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• 5661. [Article] Taste reactions in Columbian black-tailed deer

  This study involved the use of the two-choice preference test to determine the taste reactions of buck and doe Columbian black-tailed deer (Odocoileus hemionus columbianus) to ascending concentrations ...

  Citation × Citation Citation Abstract Copy Title: Taste reactions in Columbian black-tailed deer Author: Rice, Patrick Ralph This study involved the use of the two-choice preference test to determine the taste reactions of buck and doe Columbian black-tailed deer (Odocoileus hemionus columbianus) to ascending concentrations of water extracts of Douglas fir, red alder, cascara, western hemlock and bitterbrush; to an ethanol extract of Douglas fir, and to the organic acids - citric, malic, quinic, and succinic. Also, the water extracts of Douglas fir and western hemlock, the Douglas fir ethanol extract, and acetic and malic acids were tested in the presence of butyric acid. Responses to Douglas fir and western hemlock water extracts and the Douglas fir ethanol extract were also determined while in the presence of an odorous extract of fish, PF Extract (Fraction G). Animals were separated by sex, and penned in groups of two or three animals per pen. All groups were fed pelleted alfalfa hay and pelleted concentrate, ad libitum. Each response was determined by expressing the intake of the test solution at a given concentration as a percent of the total fluid intake for two, 24-hour periods. Responses were plotted graphically by sex and compared to threshold values for intake. In preliminary tests with water, a 95% confidence interval was established from a theoretical mean intake of 50%. The upper confidence level was 56% intake, with the lower level being 44% intake. Thus, intake of test fluid from 44% to 56% intake was described as the nondiscrimination zone. The preference threshold was set at 80% intake, and the rejection threshold at 20% intake. The sensitivity levels (the point at which discrimination first occurred) of the bucks for the water extracts were (ml extract/100 ml water): Douglas fir, 0. 63; red alder, 0. 05; cascara, 0. 0125; western hemlock, 0. 48; and bitterbrush, 0. 025. The sensitivity for the ethanol extract of Douglas fir was 0. 14. All sensitivity responses were preference reactions. The sensitivity levels of the does for the water extracts were (ml/100 ml): Douglas fir, 0. 05; red alder, 0. 05; cascara, 2. 24; western hemlock, 0. 20; and bitterbrush, 0. 025. The sensitivity for the ethanol extract of Douglas fir was 0. 10. All sensitivity responses were preference reactions except the response to red alder extract. The preference threshold (test fluid 80% or more of total fluid intake) was crossed by the bucks in response to the water extracts of Douglas fir at 1.52 ml/100 ml, western hemlock at 1.48 ml/100 ml, and bitterbrush at 0. 34 ml/ 100 ml. The preference threshold was crossed by the does in response to the water extracts of Douglas fir at 2.94 ml/100 ml and western hemlock at 1.52 ml/ 100 ml. The does exhibited the only 20% rejection response to the browse extracts, with the ethanol extract of Douglas fir prompting rejection at 2. 96 ml/100ml. The sensitivity level of the bucks for citric acid was 0.072 ml/ 100 ml; for -malic acid 0.004 ml/100 ml; for quinic acid 0. 434 ml/ 100 ml; and for succinic acid 0. 00063 ml/100 ml. All sensitivity responses were preference reactions except the response to quinic acid. The sensitivity levels exhibited by the does were all rejections at levels of 0. 0016 ml/ 100 ml for citric and succinic acids and 0.00063 ml/100 ml for malic and quinic acids. The preference threshold was exhibited by the bucks in response to malic acid at 0.01 m1/100 ml. The responses of the bucks crossed the rejection threshold at 2.50 ml/ 100 ml for citric acid and 0. 442 ml /100 ml for succinic acid. Responses of the does that first crossed the rejection threshold were prompted by citric acid at 0.504 ml/100 ml, malic acid at 0. 120 ml/ 100 ml, quinic acid at 0. 395 ml/100 ml, and succinic acid at 0. 060 ml/100 ml. The presence of butyric acid in cotton patches at the top of the fluid containers had no influence on the taste response of the bucks to the test solutions. Also, butyric acid had no influence on the taste responses of the does to test solutions of acetic acid and Douglas fir water extract, but resulted in an increase (P < 0. 05) in the intake of malic acid and a decrease (P < 0. 05) in the intake of western hemlock extract and Douglas fir ethanol extract. The presence of PF Extract (Fraction G) did not influence the taste response of the bucks to western hemlock extract, but resulted in a decreased response to test solutions of both Douglas fir extracts. PF Extract had no influence on the response of the does to the test solutions. Title: Taste reactions in Columbian black-tailed deer Author: Rice, Patrick Ralph This study involved the use of the two-choice preference test to determine the taste reactions of buck and doe Columbian black-tailed deer (Odocoileus hemionus columbianus) to ascending concentrations of water extracts of Douglas fir, red alder, cascara, western hemlock and bitterbrush; to an ethanol extract of Douglas fir, and to the organic acids - citric, malic, quinic, and succinic. Also, the water extracts of Douglas fir and western hemlock, the Douglas fir ethanol extract, and acetic and malic acids were tested in the presence of butyric acid. Responses to Douglas fir and western hemlock water extracts and the Douglas fir ethanol extract were also determined while in the presence of an odorous extract of fish, PF Extract (Fraction G). Animals were separated by sex, and penned in groups of two or three animals per pen. All groups were fed pelleted alfalfa hay and pelleted concentrate, ad libitum. Each response was determined by expressing the intake of the test solution at a given concentration as a percent of the total fluid intake for two, 24-hour periods. Responses were plotted graphically by sex and compared to threshold values for intake. In preliminary tests with water, a 95% confidence interval was established from a theoretical mean intake of 50%. The upper confidence level was 56% intake, with the lower level being 44% intake. Thus, intake of test fluid from 44% to 56% intake was described as the nondiscrimination zone. The preference threshold was set at 80% intake, and the rejection threshold at 20% intake. The sensitivity levels (the point at which discrimination first occurred) of the bucks for the water extracts were (ml extract/100 ml water): Douglas fir, 0. 63; red alder, 0. 05; cascara, 0. 0125; western hemlock, 0. 48; and bitterbrush, 0. 025. The sensitivity for the ethanol extract of Douglas fir was 0. 14. All sensitivity responses were preference reactions. The sensitivity levels of the does for the water extracts were (ml/100 ml): Douglas fir, 0. 05; red alder, 0. 05; cascara, 2. 24; western hemlock, 0. 20; and bitterbrush, 0. 025. The sensitivity for the ethanol extract of Douglas fir was 0. 10. All sensitivity responses were preference reactions except the response to red alder extract. The preference threshold (test fluid 80% or more of total fluid intake) was crossed by the bucks in response to the water extracts of Douglas fir at 1.52 ml/100 ml, western hemlock at 1.48 ml/100 ml, and bitterbrush at 0. 34 ml/ 100 ml. The preference threshold was crossed by the does in response to the water extracts of Douglas fir at 2.94 ml/100 ml and western hemlock at 1.52 ml/ 100 ml. The does exhibited the only 20% rejection response to the browse extracts, with the ethanol extract of Douglas fir prompting rejection at 2. 96 ml/100ml. The sensitivity level of the bucks for citric acid was 0.072 ml/ 100 ml; for -malic acid 0.004 ml/100 ml; for quinic acid 0. 434 ml/ 100 ml; and for succinic acid 0. 00063 ml/100 ml. All sensitivity responses were preference reactions except the response to quinic acid. The sensitivity levels exhibited by the does were all rejections at levels of 0. 0016 ml/ 100 ml for citric and succinic acids and 0.00063 ml/100 ml for malic and quinic acids. The preference threshold was exhibited by the bucks in response to malic acid at 0.01 m1/100 ml. The responses of the bucks crossed the rejection threshold at 2.50 ml/ 100 ml for citric acid and 0. 442 ml /100 ml for succinic acid. Responses of the does that first crossed the rejection threshold were prompted by citric acid at 0.504 ml/100 ml, malic acid at 0. 120 ml/ 100 ml, quinic acid at 0. 395 ml/100 ml, and succinic acid at 0. 060 ml/100 ml. The presence of butyric acid in cotton patches at the top of the fluid containers had no influence on the taste response of the bucks to the test solutions. Also, butyric acid had no influence on the taste responses of the does to test solutions of acetic acid and Douglas fir water extract, but resulted in an increase (P < 0. 05) in the intake of malic acid and a decrease (P < 0. 05) in the intake of western hemlock extract and Douglas fir ethanol extract. The presence of PF Extract (Fraction G) did not influence the taste response of the bucks to western hemlock extract, but resulted in a decreased response to test solutions of both Douglas fir extracts. PF Extract had no influence on the response of the does to the test solutions. Close

• 5662. [Article] The Oregon sockeye salmon virus : A. Biophysical biochemical characteristics B. antigenic relationship to two other salmonid viruses

  The Oregon sockeye salmon virus (OSV) was isolated from diseased sockeye salmon (Oncorhynchus nerka) fingerlings in 1958 by J. L. Fryer. Experimentation performed prior to the research reported herein ...

  Citation × Citation Citation Abstract Copy Title: The Oregon sockeye salmon virus : A. Biophysical biochemical characteristics B. antigenic relationship to two other salmonid viruses Author: McCain, Bruce B. The Oregon sockeye salmon virus (OSV) was isolated from diseased sockeye salmon (Oncorhynchus nerka) fingerlings in 1958 by J. L. Fryer. Experimentation performed prior to the research reported herein indicated that the OSV contained essential lipids, was 100 to 300 mμ in size, and possessed RNA (presumptively identified by 5-bromodeoxyuridine treatment of OSV-infected cell cultures). In the present investigation, OSV was propagated in one of two cell lines derived from the embryonic tissues of either sockeye or chinook (O. tshawytscha) salmon. Infectious cell culture medium was purified by differential centrifugation alone, or in combination with RNase and DNase treatment, and rate-zonal sucrose gradient centrifugation. OSV suspensions had a propensity for forming viral aggregates during differential centrifugation, presumably caused by pelleting virions in the presence of host cell debris and serum proteins. Partially purified virus suspensions were fractionated into four visible bands by rate-zonal or isopycnic sucrose gradient centrifugation. Most virus infectivity was detected in two closely associated bands in the middle of the gradient. Evidence suggested that the more dense, faster sedimenting band contained infectious virus and the other band was composed of incomplete, noninfectious virus particles. The sucrose density of the virus band was determined to be 1.16 g/cm³. The two other visible bands, one above and one below the presumably heterogeneous virus band, were considered to represent nonviral material complexed with varying amounts of virus. Large amounts of virus infectivity were lost either during sucrose gradient centrifugation or when sucrose concentrations were reduced in gradient fractions by dilution and/or dialysis. Purified suspensions of OSV were treated with hot perchloric acid in order to extract viral nucleic acid. RNA and DNA concentrations in the extracts were estimated with the orcinol and diphenylamine tests. Concentrations of RNA were at least 14 times higher than those of DNA. Viral nucleic acid was also extracted from purified ³²P-labeled OSV suspensions by the phenol method at 4°C. Spectral properties of the resulting nucleic acid solutions indicated that they contained relatively large amounts of protein. Viral nuclei acid formed a single band at densities of 1.58 to 1.59 g/cm³ when subjected to isopycnic cesium sulfate gradient centrifugation. Rate-zonal glycerol gradient centrifugation of ³²P-OSV nucleic acid resulted in the formation of a diffuse band of radioactivity with its peak at 26 S and a pronounced shoulder at 37 S. RNase treatment of aliquots from glycerol gradient fractions reduced all trichloroacetic acid-precipitable ³²P-radioactivity by 85 to 97%. Anion exchange chromatography of alkaline-hydrolyzed ³²P-viral nucleic acid was used to determine its base composition. Percentage base compositions were cytidylic acid, 25.8 ± 0.6%; adenylic acid, 23.0 ± 0.8%; uridylic acid, 27.7 ± 0.6%; and guanylic acid, 23.4 ± 0.4%. The fore-mentioned experimental data demonstrate that the OSV virion contains single-stranded RNA. Rabbit-immune sera were produced against OSV, infectious hematopoietic necrosis (IHN) virus, and Sacramento River chinook disease (SRCD) virus. The latter two viruses were isolated from diseased sockeye and chinook salmon, respectively. Differentially centrifuged virus suspensions, containing 5.0 x 10⁸ to 2.0 x 10⁹ TCID₅₀/ml, were injected undiluted or emulsified with Freund's adjuvant into rabbits. The antigenic relationship between OSV, IHN virus, and SRCD virus was investigated using cross plaque neutralization tests with each antiserum versus the three viruses. Fifty percent plaque neutralization end points determined in these tests indicated that all three viruses were antigenically related, with OSV and IHN virus being indistinguishable. Differentially centrifuged, glutaraldehyde-fixed and unfixed suspensions of OSV were stained with phosphotungstic acid and examined with an electron microscope. The most numerous type of particle in fixed preparations was bullet-shaped with average dimensions of 98 x 166 mμ.. However, the most abundant type of particle in unfixed suspensions consisted of two roughly spherical (80 mμ in diameter), closely associated particles. The discrepancy between the appearance of fixed and unfixed OSV suspensions was not experimentally resolved. Title: The Oregon sockeye salmon virus : A. Biophysical biochemical characteristics B. antigenic relationship to two other salmonid viruses Author: McCain, Bruce B. The Oregon sockeye salmon virus (OSV) was isolated from diseased sockeye salmon (Oncorhynchus nerka) fingerlings in 1958 by J. L. Fryer. Experimentation performed prior to the research reported herein indicated that the OSV contained essential lipids, was 100 to 300 mμ in size, and possessed RNA (presumptively identified by 5-bromodeoxyuridine treatment of OSV-infected cell cultures). In the present investigation, OSV was propagated in one of two cell lines derived from the embryonic tissues of either sockeye or chinook (O. tshawytscha) salmon. Infectious cell culture medium was purified by differential centrifugation alone, or in combination with RNase and DNase treatment, and rate-zonal sucrose gradient centrifugation. OSV suspensions had a propensity for forming viral aggregates during differential centrifugation, presumably caused by pelleting virions in the presence of host cell debris and serum proteins. Partially purified virus suspensions were fractionated into four visible bands by rate-zonal or isopycnic sucrose gradient centrifugation. Most virus infectivity was detected in two closely associated bands in the middle of the gradient. Evidence suggested that the more dense, faster sedimenting band contained infectious virus and the other band was composed of incomplete, noninfectious virus particles. The sucrose density of the virus band was determined to be 1.16 g/cm³. The two other visible bands, one above and one below the presumably heterogeneous virus band, were considered to represent nonviral material complexed with varying amounts of virus. Large amounts of virus infectivity were lost either during sucrose gradient centrifugation or when sucrose concentrations were reduced in gradient fractions by dilution and/or dialysis. Purified suspensions of OSV were treated with hot perchloric acid in order to extract viral nucleic acid. RNA and DNA concentrations in the extracts were estimated with the orcinol and diphenylamine tests. Concentrations of RNA were at least 14 times higher than those of DNA. Viral nucleic acid was also extracted from purified ³²P-labeled OSV suspensions by the phenol method at 4°C. Spectral properties of the resulting nucleic acid solutions indicated that they contained relatively large amounts of protein. Viral nuclei acid formed a single band at densities of 1.58 to 1.59 g/cm³ when subjected to isopycnic cesium sulfate gradient centrifugation. Rate-zonal glycerol gradient centrifugation of ³²P-OSV nucleic acid resulted in the formation of a diffuse band of radioactivity with its peak at 26 S and a pronounced shoulder at 37 S. RNase treatment of aliquots from glycerol gradient fractions reduced all trichloroacetic acid-precipitable ³²P-radioactivity by 85 to 97%. Anion exchange chromatography of alkaline-hydrolyzed ³²P-viral nucleic acid was used to determine its base composition. Percentage base compositions were cytidylic acid, 25.8 ± 0.6%; adenylic acid, 23.0 ± 0.8%; uridylic acid, 27.7 ± 0.6%; and guanylic acid, 23.4 ± 0.4%. The fore-mentioned experimental data demonstrate that the OSV virion contains single-stranded RNA. Rabbit-immune sera were produced against OSV, infectious hematopoietic necrosis (IHN) virus, and Sacramento River chinook disease (SRCD) virus. The latter two viruses were isolated from diseased sockeye and chinook salmon, respectively. Differentially centrifuged virus suspensions, containing 5.0 x 10⁸ to 2.0 x 10⁹ TCID₅₀/ml, were injected undiluted or emulsified with Freund's adjuvant into rabbits. The antigenic relationship between OSV, IHN virus, and SRCD virus was investigated using cross plaque neutralization tests with each antiserum versus the three viruses. Fifty percent plaque neutralization end points determined in these tests indicated that all three viruses were antigenically related, with OSV and IHN virus being indistinguishable. Differentially centrifuged, glutaraldehyde-fixed and unfixed suspensions of OSV were stained with phosphotungstic acid and examined with an electron microscope. The most numerous type of particle in fixed preparations was bullet-shaped with average dimensions of 98 x 166 mμ.. However, the most abundant type of particle in unfixed suspensions consisted of two roughly spherical (80 mμ in diameter), closely associated particles. The discrepancy between the appearance of fixed and unfixed OSV suspensions was not experimentally resolved. Close

• 5663. [Article] Resilience of large river basins : applying social-ecological systems theory, conflict management, and collaboration on the Mekong and Columbia Basins

  River basins provide essential services for both humans and ecosystems. Understanding the connections between ecosystems and society and their function has been at the heart of resilience studies and has ...

  Citation × Citation Citation Abstract Copy Title: Resilience of large river basins : applying social-ecological systems theory, conflict management, and collaboration on the Mekong and Columbia Basins Author: MacQuarrie, Patrick R. River basins provide essential services for both humans and ecosystems. Understanding the connections between ecosystems and society and their function has been at the heart of resilience studies and has become an increasing important endeavor in research and practice. In this dissertation, I define basin resilience as a river basin system's capacity to absorb, manage, and adapt to biophysical, social-economic, and political changes (or stressors) while still maintaining its essential structure, feedbacks, and functional integrity. I address the question of resilience, scale, and development in the Mekong and Columbia River Basins. This dissertation answers the following questions: 1) is systems theory an appropriate model to evaluate basin resilience, 2) is the Mekong Basin resilient, 3) are the Mekong and Columbia River Basins resilient across multiple scales, 4) can conflict management and collaborative learning enhance resilience, 5) can a resilience framework be used for basin comparisons, and 6) what lessons can the Mekong basin take from rapid development in the Columbia basin? In Chapter 2, I create and apply a social-ecological systems (SES) model of the Mekong River Basin to assess resilience at sub-basin (provincial), watershed (national), and basin (regional) scales. Feedbacks, thresholds, vulnerability, and adaptive capacity are determined and used as inputs into an overall basin resilience assessment. Drawing upon field work done in the Mekong Basin, Chapter 3 uses Conflict Management and Collaborative Learning processes to address resilience weaknesses across multiple scales in the Mekong Basin. Chapter 4 uses the basin resilience framework to compare the Mekong and Columbia Basins against physical characteristics, development rate, conflict and cooperation, and institutional responses to development projects. In this dissertation I find the Mekong has medium-low basin resilience and that scale is a critical determinant in basin resilience assessments. I find that in this study, vulnerability is inversely proportional to resilience, and low resilience at one scale, for example fisheries in the Tonle Sap Lake in Cambodia, decreases resilience for the entire basin. I find that Cambodia and Lao PDR are the least resilience and Thailand the most resilient countries in the Mekong Basin – Thailand more resilient in some sectors than the Mekong River Commission (MRC). I find that the MRC's conflict management strategy is hampered by a restrictive mandate and weakness in capacity building at tributary and national scales but that Collaborative Learning processes are effective in enhancing resilience at the sub-basin scale. Finally, I demonstrate through the basin comparison that the Mekong has a highly resilient biophysical system and traditionally a resilient institutional system however, the proposed rate of development is unsustainable with trends indicating a significant erosion of resilience. I find the Columbia Basin lacking resilience in fishing, hydropower, and water quality – sectors mitigating the effects of development in the Columbia Basin, manifesting as overall negative trends in cooperation. However, the Columbia shows signs of increasing cooperation due recent inclusion of Tribal Nations in water management. Flexible and inclusive institutional responses to water resource development challenges, in the Mekong to rapid development on the mainstream and in the Columbia to negotiations over renewal of the Columbia River Treaty, are key determinants to whether or not each basin can halt the current negative trends and strengthen basin resilience to face the challenges now and those coming in the future. Title: Resilience of large river basins : applying social-ecological systems theory, conflict management, and collaboration on the Mekong and Columbia Basins Author: MacQuarrie, Patrick R. River basins provide essential services for both humans and ecosystems. Understanding the connections between ecosystems and society and their function has been at the heart of resilience studies and has become an increasing important endeavor in research and practice. In this dissertation, I define basin resilience as a river basin system's capacity to absorb, manage, and adapt to biophysical, social-economic, and political changes (or stressors) while still maintaining its essential structure, feedbacks, and functional integrity. I address the question of resilience, scale, and development in the Mekong and Columbia River Basins. This dissertation answers the following questions: 1) is systems theory an appropriate model to evaluate basin resilience, 2) is the Mekong Basin resilient, 3) are the Mekong and Columbia River Basins resilient across multiple scales, 4) can conflict management and collaborative learning enhance resilience, 5) can a resilience framework be used for basin comparisons, and 6) what lessons can the Mekong basin take from rapid development in the Columbia basin? In Chapter 2, I create and apply a social-ecological systems (SES) model of the Mekong River Basin to assess resilience at sub-basin (provincial), watershed (national), and basin (regional) scales. Feedbacks, thresholds, vulnerability, and adaptive capacity are determined and used as inputs into an overall basin resilience assessment. Drawing upon field work done in the Mekong Basin, Chapter 3 uses Conflict Management and Collaborative Learning processes to address resilience weaknesses across multiple scales in the Mekong Basin. Chapter 4 uses the basin resilience framework to compare the Mekong and Columbia Basins against physical characteristics, development rate, conflict and cooperation, and institutional responses to development projects. In this dissertation I find the Mekong has medium-low basin resilience and that scale is a critical determinant in basin resilience assessments. I find that in this study, vulnerability is inversely proportional to resilience, and low resilience at one scale, for example fisheries in the Tonle Sap Lake in Cambodia, decreases resilience for the entire basin. I find that Cambodia and Lao PDR are the least resilience and Thailand the most resilient countries in the Mekong Basin – Thailand more resilient in some sectors than the Mekong River Commission (MRC). I find that the MRC's conflict management strategy is hampered by a restrictive mandate and weakness in capacity building at tributary and national scales but that Collaborative Learning processes are effective in enhancing resilience at the sub-basin scale. Finally, I demonstrate through the basin comparison that the Mekong has a highly resilient biophysical system and traditionally a resilient institutional system however, the proposed rate of development is unsustainable with trends indicating a significant erosion of resilience. I find the Columbia Basin lacking resilience in fishing, hydropower, and water quality – sectors mitigating the effects of development in the Columbia Basin, manifesting as overall negative trends in cooperation. However, the Columbia shows signs of increasing cooperation due recent inclusion of Tribal Nations in water management. Flexible and inclusive institutional responses to water resource development challenges, in the Mekong to rapid development on the mainstream and in the Columbia to negotiations over renewal of the Columbia River Treaty, are key determinants to whether or not each basin can halt the current negative trends and strengthen basin resilience to face the challenges now and those coming in the future. Close

• 5664. [Article] Passage, migration behavior, and autoecology of adult Pacific lamprey at Winchester Dam and within the North Umpqua River Basin, Oregon, USA

  The extensive reduction in adult Pacific lamprey (Entosphenus tridentatus) counts at many hydroelectric dams in the northwestern USA signals a substantial decline in lamprey numbers across the entire region ...

  Citation × Citation Citation Abstract Copy Title: Passage, migration behavior, and autoecology of adult Pacific lamprey at Winchester Dam and within the North Umpqua River Basin, Oregon, USA Author: Lampman, Ralph Tatsuo The extensive reduction in adult Pacific lamprey (Entosphenus tridentatus) counts at many hydroelectric dams in the northwestern USA signals a substantial decline in lamprey numbers across the entire region in the past 40 to 50 years. Among the many potential causes of this decline, obstruction of migration routes has likely played a substantial role. Within the North Umpqua River basin in southwest Oregon, USA, I focused on the following three research goals: 1) to describe the passage efficiency and migration routes of adult Pacific lamprey at Winchester Dam; 2) to evaluate the seasonal movement patterns of adult Pacific lamprey and their use of holding habitat at Winchester Dam in relation to temperature conditions; and 3) to portray the diversity of upstream migratory behaviors of adult Pacific lamprey and the environmental factors that influence these behaviors. This radio telemetry study was conducted between March 2009 and August 2011 with a combination of fixed stations and manual tracking. Passage efficiency was low in both years (8% and 19%, respectively), and all tagged lamprey that successfully passed the dam used routes other than the fish ladder. Lamprey that migrated early within the run and those with relatively small tags had higher passage rates and traveled further than the other groups of lamprey. Lamprey released above of the dam or those that passed the dam on their own distributed themselves widely in the upstream environment, suggesting that the dam deterred their upstream migration. Using mark-recapture data for the two years, the adult Pacific lamprey population upstream of Winchester Dam was estimated at 960 (95% C.I. [188, 4760]) in 2009 and 556 (95% C.I. [110, 2798]) in 2010, which was considerably lower than historical counts at the dam (between 14,532-46,785 in 1965-1971). Most tagged lamprey that did not pass the dam remained at the base of the dam at the end of the summer migration (63% in 2009 and 67% in 2010). Types of habitat most frequently used by lamprey downstream from the dam included the dam surface (wooden structures with crevices), interface zones between fast and slow water, and highway bridge pilings. The lamprey movement changed considerably between August and September, and the frequency of movements decreased sharply during this period. Tagged lamprey were detected using thermal refuges immediately downstream of the dam that were 0.4 to 2.8 C° colder than the mean river temperature at the dam, and this temperature differential increased as the season progressed. Lamprey may be seeking overwintering habitat associated with hyporheic exchange flows at the dam towards the end of the summer season after their display of heightened activity early in the summer. Ninety-five percent of the overall upstream migration took place during the first spring/summer period, and only small-scale upstream movements were observed during the winter and second spring/summer (4% and 1%, respectively). The rate of upstream migration (median) was the fastest during the initial migration phase and was 1.9 km/day (ranging from 0.3 to 11.0 km/day) for tagged lamprey released above Winchester Dam. During winter, 71% of the lamprey remained in the same location where they initiated holding. Multiple regression analysis indicated that the total upstream distance traveled by individual lamprey was most strongly related to presence/absence of Winchester Dam, relative tag size, and water temperature and photoperiod conditions at release. The presence of Winchester Dam, large relative tag size, and high water temperature / short photoperiod conditions at release significantly reduced upstream migration distance. Title: Passage, migration behavior, and autoecology of adult Pacific lamprey at Winchester Dam and within the North Umpqua River Basin, Oregon, USA Author: Lampman, Ralph Tatsuo The extensive reduction in adult Pacific lamprey (Entosphenus tridentatus) counts at many hydroelectric dams in the northwestern USA signals a substantial decline in lamprey numbers across the entire region in the past 40 to 50 years. Among the many potential causes of this decline, obstruction of migration routes has likely played a substantial role. Within the North Umpqua River basin in southwest Oregon, USA, I focused on the following three research goals: 1) to describe the passage efficiency and migration routes of adult Pacific lamprey at Winchester Dam; 2) to evaluate the seasonal movement patterns of adult Pacific lamprey and their use of holding habitat at Winchester Dam in relation to temperature conditions; and 3) to portray the diversity of upstream migratory behaviors of adult Pacific lamprey and the environmental factors that influence these behaviors. This radio telemetry study was conducted between March 2009 and August 2011 with a combination of fixed stations and manual tracking. Passage efficiency was low in both years (8% and 19%, respectively), and all tagged lamprey that successfully passed the dam used routes other than the fish ladder. Lamprey that migrated early within the run and those with relatively small tags had higher passage rates and traveled further than the other groups of lamprey. Lamprey released above of the dam or those that passed the dam on their own distributed themselves widely in the upstream environment, suggesting that the dam deterred their upstream migration. Using mark-recapture data for the two years, the adult Pacific lamprey population upstream of Winchester Dam was estimated at 960 (95% C.I. [188, 4760]) in 2009 and 556 (95% C.I. [110, 2798]) in 2010, which was considerably lower than historical counts at the dam (between 14,532-46,785 in 1965-1971). Most tagged lamprey that did not pass the dam remained at the base of the dam at the end of the summer migration (63% in 2009 and 67% in 2010). Types of habitat most frequently used by lamprey downstream from the dam included the dam surface (wooden structures with crevices), interface zones between fast and slow water, and highway bridge pilings. The lamprey movement changed considerably between August and September, and the frequency of movements decreased sharply during this period. Tagged lamprey were detected using thermal refuges immediately downstream of the dam that were 0.4 to 2.8 C° colder than the mean river temperature at the dam, and this temperature differential increased as the season progressed. Lamprey may be seeking overwintering habitat associated with hyporheic exchange flows at the dam towards the end of the summer season after their display of heightened activity early in the summer. Ninety-five percent of the overall upstream migration took place during the first spring/summer period, and only small-scale upstream movements were observed during the winter and second spring/summer (4% and 1%, respectively). The rate of upstream migration (median) was the fastest during the initial migration phase and was 1.9 km/day (ranging from 0.3 to 11.0 km/day) for tagged lamprey released above Winchester Dam. During winter, 71% of the lamprey remained in the same location where they initiated holding. Multiple regression analysis indicated that the total upstream distance traveled by individual lamprey was most strongly related to presence/absence of Winchester Dam, relative tag size, and water temperature and photoperiod conditions at release. The presence of Winchester Dam, large relative tag size, and high water temperature / short photoperiod conditions at release significantly reduced upstream migration distance. Close

• 5665. [Article] Restoration of native upland prairies: Habitat for Fender’s blue butterfly (Icaricia icarioides fenderi)

  Our project goal is to promote the abundance of the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) by recreating upland prairie habitat in former agricultural land at Finley National ...

  Citation × Citation Citation Abstract Copy Title: Restoration of native upland prairies: Habitat for Fender’s blue butterfly (Icaricia icarioides fenderi) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Our project goal is to promote the abundance of the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) by recreating upland prairie habitat in former agricultural land at Finley National Wildlife Refuge, Corvallis, Oregon. To achieve this goal we initiated the following three studies. Study One: Experimental Investigation on the Effectiveness of Restoration Treatments Our approach was to set up experimental field plots in a former agricultural field into which we sowed seeds of native grasses and dicots in the fall for two years, 2003 and 2004. Objective one: Investigate the effect of carbon banding on abundance of sowed native species and non-native species. Carbon banding is a treatment used by Willamette Valley grass seed farmers to promote seedling establishment of agricultural grasses and inhibit seedling establishment of weeds. Objective two: Investigate the effect of the sowing sequence of native dicot and grass species on the abundance and species richness of the sowed species. Our experiments were designed to test the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. Objective three: Investigate the effect of the sowing sequence of the native dicot and grass species on the abundance of non-native species. Study Two: Monoculture Sowing of Native Species Compare the cover of non-native species and the cover of native species one and two years after sowing native species in monocultures. Study Three: Buffer Sowing of Native Grasses Monitor the abundance of the native grasses sowed in the buffer areas outside the experimental plots. Carbon banding had no significant effect on cover of non-native species or on cover and species richness of sowed native dicots or grasses after both the first and second growing seasons. However, carbon banding tended to reduce the cover of the annual Clarkia rhomboidea after the first growing season. Our results supported the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. The sowing sequences tested did not affect cover and species richness of grasses but did affect cover and species richness of dicot species. Both dicot cover and dicot species richness were greater when sowed a year ahead of the grasses. Eriophyllum lanatum had significantly greater cover when sowed a year before the grasses. Average cover of sowed dicots was significantly greater when dicots were sowed with grasses compared to when dicots were sowed into a year-old stand of grasses. In particular, Madia gracilis and Prunella vulgaris var. lanceolata had less cover when sowed into the existing stand of grass. Species richness of all native species (grasses + dicots) was significantly less when dicots were sowed into a year-old stand of grasses. However, total cover and species richness of sowed native species (grasses + dicots) were not significantly different whether dicots were sowed a year ahead of the grasses or whether dicots and grasses were sowed together. Average cover of sowed native dicots after two years was always greater than the cover of sowed native grasses except when dicots were sowed a year after the grasses. After two growing seasons, non-native cover did not significantly vary among the three sowing sequences of sowing grasses and dicots at the same time, sowing grasses into existing dicot vegetation, and sowing grasses into existing dicot vegetation. The first year after sowing the monocultures (Study two), Collinsia grandiflora had the highest cover, greatly surpassing the next top performers, Sanguisorba occidentalis and Madia gracilis, all of which are annual species. In general, the cover of individual species sowed in monocultures decreased the second year after sowing. Only seven species, all of which were perennials, out of the 26 sowed species increased in cover. Two of these species Eriophyllum lanatum and Prunella vulgaris var. lanceolata were the top performers for 2005, but their cover did not reach the levels of the top performers in 2004. Title: Restoration of native upland prairies: Habitat for Fender’s blue butterfly (Icaricia icarioides fenderi) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Our project goal is to promote the abundance of the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) by recreating upland prairie habitat in former agricultural land at Finley National Wildlife Refuge, Corvallis, Oregon. To achieve this goal we initiated the following three studies. Study One: Experimental Investigation on the Effectiveness of Restoration Treatments Our approach was to set up experimental field plots in a former agricultural field into which we sowed seeds of native grasses and dicots in the fall for two years, 2003 and 2004. Objective one: Investigate the effect of carbon banding on abundance of sowed native species and non-native species. Carbon banding is a treatment used by Willamette Valley grass seed farmers to promote seedling establishment of agricultural grasses and inhibit seedling establishment of weeds. Objective two: Investigate the effect of the sowing sequence of native dicot and grass species on the abundance and species richness of the sowed species. Our experiments were designed to test the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. Objective three: Investigate the effect of the sowing sequence of the native dicot and grass species on the abundance of non-native species. Study Two: Monoculture Sowing of Native Species Compare the cover of non-native species and the cover of native species one and two years after sowing native species in monocultures. Study Three: Buffer Sowing of Native Grasses Monitor the abundance of the native grasses sowed in the buffer areas outside the experimental plots. Carbon banding had no significant effect on cover of non-native species or on cover and species richness of sowed native dicots or grasses after both the first and second growing seasons. However, carbon banding tended to reduce the cover of the annual Clarkia rhomboidea after the first growing season. Our results supported the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. The sowing sequences tested did not affect cover and species richness of grasses but did affect cover and species richness of dicot species. Both dicot cover and dicot species richness were greater when sowed a year ahead of the grasses. Eriophyllum lanatum had significantly greater cover when sowed a year before the grasses. Average cover of sowed dicots was significantly greater when dicots were sowed with grasses compared to when dicots were sowed into a year-old stand of grasses. In particular, Madia gracilis and Prunella vulgaris var. lanceolata had less cover when sowed into the existing stand of grass. Species richness of all native species (grasses + dicots) was significantly less when dicots were sowed into a year-old stand of grasses. However, total cover and species richness of sowed native species (grasses + dicots) were not significantly different whether dicots were sowed a year ahead of the grasses or whether dicots and grasses were sowed together. Average cover of sowed native dicots after two years was always greater than the cover of sowed native grasses except when dicots were sowed a year after the grasses. After two growing seasons, non-native cover did not significantly vary among the three sowing sequences of sowing grasses and dicots at the same time, sowing grasses into existing dicot vegetation, and sowing grasses into existing dicot vegetation. The first year after sowing the monocultures (Study two), Collinsia grandiflora had the highest cover, greatly surpassing the next top performers, Sanguisorba occidentalis and Madia gracilis, all of which are annual species. In general, the cover of individual species sowed in monocultures decreased the second year after sowing. Only seven species, all of which were perennials, out of the 26 sowed species increased in cover. Two of these species Eriophyllum lanatum and Prunella vulgaris var. lanceolata were the top performers for 2005, but their cover did not reach the levels of the top performers in 2004. Close

• 5666. [Article] Nest fidelity and colony dynamics of Caspian terns nesting at East Sand Island, Columbia River Estuary, Oregon, USA

  Fidelity to breeding sites in colonial birds is an adaptive trait thought to have evolved to enhance reproductive success by reducing search time for breeding habitat, allowing earlier nest initiation, ...

  Citation × Citation Citation Abstract Copy Title: Nest fidelity and colony dynamics of Caspian terns nesting at East Sand Island, Columbia River Estuary, Oregon, USA Author: Collar, Stefanie Fidelity to breeding sites in colonial birds is an adaptive trait thought to have evolved to enhance reproductive success by reducing search time for breeding habitat, allowing earlier nest initiation, facilitating mate retention, and reducing uncertainty of predator presence and food availability. Studying a seabird that has evolved relatively low colony fidelity, such as the Caspian tern, allowed me to explore the influence of stable nesting habitat on fidelity and nest site selection. The Caspian tern (Hydroprogne caspia) breeding colony on East Sand Island (ESI) in the Columbia River estuary is the largest colony of its kind in the world. This colony has experienced a decade of declining nesting success, culminating with the failure of the colony to produce any young in 2011. The objective of my study was to understand the dynamics of this Caspian tern super-colony by investigating the actions of breeding individuals over two seasons, as well as the behavior of the colony as a whole from 2001-2011. I was interested in (1) the degree of nest site fidelity exhibited by breeding terns in successive years and its relationship to reproductive success, and (2) how the interaction of top-down and bottom-up forces influenced average nesting success across the entire colony, and caused the observed trends in nesting success at the East Sand Island colony from 2001 to 2011. My study investigated the potential influence of bottom-up and top-down drivers for the declining productivity at this once thriving colony of Caspian terns. I used sophisticated surveying equipment to test for nest site fidelity and group adherence between two consecutive breeding seasons for 80 Caspian terns marked with field readable leg bands. Available bare sand nesting habitat at this colony site declined steeply between the two years, displacing some focal individuals from their previously held nest territories. Terns whose former nest site was no longer in suitable habitat had twice the inter-annual distance between nests when compared with terns whose former nest site was still in suitable habitat. There was a negative association between inter-annual distance between nests and the number of neighbors retained from the previous year. Displaced terns retained few, if any, neighbors, indicating that group adherence by nesting terns was largely a result of individual philopatry to nesting areas within the colony, rather than adherence to neighboring nesting pairs. There was a tendency for displaced terns to nest in closer proximity to the edge of the colony, and to have nesting attempts that ended earlier than did non-displaced terns. After all nesting attempts failed during year 2 of the study, terns displaced from year 1 nest sites paradoxically exhibited higher fidelity to the colony site after colony failure in year 2 than terns that retained their year 1 nesting area. Failure of the previous nesting attempt and the novelty of the nest site and its neighbors, factors that should have resulted in low philopatry, were out-weighed by the scarcity of suitable alternative nesting habitat for Caspian terns within the region. I also investigated the potential influence of bottom-up and top-down drivers for the declining productivity at this once thriving colony of Caspian terns. Since 2001 the decline in reproductive success of Caspian terns at ESI has been associated with a significant increase in average river discharge during May and June. I also found a significant increase in kleptoparasitism rates of terns by glaucous-winged/western gulls (Larus glaucescens x L. occidentalis) since 2001, and a significant negative relationship between average annual rates of gull kleptoparasitism and Caspian tern nesting success at ESI. There has also been a significant increase in disturbance rates by bald eagles (Haliaeetus leucocephalus) during June for terns nesting at the ESI colony, and eagle disturbance rates were positively associated with May river discharge. The abundance of forage fish for terns in the estuary was inversely related to river discharge, which also influences the reliance of tern nest predators on the tern colony as a food source, resulting in increased disturbance and decreased reproductive success at the tern colony. Although correlational, our results support the hypothesis that the decline in Caspian tern nesting success at this large estuarine colony is primarily initiated by bottom-up factors, both as they directly affect tern productivity through the food supply, and indirectly as they affect the alternative food supply of potential tern nest predators. Title: Nest fidelity and colony dynamics of Caspian terns nesting at East Sand Island, Columbia River Estuary, Oregon, USA Author: Collar, Stefanie Fidelity to breeding sites in colonial birds is an adaptive trait thought to have evolved to enhance reproductive success by reducing search time for breeding habitat, allowing earlier nest initiation, facilitating mate retention, and reducing uncertainty of predator presence and food availability. Studying a seabird that has evolved relatively low colony fidelity, such as the Caspian tern, allowed me to explore the influence of stable nesting habitat on fidelity and nest site selection. The Caspian tern (Hydroprogne caspia) breeding colony on East Sand Island (ESI) in the Columbia River estuary is the largest colony of its kind in the world. This colony has experienced a decade of declining nesting success, culminating with the failure of the colony to produce any young in 2011. The objective of my study was to understand the dynamics of this Caspian tern super-colony by investigating the actions of breeding individuals over two seasons, as well as the behavior of the colony as a whole from 2001-2011. I was interested in (1) the degree of nest site fidelity exhibited by breeding terns in successive years and its relationship to reproductive success, and (2) how the interaction of top-down and bottom-up forces influenced average nesting success across the entire colony, and caused the observed trends in nesting success at the East Sand Island colony from 2001 to 2011. My study investigated the potential influence of bottom-up and top-down drivers for the declining productivity at this once thriving colony of Caspian terns. I used sophisticated surveying equipment to test for nest site fidelity and group adherence between two consecutive breeding seasons for 80 Caspian terns marked with field readable leg bands. Available bare sand nesting habitat at this colony site declined steeply between the two years, displacing some focal individuals from their previously held nest territories. Terns whose former nest site was no longer in suitable habitat had twice the inter-annual distance between nests when compared with terns whose former nest site was still in suitable habitat. There was a negative association between inter-annual distance between nests and the number of neighbors retained from the previous year. Displaced terns retained few, if any, neighbors, indicating that group adherence by nesting terns was largely a result of individual philopatry to nesting areas within the colony, rather than adherence to neighboring nesting pairs. There was a tendency for displaced terns to nest in closer proximity to the edge of the colony, and to have nesting attempts that ended earlier than did non-displaced terns. After all nesting attempts failed during year 2 of the study, terns displaced from year 1 nest sites paradoxically exhibited higher fidelity to the colony site after colony failure in year 2 than terns that retained their year 1 nesting area. Failure of the previous nesting attempt and the novelty of the nest site and its neighbors, factors that should have resulted in low philopatry, were out-weighed by the scarcity of suitable alternative nesting habitat for Caspian terns within the region. I also investigated the potential influence of bottom-up and top-down drivers for the declining productivity at this once thriving colony of Caspian terns. Since 2001 the decline in reproductive success of Caspian terns at ESI has been associated with a significant increase in average river discharge during May and June. I also found a significant increase in kleptoparasitism rates of terns by glaucous-winged/western gulls (Larus glaucescens x L. occidentalis) since 2001, and a significant negative relationship between average annual rates of gull kleptoparasitism and Caspian tern nesting success at ESI. There has also been a significant increase in disturbance rates by bald eagles (Haliaeetus leucocephalus) during June for terns nesting at the ESI colony, and eagle disturbance rates were positively associated with May river discharge. The abundance of forage fish for terns in the estuary was inversely related to river discharge, which also influences the reliance of tern nest predators on the tern colony as a food source, resulting in increased disturbance and decreased reproductive success at the tern colony. Although correlational, our results support the hypothesis that the decline in Caspian tern nesting success at this large estuarine colony is primarily initiated by bottom-up factors, both as they directly affect tern productivity through the food supply, and indirectly as they affect the alternative food supply of potential tern nest predators. Close

• 5667. [Article] Drought, dispersal, and community dynamics in arid-land streams

  Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional ...

  Citation × Citation Citation Abstract Copy Title: Drought, dispersal, and community dynamics in arid-land streams Author: Bogan, Michael T. Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional processes; these processes act as filters that reduce the regional species pool down to the observed local community. In stream ecosystems, the natural flow regime (including the timing, magnitude, and duration of high and low flow events) is widely recognized as a primary regulator of local diversity and community composition. This is especially true in aridland streams, where low- and zero-flow events can occur frequently and for extended periods of time (months to years). Additionally, wetted habitat patches in arid-land stream networks are often fragmented within and among stream networks. Thus dispersal between isolated aquatic patches may also play a large role in regulating local communities. In my dissertation, I explored the roles that drought, dispersal, and local habitat factors play in structuring arid-land stream communities. I examined the impact of flow permanence and seasonal variation in flow and other abiotic factors on aquatic communities at both fine spatial scales over a long time period (8 years; Chapter 2) and at a broad spatial scale over a shorter time period (1-2 years; Chapter 4). Additionally, I quantified aquatic invertebrate aerial dispersal over moderate spatial scales (≤ 0.5 km) by conducting a colonization experiment using artificial stream pools placed along and inland from two arid-land streams (Chapter 4). Finally, I examined the roles of spatial isolation, microhabitat type, and local abiotic and biotic factors in structuring aquatic communities in freshwater oases scattered across one of the most arid regions of North America, the southern Sonoran Desert (Chapter 5). In Chapter 2, I found that severe drought caused an unprecedented drying event in isolated perennial stream pools, and that several additional drying events occurred over the following four years. This transition to intermittent flow caused the extirpation of several large, long-lived species with low dispersal abilities (including the top predator) and drove the local community into an alternative state. In the colonization experiment described in Chapter 3, I found that several arid-land stream invertebrate taxa disperse widely and frequently. The widespread dispersers identified by this experiment included several of the earliest colonist taxa observed following the severe drought described in Chapter 2. Other taxa, though, only dispersed overland after receiving an environmental cue (rainfall) or preferentially dispersed along stream corridors. In Chapter 4, where I examined invertebrate community structure across a large network of well-connected intermittent and perennial reaches, I found low diversity in intermittent reaches, regardless of their connectivity to diverse upstream perennial reaches. These species-poor, intermittent communities were composed of a unique suite of species with lifehistory adaptations that conferred desiccation resistance, including extended egg and larval diapause stages. The short flow duration of intermittent reaches (<100 days) likely precluded upstream perennial taxa from establishing populations in downstream intermittent reaches before drying occurred, while the relative predictability of flow timing (Dec-Apr) likely allowed for a small number of species to develop appropriate life-history traits (e.g., diapause stage, rapid development time) to exploit these temporally-fleeting habitats. In Chapter 5, I found over 220 species of aquatic animals (including ≥ 5 undescribed species) in the 19 desert oases that were sampled across the southern Sonoran Desert. Local community composition in these oases was strongly driven by microhabitat type. Additionally, native aquatic species richness and abundance in these oases were significantly reduced by the introduction of tilapia, an exotic fish species. The threats to arid-land streams presented by increased drought severity, anthropogenic water withdrawals, and local habitat degradation (e.g., introduced species, unmanaged recreational use) are grave across the southwestern US and northwestern Mexico. I hope that in addition to furthering our understanding of ecological processes in arid-land streams, this dissertation makes a small contribution towards the efforts to preserve these habitats. Title: Drought, dispersal, and community dynamics in arid-land streams Author: Bogan, Michael T. Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional processes; these processes act as filters that reduce the regional species pool down to the observed local community. In stream ecosystems, the natural flow regime (including the timing, magnitude, and duration of high and low flow events) is widely recognized as a primary regulator of local diversity and community composition. This is especially true in aridland streams, where low- and zero-flow events can occur frequently and for extended periods of time (months to years). Additionally, wetted habitat patches in arid-land stream networks are often fragmented within and among stream networks. Thus dispersal between isolated aquatic patches may also play a large role in regulating local communities. In my dissertation, I explored the roles that drought, dispersal, and local habitat factors play in structuring arid-land stream communities. I examined the impact of flow permanence and seasonal variation in flow and other abiotic factors on aquatic communities at both fine spatial scales over a long time period (8 years; Chapter 2) and at a broad spatial scale over a shorter time period (1-2 years; Chapter 4). Additionally, I quantified aquatic invertebrate aerial dispersal over moderate spatial scales (≤ 0.5 km) by conducting a colonization experiment using artificial stream pools placed along and inland from two arid-land streams (Chapter 4). Finally, I examined the roles of spatial isolation, microhabitat type, and local abiotic and biotic factors in structuring aquatic communities in freshwater oases scattered across one of the most arid regions of North America, the southern Sonoran Desert (Chapter 5). In Chapter 2, I found that severe drought caused an unprecedented drying event in isolated perennial stream pools, and that several additional drying events occurred over the following four years. This transition to intermittent flow caused the extirpation of several large, long-lived species with low dispersal abilities (including the top predator) and drove the local community into an alternative state. In the colonization experiment described in Chapter 3, I found that several arid-land stream invertebrate taxa disperse widely and frequently. The widespread dispersers identified by this experiment included several of the earliest colonist taxa observed following the severe drought described in Chapter 2. Other taxa, though, only dispersed overland after receiving an environmental cue (rainfall) or preferentially dispersed along stream corridors. In Chapter 4, where I examined invertebrate community structure across a large network of well-connected intermittent and perennial reaches, I found low diversity in intermittent reaches, regardless of their connectivity to diverse upstream perennial reaches. These species-poor, intermittent communities were composed of a unique suite of species with lifehistory adaptations that conferred desiccation resistance, including extended egg and larval diapause stages. The short flow duration of intermittent reaches (<100 days) likely precluded upstream perennial taxa from establishing populations in downstream intermittent reaches before drying occurred, while the relative predictability of flow timing (Dec-Apr) likely allowed for a small number of species to develop appropriate life-history traits (e.g., diapause stage, rapid development time) to exploit these temporally-fleeting habitats. In Chapter 5, I found over 220 species of aquatic animals (including ≥ 5 undescribed species) in the 19 desert oases that were sampled across the southern Sonoran Desert. Local community composition in these oases was strongly driven by microhabitat type. Additionally, native aquatic species richness and abundance in these oases were significantly reduced by the introduction of tilapia, an exotic fish species. The threats to arid-land streams presented by increased drought severity, anthropogenic water withdrawals, and local habitat degradation (e.g., introduced species, unmanaged recreational use) are grave across the southwestern US and northwestern Mexico. I hope that in addition to furthering our understanding of ecological processes in arid-land streams, this dissertation makes a small contribution towards the efforts to preserve these habitats. Close

• 5668. [Article] Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils

  Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially ...

  Citation × Citation Citation Abstract Copy Title: Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils Author: Sepaskhah, Ali Reza Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially utilize waste heat may include home heating and cooling, greenhouses, animal enclosures, open basins for single cell protein production and fish farming, and open field soil warming. A subsurface irrigation-soil warming system utilizing waste heat was analyzed in this study. Thermal power plant condenser cooling water pumped through buried porous pipes was considered as a heat and water source for soil heating and subsurface irrigation. Energy is transferred from the heat source to the surrounding soil, warming it above its natural temperature. In addition, water seeping from the porous pipe prevents drying around the heat source and supplies the plant roots throughout the soil profile while avoiding the large evaporation losses at the soil surface associated with surface irrigation methods. Experiments were conducted in the laboratory to study this system. Soil was packed in containers 48 cm deep, 40 cm wide, and 4 cm thick. A heat source consisting of a copper covered electrical resistance wire was placed against one side of the box at a depth of 32 cm. A water source consisting of a porous tube was placed 2 cm above the heat source. The contained soil slab thus represented a subsurface soil warming and irrigation system with heat and water sources at depths of 32 and 30 cm respectively and a 77 cm spacing. A series of experiments was conducted with heat source temperatures of 29, 36, and 44 C, and surface heat load cycles with maxima of 0, 13, 52, and 117 watts. These experiments were repeated for Quincy, Cloquato, and Chehalis soils. The box filled with soil was saturated with water and then drained. Experiments were initiated by energizing the heat source. Temperature distributions throughout the soil profile and rates of energy dissipation were measured. Water application rates required to maintain a constant soil water content were obtained. In each experiment, water was applied at such a rate that the water content at a point near the heat source, monitored with a gamma ray attenuation system, remained constant. Apparent thermal conductivities of Quincy, Cloquato, and Chehalis soils as a function of water content were measured at 25 and 45 C by the heat probe method. The soil apparent thermal conductivity was also computed from a theoretical model based on its mineral composition, porosity, water content, and the thermal conductivity of the individual components. This model takes into account the vapor flow contribution to the apparent thermal conductivity in wet soils. Its magnitude depends on the available air-filled pore space, total porosity, and the free energy of the retained water. Predicted and experimental values of thermal conductivities showed good agreement. Soil temperature distributions were calculated using theoretical models presented in the literature. Predicted and measured isotherms showed good agreement. Energy dissipation rates as a function of soil thermal conductivity, temperature differences between heat source and soil surface, and depth and spacing of heat source were obtained. They were in agreement with those calculated from theoretical considerations. The total land area required to dissipate the waste energy from a 1000 MWe power plant operating with 34 percent efficiency was calculated for each of the three soils used in the experiments. It was found that 2841, 3714, and 4390 hectare would be required for Quincy, Cloquato, and Chehalis soils respectively. Quincy soil would require the smallest land area for this purpose because of its higher thermal conductivity. Economical and technical considerations for the installation of subsurface heating and irrigation systems require flat land close to the electrical power plant. Large areas of flat land are not always present. Subsurface irrigation replenished water lost by surface evaporation. Water use rates were obtained as a function of temperature differences between heat source and soil surface, soil type, and a range of surface heat loads. The water application rates ranged from 1.50 mm/day for Chehalis soil with a heat source temperature of 29 C in combination with the lowest surface heat load to 6.0 mm/day for Quincy soil with a heat source temperature of 44 C in combination with the highest surface heat load. These rates were adequate to prevent drying around the heat sources and supply the water needs of an actively growing crop. The effective use of this system depends on the development of suitable tubing to conduct and discharge water which could be used without clogging of the pores through which water seeps into the ground. The proposed soil warming and irrigation system does not appear to be an attractive alternative power plant cooling system. The system holds promise however as an economically attractive management system for the production of high value crops. Title: Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils Author: Sepaskhah, Ali Reza Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially utilize waste heat may include home heating and cooling, greenhouses, animal enclosures, open basins for single cell protein production and fish farming, and open field soil warming. A subsurface irrigation-soil warming system utilizing waste heat was analyzed in this study. Thermal power plant condenser cooling water pumped through buried porous pipes was considered as a heat and water source for soil heating and subsurface irrigation. Energy is transferred from the heat source to the surrounding soil, warming it above its natural temperature. In addition, water seeping from the porous pipe prevents drying around the heat source and supplies the plant roots throughout the soil profile while avoiding the large evaporation losses at the soil surface associated with surface irrigation methods. Experiments were conducted in the laboratory to study this system. Soil was packed in containers 48 cm deep, 40 cm wide, and 4 cm thick. A heat source consisting of a copper covered electrical resistance wire was placed against one side of the box at a depth of 32 cm. A water source consisting of a porous tube was placed 2 cm above the heat source. The contained soil slab thus represented a subsurface soil warming and irrigation system with heat and water sources at depths of 32 and 30 cm respectively and a 77 cm spacing. A series of experiments was conducted with heat source temperatures of 29, 36, and 44 C, and surface heat load cycles with maxima of 0, 13, 52, and 117 watts. These experiments were repeated for Quincy, Cloquato, and Chehalis soils. The box filled with soil was saturated with water and then drained. Experiments were initiated by energizing the heat source. Temperature distributions throughout the soil profile and rates of energy dissipation were measured. Water application rates required to maintain a constant soil water content were obtained. In each experiment, water was applied at such a rate that the water content at a point near the heat source, monitored with a gamma ray attenuation system, remained constant. Apparent thermal conductivities of Quincy, Cloquato, and Chehalis soils as a function of water content were measured at 25 and 45 C by the heat probe method. The soil apparent thermal conductivity was also computed from a theoretical model based on its mineral composition, porosity, water content, and the thermal conductivity of the individual components. This model takes into account the vapor flow contribution to the apparent thermal conductivity in wet soils. Its magnitude depends on the available air-filled pore space, total porosity, and the free energy of the retained water. Predicted and experimental values of thermal conductivities showed good agreement. Soil temperature distributions were calculated using theoretical models presented in the literature. Predicted and measured isotherms showed good agreement. Energy dissipation rates as a function of soil thermal conductivity, temperature differences between heat source and soil surface, and depth and spacing of heat source were obtained. They were in agreement with those calculated from theoretical considerations. The total land area required to dissipate the waste energy from a 1000 MWe power plant operating with 34 percent efficiency was calculated for each of the three soils used in the experiments. It was found that 2841, 3714, and 4390 hectare would be required for Quincy, Cloquato, and Chehalis soils respectively. Quincy soil would require the smallest land area for this purpose because of its higher thermal conductivity. Economical and technical considerations for the installation of subsurface heating and irrigation systems require flat land close to the electrical power plant. Large areas of flat land are not always present. Subsurface irrigation replenished water lost by surface evaporation. Water use rates were obtained as a function of temperature differences between heat source and soil surface, soil type, and a range of surface heat loads. The water application rates ranged from 1.50 mm/day for Chehalis soil with a heat source temperature of 29 C in combination with the lowest surface heat load to 6.0 mm/day for Quincy soil with a heat source temperature of 44 C in combination with the highest surface heat load. These rates were adequate to prevent drying around the heat sources and supply the water needs of an actively growing crop. The effective use of this system depends on the development of suitable tubing to conduct and discharge water which could be used without clogging of the pores through which water seeps into the ground. The proposed soil warming and irrigation system does not appear to be an attractive alternative power plant cooling system. The system holds promise however as an economically attractive management system for the production of high value crops. Close

• 5669. [Article] The ecology of riparian ecosystems of Northeast Oregon : shrub recovery at Meadow Creek and the structure and biomass of headwater Upper Grande Ronde ecosystems

  Riparian ecosystems play numerous and essential roles related to the quality and flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, ...

  Citation × Citation Citation Abstract Copy Title: The ecology of riparian ecosystems of Northeast Oregon : shrub recovery at Meadow Creek and the structure and biomass of headwater Upper Grande Ronde ecosystems Author: Case, Richard L. Riparian ecosystems play numerous and essential roles related to the quality and flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, these zones influence the integrity of the terrestrial as well as the entire aquatic-riverine ecosystem. Since Euro-American settlement in the West, the structure and condition of many riparian ecosystems has been significantly altered. To provide tools and an ecological perspective related to riparian restoration and management, and to document late 20th century headwater riparian structure and biomass in the Upper Grande Ronde Basin, this research project was undertaken. At Meadow Creek, the response of riparian hardwood species to the termination of livestock grazing was quantified. Regression equations were developed to predict shrub biomass. Permanently marked hardwood plants were measured annually to quantify parameters of growth (height, crown area, mainstem diameter, number of stems, biomass). Permanent belt transects on gravel bars were utilized to quantify rates of shrub establishment. Elk/deer-proof exclosures allowed the quantification of the browsing influence of wild ungulates. In 1991, initial shrub heights and densities reflected decades of grazing pressure. Mean heights of515 woody plants (14 species) was 47 cm and densities on gravel bars averaged 10.7 plants/100m². After two seasons without livestock grazing, mean crown volumes of willows (Salix spp.) increased 550% inside of wild ungulate exclosures and 195% outside, black cottonwood (Populus trichocarpa) 773% inside and 808% outside, and thin-leaf alder (Almis incana) 1046% inside and 198% outside, respectively. Willows were significantly impeded (p<0.Ol) mule deer and Rocky Mountain elk, alder samples were too small to statistically test, and cottonwood was not significantly impeded. However, impacts by deer and elk may be exaggerated due to high densities and the ungulate density-dynamics unique within the 77 km² Starkey Experimental Forest big-game enclosure surrounding the study site. Establishment rates are low at this time, i.e., only 10% of previously suppressed willows produced catkins. Although in transects densities increased by 5 new woody plants/lOOm² (50m of streambank). Other non-anthropogenic factors influencing the recovery of shrubs, included beaver which removed mainstems from 20% of willows, 11% of thin-leaf alder, and 4% of black cottonwood, and active insect defoliation which was noted on 16% of willows, 7% of thin-leaf alder, and 0% of black cottonwood. Crude protein levels measured in willow and alder leaves was relatively high (16.1 to 16.3%) helping to explain their palatability and use by wild and domestic herbivores. Few studies have quantified biomass, structure and composition of headwater riparian ecosystems. Data such as this are important given their dominant roles in ecosystem biodiversity, and aquatic function. To document relatively intact forested headwater ripanan conditions in the Upper Grande Ronde Basin, the biomass, structure and composition along six headwater reaches was quantified. Sampling was done using a nested belt transect/plot arrangement along 500 meter reaches. Total aboveground biomass (TAGB) ranged from 203 to 261 Mg/ha, with overstory conifers contributing 101 to 177 Mg/ha. Living understory components (saplings, seedlings, shrubs, and herbs) comprised 5 to 18 Mg/ha (2 to 9% of TAGB), while forest floor detrital accumulations comprised 65 to 101 Mg/ha (29 to 42% of TAGB). Average shade per day for July, 1993 ranged between 53% and 75%, reducing the unshaded solar energy potential of 2390 Mj/day to between 680 and 1280 Mj/day striking each m² of stream surface. This baseline reference information can serve in multi-disciplined research, as well as, be a basis for long term studies of natural systems responding to changing climate and different resource management scenarios. Title: The ecology of riparian ecosystems of Northeast Oregon : shrub recovery at Meadow Creek and the structure and biomass of headwater Upper Grande Ronde ecosystems Author: Case, Richard L. Riparian ecosystems play numerous and essential roles related to the quality and flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, these zones influence the integrity of the terrestrial as well as the entire aquatic-riverine ecosystem. Since Euro-American settlement in the West, the structure and condition of many riparian ecosystems has been significantly altered. To provide tools and an ecological perspective related to riparian restoration and management, and to document late 20th century headwater riparian structure and biomass in the Upper Grande Ronde Basin, this research project was undertaken. At Meadow Creek, the response of riparian hardwood species to the termination of livestock grazing was quantified. Regression equations were developed to predict shrub biomass. Permanently marked hardwood plants were measured annually to quantify parameters of growth (height, crown area, mainstem diameter, number of stems, biomass). Permanent belt transects on gravel bars were utilized to quantify rates of shrub establishment. Elk/deer-proof exclosures allowed the quantification of the browsing influence of wild ungulates. In 1991, initial shrub heights and densities reflected decades of grazing pressure. Mean heights of515 woody plants (14 species) was 47 cm and densities on gravel bars averaged 10.7 plants/100m². After two seasons without livestock grazing, mean crown volumes of willows (Salix spp.) increased 550% inside of wild ungulate exclosures and 195% outside, black cottonwood (Populus trichocarpa) 773% inside and 808% outside, and thin-leaf alder (Almis incana) 1046% inside and 198% outside, respectively. Willows were significantly impeded (p<0.Ol) mule deer and Rocky Mountain elk, alder samples were too small to statistically test, and cottonwood was not significantly impeded. However, impacts by deer and elk may be exaggerated due to high densities and the ungulate density-dynamics unique within the 77 km² Starkey Experimental Forest big-game enclosure surrounding the study site. Establishment rates are low at this time, i.e., only 10% of previously suppressed willows produced catkins. Although in transects densities increased by 5 new woody plants/lOOm² (50m of streambank). Other non-anthropogenic factors influencing the recovery of shrubs, included beaver which removed mainstems from 20% of willows, 11% of thin-leaf alder, and 4% of black cottonwood, and active insect defoliation which was noted on 16% of willows, 7% of thin-leaf alder, and 0% of black cottonwood. Crude protein levels measured in willow and alder leaves was relatively high (16.1 to 16.3%) helping to explain their palatability and use by wild and domestic herbivores. Few studies have quantified biomass, structure and composition of headwater riparian ecosystems. Data such as this are important given their dominant roles in ecosystem biodiversity, and aquatic function. To document relatively intact forested headwater ripanan conditions in the Upper Grande Ronde Basin, the biomass, structure and composition along six headwater reaches was quantified. Sampling was done using a nested belt transect/plot arrangement along 500 meter reaches. Total aboveground biomass (TAGB) ranged from 203 to 261 Mg/ha, with overstory conifers contributing 101 to 177 Mg/ha. Living understory components (saplings, seedlings, shrubs, and herbs) comprised 5 to 18 Mg/ha (2 to 9% of TAGB), while forest floor detrital accumulations comprised 65 to 101 Mg/ha (29 to 42% of TAGB). Average shade per day for July, 1993 ranged between 53% and 75%, reducing the unshaded solar energy potential of 2390 Mj/day to between 680 and 1280 Mj/day striking each m² of stream surface. This baseline reference information can serve in multi-disciplined research, as well as, be a basis for long term studies of natural systems responding to changing climate and different resource management scenarios. Close

• 5670. [Article] Water and Soil Management Practices to Enhance Plant Growth, Berry Development, and Fruit Quality of Northern Highbush Blueberry (Vaccinium corymbosum L.)

  Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions and new strategies are needed to maintain yield and fruit quality ...

  Citation × Citation Citation Abstract Copy Title: Water and Soil Management Practices to Enhance Plant Growth, Berry Development, and Fruit Quality of Northern Highbush Blueberry (Vaccinium corymbosum L.) Author: Almutairi, Khalid F. Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions and new strategies are needed to maintain yield and fruit quality with less water. Three potential options for reducing water use, including deficit irrigation, irrigation cut-offs, and crop thinning, were evaluated for 2 years in a mature planting of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’). Treatments consisted of no thinning and 50% crop removal in combination with either full irrigation at 100% of estimated crop evapotranspiration (ETsubscript c]), deficit irrigation at 50% ET[subscript c] (applied for the entire growing season), or full irrigation with irrigation cut-off for 4–6 weeks during early or late stages of fruit development. Stem water potential was similar with full and deficit irrigation but, regardless of crop thinning, declined by 0.5–0.6 MPa when irrigation was cut-off early and by > 2.0 MPa when irrigation was cut-off late. In one or both years, the fruiting season was advanced with either deficit irrigation or late cut-off, whereas cutting off irrigation early delayed the season. Yield was not affected by deficit irrigation in plants with a full crop load but was reduced by an average of 35% when irrigation was cut-off late each year. Cutting off irrigation early likewise reduced yield, but only in the second year when the plants were not thinned; however, early cut-off also reduced fruit soluble solids and berry weight by 7% to 24%compared to full irrigation. Cutting off irrigation late produced the smallest and firmest fruit with the highest soluble solids and total acidity among the treatments, as well as the slowest rate of fruit loss in cold storage. Deficit irrigation had the least effect on fruit quality and, based on these results, appears to be the most viable option for maintaining yield with less water (2.5 ML·ha⁻¹ less water per season). A second study was conducted in a 7-year-old field of certified organic highbush blueberry. Two cultivars (‘Duke’ and ‘Liberty’) mulched with either porous polyethylene ground cover (“weed mat”) or yard debris compost topped with sawdust (sawdust+compost) and each fertilized with either feather meal or fish emulsion were evaluated. One-year-old fruiting laterals were randomly-selected at three heights (top, middle, and bottom) on the east and west side of the plants. Bud, flower, and fruit development were monitored through fruit harvest. There was relatively little effect of mulch type or fertilizer source on the measured variables. Fruit harvest occurred ≈8 d after the fruit were fully blue and ranged from 2-25 July 2012 and 26 June-3 July 2013 in ‘Duke’ and from 1-20 Aug. 2012 and 17 July-7 Aug. 2013 in ‘Liberty’. Proportionally more fruit buds occurred on middle laterals than upper and lower laterals. The dates of bud swell and bud break were not affected by cultivar or lateral position. ‘Duke’ and ‘Liberty’ produced 6-8 and 7-9 flowers/bud, respectively. Fruit set was high in both cultivars, averaging ≈95%. However, 13-18% and 29-38 % of the initial set fruit dropped in ’Duke’ and ‘Liberty’ in late May to early June. Fruit ripening was more uniform within clusters in ‘Duke’ than in ‘Liberty’, and average fruit size was similar among harvests in ‘Duke’ but decreased by 25-40% between the first and last harvest in ‘Liberty’. Fruit matured 3−5 d earlier on the east side of the canopy than on the west side. The results suggest that pruning proportionally more on the lower part of the canopy than on the upper part will result in larger fruit at harvest than uniform pruning throughout the bush. The final study was conducted to determine the potential of applying micronized elemental sulfur (S°) by chemigation through the drip system to reduce high soil pH in a new planting of ‘Duke’ blueberry. The S° was mixed with water and injected weekly for 2 months prior to planting, as well as 2 years after planting, atrates of 0, 50, 100 and 150 kg·ha⁻¹ per year, and was compared to the conventional practice of incorporating prilled S° into the soil prior to planting (two applications of 750 kg·ha⁻¹ each). Chemigation quickly reduced soil pH (0-10 cm) within a month from 6.6 with no S° to 6.1 with 50 kg·ha-1 S° and 5.8 with 100 or 150 kg·ha⁻¹ S°. The change was short-term, however, and by May of the following year, soil pH averaged 6.7, 6.5, 6.2, and 6.1 with each increasing rate of S° chemigation, respectively. The conventional treatment, in comparison, averaged 6.6 on the first date and 6.3 on the second date. In July of the following year, soil pH ranged from an average of 6.4 with no S° to 6.2 with 150 kg·ha⁻¹ S° and 5.5 with prilled S°. Soil pH declined thereafter to as low as 5.9 with additional S° chemigation and at lower depths (10-30 cm) was similar to the conventional treatment. None of the treatments had any effect on winter pruning weight in year 1 or on yield, berry weight, and plant dry weight in year 2. Chemigation with S° can be used to quickly reduce soil pH following planting and, therefore, may be a useful practice to correct high pH problems in established blueberry fields. However, it was less effective and more time consuming than applying prilled S° prior to planting. Title: Water and Soil Management Practices to Enhance Plant Growth, Berry Development, and Fruit Quality of Northern Highbush Blueberry (Vaccinium corymbosum L.) Author: Almutairi, Khalid F. Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions and new strategies are needed to maintain yield and fruit quality with less water. Three potential options for reducing water use, including deficit irrigation, irrigation cut-offs, and crop thinning, were evaluated for 2 years in a mature planting of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’). Treatments consisted of no thinning and 50% crop removal in combination with either full irrigation at 100% of estimated crop evapotranspiration (ETsubscript c]), deficit irrigation at 50% ET[subscript c] (applied for the entire growing season), or full irrigation with irrigation cut-off for 4–6 weeks during early or late stages of fruit development. Stem water potential was similar with full and deficit irrigation but, regardless of crop thinning, declined by 0.5–0.6 MPa when irrigation was cut-off early and by > 2.0 MPa when irrigation was cut-off late. In one or both years, the fruiting season was advanced with either deficit irrigation or late cut-off, whereas cutting off irrigation early delayed the season. Yield was not affected by deficit irrigation in plants with a full crop load but was reduced by an average of 35% when irrigation was cut-off late each year. Cutting off irrigation early likewise reduced yield, but only in the second year when the plants were not thinned; however, early cut-off also reduced fruit soluble solids and berry weight by 7% to 24%compared to full irrigation. Cutting off irrigation late produced the smallest and firmest fruit with the highest soluble solids and total acidity among the treatments, as well as the slowest rate of fruit loss in cold storage. Deficit irrigation had the least effect on fruit quality and, based on these results, appears to be the most viable option for maintaining yield with less water (2.5 ML·ha⁻¹ less water per season). A second study was conducted in a 7-year-old field of certified organic highbush blueberry. Two cultivars (‘Duke’ and ‘Liberty’) mulched with either porous polyethylene ground cover (“weed mat”) or yard debris compost topped with sawdust (sawdust+compost) and each fertilized with either feather meal or fish emulsion were evaluated. One-year-old fruiting laterals were randomly-selected at three heights (top, middle, and bottom) on the east and west side of the plants. Bud, flower, and fruit development were monitored through fruit harvest. There was relatively little effect of mulch type or fertilizer source on the measured variables. Fruit harvest occurred ≈8 d after the fruit were fully blue and ranged from 2-25 July 2012 and 26 June-3 July 2013 in ‘Duke’ and from 1-20 Aug. 2012 and 17 July-7 Aug. 2013 in ‘Liberty’. Proportionally more fruit buds occurred on middle laterals than upper and lower laterals. The dates of bud swell and bud break were not affected by cultivar or lateral position. ‘Duke’ and ‘Liberty’ produced 6-8 and 7-9 flowers/bud, respectively. Fruit set was high in both cultivars, averaging ≈95%. However, 13-18% and 29-38 % of the initial set fruit dropped in ’Duke’ and ‘Liberty’ in late May to early June. Fruit ripening was more uniform within clusters in ‘Duke’ than in ‘Liberty’, and average fruit size was similar among harvests in ‘Duke’ but decreased by 25-40% between the first and last harvest in ‘Liberty’. Fruit matured 3−5 d earlier on the east side of the canopy than on the west side. The results suggest that pruning proportionally more on the lower part of the canopy than on the upper part will result in larger fruit at harvest than uniform pruning throughout the bush. The final study was conducted to determine the potential of applying micronized elemental sulfur (S°) by chemigation through the drip system to reduce high soil pH in a new planting of ‘Duke’ blueberry. The S° was mixed with water and injected weekly for 2 months prior to planting, as well as 2 years after planting, atrates of 0, 50, 100 and 150 kg·ha⁻¹ per year, and was compared to the conventional practice of incorporating prilled S° into the soil prior to planting (two applications of 750 kg·ha⁻¹ each). Chemigation quickly reduced soil pH (0-10 cm) within a month from 6.6 with no S° to 6.1 with 50 kg·ha-1 S° and 5.8 with 100 or 150 kg·ha⁻¹ S°. The change was short-term, however, and by May of the following year, soil pH averaged 6.7, 6.5, 6.2, and 6.1 with each increasing rate of S° chemigation, respectively. The conventional treatment, in comparison, averaged 6.6 on the first date and 6.3 on the second date. In July of the following year, soil pH ranged from an average of 6.4 with no S° to 6.2 with 150 kg·ha⁻¹ S° and 5.5 with prilled S°. Soil pH declined thereafter to as low as 5.9 with additional S° chemigation and at lower depths (10-30 cm) was similar to the conventional treatment. None of the treatments had any effect on winter pruning weight in year 1 or on yield, berry weight, and plant dry weight in year 2. Chemigation with S° can be used to quickly reduce soil pH following planting and, therefore, may be a useful practice to correct high pH problems in established blueberry fields. However, it was less effective and more time consuming than applying prilled S° prior to planting. Close