile survival, but this had a minimal effect on population growth rates in my model (r² = 0.06). Climatic variables, which were used as surrogates for nutritional condition of females, had minimal effects on population growth rates. Likewise, elk density had almost no effect on population growth rates (r² = 0.002). The results of my model provided a novel finding that cougars can be a strong limiting factor on elk populations. Wildlife managers should consider the potential top-down effects of cougars and other predators as a limiting factor on elk populations. Title: Implications of cougar prey selection and demography on population dynamics of elk in northeast Oregon Author: Clark, Darren A. Mule deer (Odocoileus hemionus hemionus) and Rocky Mountain elk (Cervus canadensis nelsoni; hereafter elk) populations in northeast Oregon have declined in the past 10 to 20 years. Concurrent with these declines, cougar (Puma concolor) populations have apparently increased, leading to speculation that predation by cougars may be responsible for declining ungulate populations. However, empirical data on cougar diets, kill rates, and prey selection are lacking to support this speculation. Furthermore, the common assumption that cougar populations have increased in northeast Oregon may not be well founded because cougar populations in other areas within the Pacific Northwest region have declined in recent years. My primary research objectives were to (1) estimate kill rates and prey selection by cougars in northeast Oregon, (2) document causes of mortality and estimate survival rates for cougars, (3) estimate population growth rates of cougars in northeast Oregon and simulate the effects of hypothetical lethal control efforts on the cougar population, and (4) investigate the relative influence of top-down, bottom-up, and climatic factors for limiting population growth rates of elk in northeast Oregon. Results from my research will help guide cougar and elk management in northeast Oregon and provide a framework for assessing relative effects of top-down, bottom-up, and abiotic factors on population growth rates of ungulates in this and other areas. I implemented a 3-year study in northeast Oregon to investigate diets, kill rates, and prey selection of cougars in a multiple-prey system to better understand mechanisms by which cougars may influence ungulate populations. During my research, 25 adult cougars were captured and fitted with Global Positioning System (GPS) collars to identify kill sites. I monitored predation sequences of these cougars for 7,642 days and located the remains of 1,213 prey items killed by cougars. Cougars killed ungulates at an average rate of 1.03 per week (95% CI = 0.92 – 1.14); however, ungulate kill rates were variable and influenced by the season and demographic classification of cougars. Cougars killed ungulates 1.55 (95% CI = 1.47 – 1.66) times more frequently during summer (May-Oct) than during winter (Nov-Apr), but killed similar amounts of ungulate biomass (8.05 kg/day; 95% CI = 6.74 – 9.35) throughout the year. Cougars killed ungulates more frequently in summer because juvenile ungulates comprised most of the diet and were smaller on average than ungulate prey killed in winter. Female cougars with kittens killed more frequently (kills/day) than males or solitary females. After accounting for the additional biomass of kittens in cougar family groups, male cougars killed on average more biomass of ungulate prey per day than did females (R = 0.41, P < 0.001), and female cougars killed more biomass of prey per day as a function of the number and age of their kittens (R = 0.60, P < 0.001). Patterns of prey selection were influenced by season and demographic classification of cougars. Female cougars selected elk calves during summer and deer fawns during winter. In contrast, male cougars selected elk calves and yearling elk during summer and elk calves during winter. My results strongly supported the hypothesis that cougar predation is influenced by season, gender, and reproductive status of the cougar and these patterns in cougar predation may be generalizable among ecosystems. The observed selection for juvenile elk and deer suggested a possible mechanism by which cougars could negatively affect population growth rates of ungulates. I investigated survival and documented causes of mortality for radio-collared cougars at 3 study areas in Oregon during 1989 – 2011. Mortality due to hunter harvest was the most common cause of death for cougars in the Catherine Creek study area and the study area combining Wenaha, Sled Springs, and Mt. Emily Wildlife Management Units (WSM study area) in northeast Oregon. In contrast, natural mortality was the most common cause of death for cougars in the Jackson Creek study area in southwest Oregon. Annual survival rates of adult males were lowest at Catherine Creek when it was legal to hunt cougars with dogs (Ŝ = 0.57), but increased following the prohibition of this hunting practice (Ŝ = 0.86). This latter survival rate was similar to those observed at Jackson Creek (Ŝ = 0.78) and WSM (Ŝ = 0.82). Regardless of whether hunting of cougars with dogs was permitted, annual survival rates of adult females were similar among study areas (Catherine Creek Ŝ = 0.86; WSM Ŝ = 0.85; Jackson Creek Ŝ = 0.85). I did not document an effect of age on cougar survival rates in the Catherine Creek study area, which I attributed to selective harvest of prime-aged, male cougars when it was legal to hunt cougars with dogs. In contrast, I observed an effect of age on annual survival in both the WSM and Jackson Creek study areas. These results indicate that sub-adult males had significantly lower survival rates than sub-adult females, but survival rates of males and females were similar by age 4 or 5 years. My results suggest that survival rates of cougars in areas where hunting cougars with dogs is illegal should be substantially higher than areas where use of dogs is legal. I used estimates of cougar vital rates from empirical data collected in northeast Oregon to parameterize a Leslie projection matrix model to estimate deterministic and stochastic population growth rates of cougars in northeast Oregon when hunting cougars with dogs was legal (1989 - 1994) and illegal (2002 - 2011). A model cougar population in northeast Oregon that was hunted with dogs increased at a mean stochastic growth rate of 21% per year (λ[subscript s] = 1.21). Similarly, I found that a model cougar population that was subjected to hunting without dogs increased at a rate of 17% per year (λ[subscript s] = 1.17). Given that hunting cougars with dogs typically results in increased harvest and reduced survival rates of cougars, it was unexpected that the cougar population subjected to hunting with dogs was increasing at a faster rate than one that was not hunted with dogs. However, cougar populations in Oregon were subjected to low harvest rates when hunting cougars with dogs was legal and harvest was male biased. This resulted in high survival rates of female cougars and correspondingly high population growth rates. The Oregon Cougar Management Plan allows the Oregon Department of Fish and Wildlife to administratively reduce cougar populations to benefit ungulate populations, reduce human-cougar conflicts, and limit livestock depredation. Consequently, I was interested in modeling the effects of a hypothetical lethal control effort on a local cougar population. Using empirically-derived vital rates and a deterministic Leslie matrix model, I found that the proportion of the cougar population that would need to be removed annually to achieve a 50% population reduction within 3 years was 28% assuming a closed population, and 48% assuming maximum immigration rates into the population. Using a stochastic Leslie matrix model, I also determined that the model cougar population would likely return to its pre-removal size in 6 years assuming a closed population, and 2 years assuming maximum immigration rates. These model results indicate that current management practices and harvest regulations, combined with short-term, intensive, and localized population reductions, are unlikely to negatively affect the short-term viability of cougar populations in northeast Oregon. However, at this time, it is not known if intensive lethal control efforts funded by state agencies will be cost-effective (i.e., increased sales of tags to hunt deer and elk will offset the costs of control efforts). Further research is needed to investigate the cost-effectiveness of cougar control efforts in Oregon. I developed a Leslie matrix population model, parameterized with empirically-derived vital rates for elk in northeast Oregon, to investigate the relative influence on elk population growth rates of (1) survival and pregnancy, and (2) top-down, bottom-up, and climatic variables. I then estimated the effect of varying the strength of top-down factors on growth rates of elk populations. Growth rates of the model elk population were most sensitive to changes in adult female survival, but due to the inherent empirical variation in juvenile survival rates explained the overwhelming majority of variation in model population growth rates (r² = 0.92). Harvest of female elk had a strong negative effect on model population growth rates of elk (r² = 0.63). An index of cougar density was inversely related to population growth rates of elk in my model (r² = 0.38). A delay in mean date of birth was associated with reduced juvenile survival, but this had a minimal effect on population growth rates in my model (r² = 0.06). Climatic variables, which were used as surrogates for nutritional condition of females, had minimal effects on population growth rates. Likewise, elk density had almost no effect on population growth rates (r² = 0.002). The results of my model provided a novel finding that cougars can be a strong limiting factor on elk populations. Wildlife managers should consider the potential top-down effects of cougars and other predators as a limiting factor on elk populations. Close