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• 381. [Article] Investigating Vibrio parahaemolyticus interactions with the Pacific oyster, Crassostrea gigas

  Vibrio parahaemolyticus is a Gram-negative, halophilic, human pathogenic bacterium ubiquitous in the marine environment. Like many Vibrio species, V. parahaemolyticus commonly associates with shellfish, ...

  Citation × Citation Citation Abstract Copy Title: Investigating Vibrio parahaemolyticus interactions with the Pacific oyster, Crassostrea gigas Author: Aagesen, Alisha M. Vibrio parahaemolyticus is a Gram-negative, halophilic, human pathogenic bacterium ubiquitous in the marine environment. Like many Vibrio species, V. parahaemolyticus commonly associates with shellfish, particularly oysters. Ingestion of a raw or under cooked oysters contaminated with V. parahaemolyticus can cause gastroenteritis, which is typically self-limiting and rarely causes death. Globally, oyster production is highly lucrative, especially on the West Coast of the United States where approximately 60% of oyster production occurs each year. Outbreaks of V. parahaemolyticus can result in a significant public health problem as well as an economic burden for the oyster farms implicated in the outbreak. With the increase in overall V. parahaemolyticus outbreaks, improved post-harvest processing strategies have been developed to reduce this natural contaminant. Depuration was developed to allow shellfish to purge contaminants from their tissues into the clean, flowing seawater where they are held. This post-harvest processing technique can typically reduce fecal contaminants from the oyster tissues but is relatively ineffective at eliminating V. parahaemolyticus and other Vibrio species.. Thus, improved methods for reducing this and other human pathogenic Vibrio are needed to effectively produce safer oysters for the consumer. To develop more effective and novel V. parahaemolyticus intervention strategies, first we must identify the factors that are involved in V. parahaemolyticus colonization of the oyster, allowing them toresist depuration. This study sought to investigate specific factors utilized by V. parahaemolyticus and, in the process, determined that various strains of V. parahaemolyticus have different alleles of the Type IV pili, mannose-sensitive hemagglutinin (MSHA)and chitin-regulated pilus (PilA). In addition, we expanded our investigations into the allelic diversity of MSHA and PilA from Vibrio cholerae and Vibrio vulnificus and found that V. cholerae strains that possess the Type IV toxin co-regulated pilus (TCP) maintained highly conserved MSHA and PilA sequences while strains of V. cholerae without TCP, and all of the V. vulnificus and V. parahaemolyticus strains examined, had highly divergent sequences with no discernable connection to isolation source or observed phenotype. Following that discovery, we determined that Type I, and Type IV pili, as well as polar and lateral flagellar systems contribute to V. parahaemolyticus persistence in the Pacific oyster during depuration, while Type III secretion systems and phase variation do not. Overall, we have identified factors involved in colonization of the Pacific oyster by V. parahaemolyticus. Future studies investigating conditions that affect pili and flagella production in V. parahaemolyticus may provide novel depuration conditions that could easily and effectively increase the efficiency of oyster depuration, ultimately reducing the risk of seafood-borne illness by V. parahaemolyticus associated with oysters. Title: Investigating Vibrio parahaemolyticus interactions with the Pacific oyster, Crassostrea gigas Author: Aagesen, Alisha M. Vibrio parahaemolyticus is a Gram-negative, halophilic, human pathogenic bacterium ubiquitous in the marine environment. Like many Vibrio species, V. parahaemolyticus commonly associates with shellfish, particularly oysters. Ingestion of a raw or under cooked oysters contaminated with V. parahaemolyticus can cause gastroenteritis, which is typically self-limiting and rarely causes death. Globally, oyster production is highly lucrative, especially on the West Coast of the United States where approximately 60% of oyster production occurs each year. Outbreaks of V. parahaemolyticus can result in a significant public health problem as well as an economic burden for the oyster farms implicated in the outbreak. With the increase in overall V. parahaemolyticus outbreaks, improved post-harvest processing strategies have been developed to reduce this natural contaminant. Depuration was developed to allow shellfish to purge contaminants from their tissues into the clean, flowing seawater where they are held. This post-harvest processing technique can typically reduce fecal contaminants from the oyster tissues but is relatively ineffective at eliminating V. parahaemolyticus and other Vibrio species.. Thus, improved methods for reducing this and other human pathogenic Vibrio are needed to effectively produce safer oysters for the consumer. To develop more effective and novel V. parahaemolyticus intervention strategies, first we must identify the factors that are involved in V. parahaemolyticus colonization of the oyster, allowing them toresist depuration. This study sought to investigate specific factors utilized by V. parahaemolyticus and, in the process, determined that various strains of V. parahaemolyticus have different alleles of the Type IV pili, mannose-sensitive hemagglutinin (MSHA)and chitin-regulated pilus (PilA). In addition, we expanded our investigations into the allelic diversity of MSHA and PilA from Vibrio cholerae and Vibrio vulnificus and found that V. cholerae strains that possess the Type IV toxin co-regulated pilus (TCP) maintained highly conserved MSHA and PilA sequences while strains of V. cholerae without TCP, and all of the V. vulnificus and V. parahaemolyticus strains examined, had highly divergent sequences with no discernable connection to isolation source or observed phenotype. Following that discovery, we determined that Type I, and Type IV pili, as well as polar and lateral flagellar systems contribute to V. parahaemolyticus persistence in the Pacific oyster during depuration, while Type III secretion systems and phase variation do not. Overall, we have identified factors involved in colonization of the Pacific oyster by V. parahaemolyticus. Future studies investigating conditions that affect pili and flagella production in V. parahaemolyticus may provide novel depuration conditions that could easily and effectively increase the efficiency of oyster depuration, ultimately reducing the risk of seafood-borne illness by V. parahaemolyticus associated with oysters. Close

• 382. [Article] Willamette Biological Opinion Hatchery Research 2012 Annual Report

  Abstract -- In the Willamette Basin upstream of Willamette Falls (Figure 1), there are four distinct spring Chinook salmon hatchery programs (North Santiam [Stock 21], South Santiam [Stock 24], McKenzie ...

  Citation × Citation Citation Abstract Copy Title: Willamette Biological Opinion Hatchery Research 2012 Annual Report Abstract -- In the Willamette Basin upstream of Willamette Falls (Figure 1), there are four distinct spring Chinook salmon hatchery programs (North Santiam [Stock 21], South Santiam [Stock 24], McKenzie [Stock 23], and Middle Fork Willamette [Stock 22]) that are managed for integrated harvest augmentation as part of the Willamette Valley Hatchery Mitigation Program. These hatchery stocks, as well as all naturally spawned spring Chinook salmon in the Upper Willamette Basin, are included in the Upper Willamette River Evolutionary Significant Unit (ESU). The Upper Willamette Summer Steelhead Hatchery Program is managed to provide fish for sport fisheries and to replace loss of fisheries caused by habitat and passage loss/degradation in the Willamette Basin and other lower Columbia basins. The hatchery program currently includes annual smolt releases into the North Santiam, South Santiam, McKenzie, and Middle Fork Willamette rivers. Lack of access to historical habitat and degradation of remaining habitat below the dams, especially in the North and South Santiam (the “core” populations) are the key limiting factors shared between winter steelhead and spring Chinook salmon. In addition, summer steelhead are not native to the Willamette Basin upstream of Willamette Falls and a third, unique, limiting factor is the potential for competition, predation and genetic introgression from out-of-ESU hatchery fish interacting with and spawning in the wild with the native winter-run. Summer steelhead were first introduced to the South Santiam River as mitigation for lost winter steelhead production in areas inundated by Foster and Green Peter reservoirs. The scope of work actually directed towards risks posed by summer steelhead is much smaller than that directed towards issues faced by spring Chinook. The Willamette Project Biological Opinion (BiOP; NMFS 2008) required the USACE to collect information to describe the nature and extent of these potential effects but beyond relatively small-scale studies often integrated into much larger studies involving spring Chinook, more focused work will only follow commitment of significantly more effort and funds. 11 This report fulfills a requirement under Task Order NWPPM-10-FH-06, covering activities of May 2012–June 2012, that were implemented by ODFW on behalf of the Corps to assist with meeting requirements of the reasonable and prudent alternatives (RPAs) and measures prescribed in the Willamette Project Biological Opinion (BiOp) of July 2008 (NOAA 2008). The Corps provided funding to continue ongoing monitoring activities and initiate long-term planning. Title: Willamette Biological Opinion Hatchery Research 2012 Annual Report Abstract -- In the Willamette Basin upstream of Willamette Falls (Figure 1), there are four distinct spring Chinook salmon hatchery programs (North Santiam [Stock 21], South Santiam [Stock 24], McKenzie [Stock 23], and Middle Fork Willamette [Stock 22]) that are managed for integrated harvest augmentation as part of the Willamette Valley Hatchery Mitigation Program. These hatchery stocks, as well as all naturally spawned spring Chinook salmon in the Upper Willamette Basin, are included in the Upper Willamette River Evolutionary Significant Unit (ESU). The Upper Willamette Summer Steelhead Hatchery Program is managed to provide fish for sport fisheries and to replace loss of fisheries caused by habitat and passage loss/degradation in the Willamette Basin and other lower Columbia basins. The hatchery program currently includes annual smolt releases into the North Santiam, South Santiam, McKenzie, and Middle Fork Willamette rivers. Lack of access to historical habitat and degradation of remaining habitat below the dams, especially in the North and South Santiam (the “core” populations) are the key limiting factors shared between winter steelhead and spring Chinook salmon. In addition, summer steelhead are not native to the Willamette Basin upstream of Willamette Falls and a third, unique, limiting factor is the potential for competition, predation and genetic introgression from out-of-ESU hatchery fish interacting with and spawning in the wild with the native winter-run. Summer steelhead were first introduced to the South Santiam River as mitigation for lost winter steelhead production in areas inundated by Foster and Green Peter reservoirs. The scope of work actually directed towards risks posed by summer steelhead is much smaller than that directed towards issues faced by spring Chinook. The Willamette Project Biological Opinion (BiOP; NMFS 2008) required the USACE to collect information to describe the nature and extent of these potential effects but beyond relatively small-scale studies often integrated into much larger studies involving spring Chinook, more focused work will only follow commitment of significantly more effort and funds. 11 This report fulfills a requirement under Task Order NWPPM-10-FH-06, covering activities of May 2012–June 2012, that were implemented by ODFW on behalf of the Corps to assist with meeting requirements of the reasonable and prudent alternatives (RPAs) and measures prescribed in the Willamette Project Biological Opinion (BiOp) of July 2008 (NOAA 2008). The Corps provided funding to continue ongoing monitoring activities and initiate long-term planning. Close

• 383. [Article] Willamette Biological Opinion Hatchery Research 2013 Annual Report

  Abstract -- In the Willamette Basin upstream of Willamette Falls (Figure 1), there are four distinct spring Chinook salmon hatchery programs (North Santiam [Stock 21], South Santiam [Stock 24], McKenzie ...

  Citation × Citation Citation Abstract Copy Title: Willamette Biological Opinion Hatchery Research 2013 Annual Report Abstract -- In the Willamette Basin upstream of Willamette Falls (Figure 1), there are four distinct spring Chinook salmon hatchery programs (North Santiam [Stock 21], South Santiam [Stock 24], McKenzie [Stock 23], and Middle Fork Willamette [Stock 22]) that are managed for integrated harvest augmentation as part of the Willamette Valley Hatchery Mitigation Program. These hatchery stocks, as well as all naturally spawned spring Chinook salmon in the Upper Willamette Basin, are included in the Upper Willamette River Evolutionary Significant Unit (ESU). The Upper Willamette Summer Steelhead Hatchery Program is managed to provide fish for sport fisheries and to replace loss of fisheries caused by habitat and passage loss/degradation in the Willamette and other lower Columbia basins. The hatchery program currently includes annual smolt releases into the North Santiam, South Santiam, McKenzie, and Middle Fork Willamette rivers. Lack of access to historical habitat and degradation of remaining habitat below the dams, especially in the North and South Santiam (the “core” populations) are the key limiting factors shared between winter steelhead and spring Chinook salmon. In addition, summer steelhead are not native to the Willamette Basin upstream of Willamette Falls and a third, unique, limiting factor is the potential for competition, predation and genetic introgression from out-of-ESU hatchery fish interacting with and spawning in the wild with the native winter-run(Johnson et al. 2013). Summer steelhead were first introduced to the South Santiam River as mitigation for lost winter steelhead production in areas inundated by Foster and Green Peter reservoirs. The scope of work actually directed towards risks posed by summer steelhead is much smaller than that directed towards issues faced by spring Chinook salmon. The Willamette Project Biological Opinion (BiOP; NMFS 2008) required the USACE to collect information to describe the nature and extent of these potential effects but beyond relatively small-scale studies often integrated into much larger studies involving spring Chinook salmon, more focused work on steelhead will only follow commitment of significantly more effort and funds. This report fulfills a requirement under Task Order W9127N-12-2-0004-1009 covering activities of May 2013–June 2014, that were implemented by ODFW on behalf of the Corps to assist with meeting requirements of the reasonable and prudent alternatives (RPAs) and measures prescribed in the Willamette Project Biological Opinion (BiOp) of July 2008 (NOAA 2008). The Corps provided funding to continue ongoing monitoring activities and initiate long-term planning. The conceptual relationship between spring Chinook salmon prioritized objectives, RPAs, and 2013 work tasks is depicted in Figure 2. In future work, the intent is to expand the conceptual framework provided in Figure 2 and develop specific numerical goals in terms of, for example, adult returns desired per subbasin. A detailed list of tasks associated with the work is provided in Appendix 1. Title: Willamette Biological Opinion Hatchery Research 2013 Annual Report Abstract -- In the Willamette Basin upstream of Willamette Falls (Figure 1), there are four distinct spring Chinook salmon hatchery programs (North Santiam [Stock 21], South Santiam [Stock 24], McKenzie [Stock 23], and Middle Fork Willamette [Stock 22]) that are managed for integrated harvest augmentation as part of the Willamette Valley Hatchery Mitigation Program. These hatchery stocks, as well as all naturally spawned spring Chinook salmon in the Upper Willamette Basin, are included in the Upper Willamette River Evolutionary Significant Unit (ESU). The Upper Willamette Summer Steelhead Hatchery Program is managed to provide fish for sport fisheries and to replace loss of fisheries caused by habitat and passage loss/degradation in the Willamette and other lower Columbia basins. The hatchery program currently includes annual smolt releases into the North Santiam, South Santiam, McKenzie, and Middle Fork Willamette rivers. Lack of access to historical habitat and degradation of remaining habitat below the dams, especially in the North and South Santiam (the “core” populations) are the key limiting factors shared between winter steelhead and spring Chinook salmon. In addition, summer steelhead are not native to the Willamette Basin upstream of Willamette Falls and a third, unique, limiting factor is the potential for competition, predation and genetic introgression from out-of-ESU hatchery fish interacting with and spawning in the wild with the native winter-run(Johnson et al. 2013). Summer steelhead were first introduced to the South Santiam River as mitigation for lost winter steelhead production in areas inundated by Foster and Green Peter reservoirs. The scope of work actually directed towards risks posed by summer steelhead is much smaller than that directed towards issues faced by spring Chinook salmon. The Willamette Project Biological Opinion (BiOP; NMFS 2008) required the USACE to collect information to describe the nature and extent of these potential effects but beyond relatively small-scale studies often integrated into much larger studies involving spring Chinook salmon, more focused work on steelhead will only follow commitment of significantly more effort and funds. This report fulfills a requirement under Task Order W9127N-12-2-0004-1009 covering activities of May 2013–June 2014, that were implemented by ODFW on behalf of the Corps to assist with meeting requirements of the reasonable and prudent alternatives (RPAs) and measures prescribed in the Willamette Project Biological Opinion (BiOp) of July 2008 (NOAA 2008). The Corps provided funding to continue ongoing monitoring activities and initiate long-term planning. The conceptual relationship between spring Chinook salmon prioritized objectives, RPAs, and 2013 work tasks is depicted in Figure 2. In future work, the intent is to expand the conceptual framework provided in Figure 2 and develop specific numerical goals in terms of, for example, adult returns desired per subbasin. A detailed list of tasks associated with the work is provided in Appendix 1. Close

• 384. [Article] Klamath Mountains Province Steelhead Project, 1999 Annual Report Report Number: OPSW-ODFW-2002-09

  Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial ...

  Citation × Citation Citation Abstract Copy Title: Klamath Mountains Province Steelhead Project, 1999 Annual Report Report Number: OPSW-ODFW-2002-09 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define “sustainable and productive” by committing the Oregon Department of Fish and Wildlife (ODFW) to establish “Population Health Goals” for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the “half-pounder” run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990a; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU “are relatively healthy and certainly do not warrant listing as threatened under the ESA”. Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 1999. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Attainment of all of the population health goals will likely indicate that the populations of wild steelhead in the KMP are healthy and may allow managers to restore harvest opportunities for wild fish. Conversely, failure to attain any of the population health goals will likely indicate that the populations are depressed and would likely lead to actions designed to minimize fishing mortality. However, in most years it is likely that some goals will be attained while some will not be attained. Under that scenario, and depending on which goals are attained, selective fisheries, like the current one for wild winter steelhead in the Rogue River, remain as viable options for fishery managers. Title: Klamath Mountains Province Steelhead Project, 1999 Annual Report Report Number: OPSW-ODFW-2002-09 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define “sustainable and productive” by committing the Oregon Department of Fish and Wildlife (ODFW) to establish “Population Health Goals” for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the “half-pounder” run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990a; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU “are relatively healthy and certainly do not warrant listing as threatened under the ESA”. Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 1999. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Attainment of all of the population health goals will likely indicate that the populations of wild steelhead in the KMP are healthy and may allow managers to restore harvest opportunities for wild fish. Conversely, failure to attain any of the population health goals will likely indicate that the populations are depressed and would likely lead to actions designed to minimize fishing mortality. However, in most years it is likely that some goals will be attained while some will not be attained. Under that scenario, and depending on which goals are attained, selective fisheries, like the current one for wild winter steelhead in the Rogue River, remain as viable options for fishery managers. Close

• 385. [Article] Klamath Mountains Province Steelhead Project, 2000-01 Annual Report Report Number: OPSW-ODFW-2003-08

  Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial ...

  Citation × Citation Citation Abstract Copy Title: Klamath Mountains Province Steelhead Project, 2000-01 Annual Report Report Number: OPSW-ODFW-2003-08 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define "sustainable and productive" by committing the Oregon Department of Fish and Wildlife (ODFW) to establish "Population Health Goals" for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the "half-pounder" run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU "are relatively healthy and certainly do not warrant listing as threatened under the ESA". Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 2000. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Directed sampling began in 1999 and the findings from 1999 were reported by Satterthwaite (2002a). Title: Klamath Mountains Province Steelhead Project, 2000-01 Annual Report Report Number: OPSW-ODFW-2003-08 Abstract -- The steelhead supplement to the Oregon Plan for Salmon and Watersheds (OSPW) is intended to maintain wild steelhead populations in Oregon at sustainable and productive levels that provide substantial environmental, cultural, and economic benefits. The OSPW attempts to better define "sustainable and productive" by committing the Oregon Department of Fish and Wildlife (ODFW) to establish "Population Health Goals" for each Evolutionary Significant Unit (ESU) of wild steelhead within the state. In addition, section ODFW IB1S of the plan calls for ODFW to assess adult escapement and juvenile production of wild steelhead in each ESU. The National Marine Fisheries Service identified seven ESUs for steelhead in Oregon and concluded that steelhead produced in coastal basins between Cape Blanco in southern Oregon and the Klamath River Basin in northern California constitutes one ESU. This area closely corresponds to the geologic boundaries of the Klamath Mountains Province (KMP). Steelhead in the KMP differ from those in adjoining areas because of distinctive life history and genetic characteristics (Busby et al. 1994). Primary differences in life history parameters have been identified for wild KMP steelhead. Summer steelhead and winter steelhead differ in time of return as adults, tendency to return to fresh water on a false spawning migration (the "half-pounder" run), age at ocean entry, growth rate and migration patterns of juveniles in fresh water (ODFW 1990; ODFW 1994). As a result of these differences, separate health goals seem warranted for summer and winter steelhead populations. Winter steelhead inhabit streams throughout the KMP, while summer steelhead are found only in a portion of the Rogue River Basin. However, the distribution of summer and winter steelhead overlap in major areas of the Rogue River Basin (Everest 1973) and as juveniles of the respective races cannot be differentiated, some population health goals will have to apply to both races. The status of wild steelhead in the Klamath Mountains Province ESU is not readily apparent. Busby et al. (1994) concluded that the steelhead in this ESU “is not now at risk of extinction, but if present trends continue, it is likely to become so in the foreseeable future”. In contrast, Chilcote (1998) concluded that almost all steelhead populations in the Oregon portion of the ESU "are relatively healthy and certainly do not warrant listing as threatened under the ESA". Uncertainty as to the status of the resource, coupled with the comprehensive conservation plan developed by Oregon and the termination of wild fish harvest in all streams except the Rogue River, lead the National Marine Fisheries Service to defer a listing of KMP steelhead under the Endangered Species Act. However, KMP steelhead remained a candidate species during 2000. The goal of this project is to develop and implement assessment methods to determine the status of wild steelhead in the Oregon portion of the KMP. Project objectives include (1) develop population health goals and allied monitoring methods and (2) determine resource status in relation to health goals. Directed sampling began in 1999 and the findings from 1999 were reported by Satterthwaite (2002a). Close

• 386. [Article] First Report of Phytophthora occultans Causing Root and Collar Rot on Ceanothus, Boxwood, Rhododendron, and Other Hosts in Horticultural Nurseries in Oregon, USA

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

  Citation × Citation Citation Abstract Copy Title: First Report of Phytophthora occultans Causing Root and Collar Rot on Ceanothus, Boxwood, Rhododendron, and Other Hosts in Horticultural Nurseries in Oregon, USA Author: Goheen, E. M., Grünwald, N. J., Fieland, V. J., Sutton, W., Reeser, P. W., Hansen, E. M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published news item is copyrighted by American Phytopathological Society and can be found at: http://apsjournals.apsnet.org/loi/pdis Title: First Report of Phytophthora occultans Causing Root and Collar Rot on Ceanothus, Boxwood, Rhododendron, and Other Hosts in Horticultural Nurseries in Oregon, USA Author: Goheen, E. M., Grünwald, N. J., Fieland, V. J., Sutton, W., Reeser, P. W., Hansen, E. M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published news item is copyrighted by American Phytopathological Society and can be found at: http://apsjournals.apsnet.org/loi/pdis Close

• 387. [Article] Grass seed quality in relation to time of windrowing

  This study was undertaken to obtain information on the quality of grass seed when windrowed at the high moisture levels necessary for obtaining maximum yields. A secondary goal was to monitor moisture ...

  Citation × Citation Citation Abstract Copy Title: Grass seed quality in relation to time of windrowing Author: Dübbern de Souza, Francisco Humberto This study was undertaken to obtain information on the quality of grass seed when windrowed at the high moisture levels necessary for obtaining maximum yields. A secondary goal was to monitor moisture and temperature fluctuations in the windrow and to relate their effects to development and deterioration of the seed. Three species of perennial grasses were included in the study: tall fescue (Festuca arundinacea Schreb.) variety "Fawn", orchardgrass (Dactylis glomerata L.) variety "Potomac", and perennial ryegrass (Lolium perenne L.) variety "Linn". The effect of heading date on seed development at the recommended windrowing time was evaluated with individually tagged panicles. Tall fescue was windrowed on 28 June, 01 July and 06 July; orchardgrass on 28 June, 01 July and 06 July; and perennial ryegrass on 01 July, 06 July and 16 July. These dates were chosen to provide windrows mowed at moisture levels higher than, equal to, and lower than the optimum for maximum yields of pure live seed. Moisture and temperature fluctuations in the windrow were monitored and changes in seed development and deterioration were evaluated. Heading date influenced several seed quality characteristics at the recommended time for windrowing. Early inflorescences were lowest in seed moisture content. Tall fescue and perennial ryegrass seeds from the Late group, and orchardgrass seeds from the Intermediate and Late groups had not attained maximum seed weight. Seedlings of tall fescue and orchardgrass produced by seeds from the Late group had not attained maximum shoot weight. Seeds of all inflorescence age groups reached maximum viability several days before optimum windrowing date. Seed moisture contents when windrowed were 51.6, 41.5, and 15.9% in tall fescue, 44.8, 41.4 and 30.7% in orchardgrass, and 49.8, 28.5 and 19.1% in perennial ryegrass. During periods without rainfall, seed moisture decreased rapidly during the day, increased during the night, and decreased to a new low the following day. Several rains occurred during this period, raising seed moisture levels above 40%. During the drying period, seed moisture in the lower part of the perrenial ryegrass windrow was as much as 8% higher than seed in the upper part. The average maximum temperatures in the upper and lower portions of the perennial ryegrass windrow were 38.3 and 24. 3°C during July and 31.1 and 19. 2⁰C during August. The maximum temperature reached in the upper part was 47°C on 28 and 29 July. Each weeks' delay in windrowing resulted in improved seed quality, with the greatest improvement occurring between the first and second cutting, However, the data support Klein and Harmond's recommendations for windrowing tall fescue at 43% moisture, orchardgrass at 44% moisture, and perennial ryegrass at 35% moisture. Perennial ryegrass seed quality was not improved by delaying windrowing, while orchardgrass and tall fescue seeds increased somewhat in weight. Because of the risk of increased shattering losses, delaying windrowing to improve seed quality does not appear justified. A small amount of seed development took place while the seeds were in the windrow. Seed weight of tall fescue harvested at 51.6% moisture increased from 250.6 to 279.6 mg/ 100 seeds. No increase in seed weight occurred in the other species or windrowing dates. After several days in the windrow, speed of germination increased in all three species. Germination percentage, seedling emergence, and shoot weight did not improve after windrowing. Very little seed deterioration occurred during the first month in the windrow. A perceptible drop in germination of orchardgrass and perennial ryegrass occurred during the 2 weeks prior to the 19 August sampling date. Seed weight declined by the end of the experimental period in all three crops. Some germinated seeds were found in the perennial ryegras windrows by the end of August. No reduction in speed of germination or shoot weight occurred, while there was a trend toward reduced seedling emergence near the end of the experimental period. There were no indications that the stage of maturity when harvested influenced the rate of seed deterioration in the windrow. The probability of seed deterioration occurring at a faster rate than in 1976 is not great since a total of 75.69 mm (2.98 in) of rain fell during the experimental period, compared to a normal rainfall of 27.43 mm (1.08 in). Title: Grass seed quality in relation to time of windrowing Author: Dübbern de Souza, Francisco Humberto This study was undertaken to obtain information on the quality of grass seed when windrowed at the high moisture levels necessary for obtaining maximum yields. A secondary goal was to monitor moisture and temperature fluctuations in the windrow and to relate their effects to development and deterioration of the seed. Three species of perennial grasses were included in the study: tall fescue (Festuca arundinacea Schreb.) variety "Fawn", orchardgrass (Dactylis glomerata L.) variety "Potomac", and perennial ryegrass (Lolium perenne L.) variety "Linn". The effect of heading date on seed development at the recommended windrowing time was evaluated with individually tagged panicles. Tall fescue was windrowed on 28 June, 01 July and 06 July; orchardgrass on 28 June, 01 July and 06 July; and perennial ryegrass on 01 July, 06 July and 16 July. These dates were chosen to provide windrows mowed at moisture levels higher than, equal to, and lower than the optimum for maximum yields of pure live seed. Moisture and temperature fluctuations in the windrow were monitored and changes in seed development and deterioration were evaluated. Heading date influenced several seed quality characteristics at the recommended time for windrowing. Early inflorescences were lowest in seed moisture content. Tall fescue and perennial ryegrass seeds from the Late group, and orchardgrass seeds from the Intermediate and Late groups had not attained maximum seed weight. Seedlings of tall fescue and orchardgrass produced by seeds from the Late group had not attained maximum shoot weight. Seeds of all inflorescence age groups reached maximum viability several days before optimum windrowing date. Seed moisture contents when windrowed were 51.6, 41.5, and 15.9% in tall fescue, 44.8, 41.4 and 30.7% in orchardgrass, and 49.8, 28.5 and 19.1% in perennial ryegrass. During periods without rainfall, seed moisture decreased rapidly during the day, increased during the night, and decreased to a new low the following day. Several rains occurred during this period, raising seed moisture levels above 40%. During the drying period, seed moisture in the lower part of the perrenial ryegrass windrow was as much as 8% higher than seed in the upper part. The average maximum temperatures in the upper and lower portions of the perennial ryegrass windrow were 38.3 and 24. 3°C during July and 31.1 and 19. 2⁰C during August. The maximum temperature reached in the upper part was 47°C on 28 and 29 July. Each weeks' delay in windrowing resulted in improved seed quality, with the greatest improvement occurring between the first and second cutting, However, the data support Klein and Harmond's recommendations for windrowing tall fescue at 43% moisture, orchardgrass at 44% moisture, and perennial ryegrass at 35% moisture. Perennial ryegrass seed quality was not improved by delaying windrowing, while orchardgrass and tall fescue seeds increased somewhat in weight. Because of the risk of increased shattering losses, delaying windrowing to improve seed quality does not appear justified. A small amount of seed development took place while the seeds were in the windrow. Seed weight of tall fescue harvested at 51.6% moisture increased from 250.6 to 279.6 mg/ 100 seeds. No increase in seed weight occurred in the other species or windrowing dates. After several days in the windrow, speed of germination increased in all three species. Germination percentage, seedling emergence, and shoot weight did not improve after windrowing. Very little seed deterioration occurred during the first month in the windrow. A perceptible drop in germination of orchardgrass and perennial ryegrass occurred during the 2 weeks prior to the 19 August sampling date. Seed weight declined by the end of the experimental period in all three crops. Some germinated seeds were found in the perennial ryegras windrows by the end of August. No reduction in speed of germination or shoot weight occurred, while there was a trend toward reduced seedling emergence near the end of the experimental period. There were no indications that the stage of maturity when harvested influenced the rate of seed deterioration in the windrow. The probability of seed deterioration occurring at a faster rate than in 1976 is not great since a total of 75.69 mm (2.98 in) of rain fell during the experimental period, compared to a normal rainfall of 27.43 mm (1.08 in). 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• 388. [Article] Fire effects on vegetation diversity, structure, and successional dynamics in shrub-steppe and mixed conifer environments of the Hells Canyon, Idaho

  The effects of fire severity on post-fire succession and shrub demography were quantified in shrub-steppe grasslands and subalpine forests in the Hells Canyon of the Payette National Forest, Idaho. Following ...

  Citation × Citation Citation Abstract Copy Title: Fire effects on vegetation diversity, structure, and successional dynamics in shrub-steppe and mixed conifer environments of the Hells Canyon, Idaho Author: Havlina, Douglas William The effects of fire severity on post-fire succession and shrub demography were quantified in shrub-steppe grasslands and subalpine forests in the Hells Canyon of the Payette National Forest, Idaho. Following the 1988 Eagle Bar Fire, species frequency, community diversity, fire adaptations, and stand ages were quantified at 12 plots in burned and unburned forests. Pre-fire composition was dominated by Pseudotsuga menziesii, Pinus contorta, Abies grandis, and Abies lasiocarpa in the overstory. Prefire basal area ranged from 41 to 80 m 2 ha-1 . Pre-fire stand ages ranged from 71 years in Abies lasiocarpa forests to > 200 years in Pseudotsuga menziesii stands. Fire scenarios which were sampled consisted of: (1) complete stand-replacement fires; (2) partial standreplacement fires; and (3) unburned forests (control). Partial stand-replacement forests were characterized by significantly higher mean species diversity and richness (H'=3.16, S=36) than complete stand-replacement (H'=2.78, S=27) or unburned forests (H=2.26, S=15). Vegetation preferentially established in burned areas along a gradient of fire severity according to adapted fire guilds. Single-storied forests dominated by Pinus contorta and Abies lasiocarpa typified stand-replacement fire scenarios, with mean ages ranging from 99 to 159 years corresponding to fire return intervals common in this type. Multi-storied forests of Pseudotsuga menziesii in the overstory and Abies spp. in the mid-story comprised partial stand-replacement forests. Overstory stand ages ranged from 165 to 209 years, while mid-story ages ranged from 77 to 99 years, corresponding to fire-return intervals which characterize the intermediate, partial stand-replacement fire regime. In the Hells Canyon forests, fire is a dominant ecosystem process in the creation of landscape mosaics, in governing species distribution, and in the maintenance of biological diversity. Forests experiencing complete stand-replacement (n=4) were dominated by Salix scouleriana, a classic off-site colonizer. At the fourth post-fire year, Salix scouleriana density ranged from 252,000 shrubs ha' to 569,333 shrubs ha-1 . From the fourth to the fifth post-fire year, mean shrub density showed a significant decrease from 336,667 to 246,000 shrubs ha.4 . During this same period, mean shrub biomass significantly increased from 10.2 g shrub-1 to 33.1 g shrub"', mean aboveground biomass significantly increased from 2.95 to 7.05 Mg ha-1, and mean shrub height significantly increased from 62 to 100 cm shrub-1. Without competing conifers, Salix scouleriana may maintain site dominance for several decades. The 1992 Windy Ridge Fire burned approximately 2,000 ha of the Purshia tridentatal Agropyron spicatum plant association at elevations < 1460 m. Because Purshia tridentata survivorship appeared to be associated with plant age and ecotype, a multiple regression model was developed to partition burned and unburned shrubs into age class segments at n=10 sites. Pre-fire shrub density ranged from 400 to 1700 shrubs ha-1. Concomitant with Purshia tridentata decadence and stagnation following a lengthened fire-free interval were increases in post-fire mortality. Post-fire mortality of Purshia tridentata was closely associated with plant age (R2=0.91). Plants in age classes < 25 years of age exhibited 66% sprouting, while shrubs > 25 years of age had only 20% survival. Shrub mortality in burned communities ranged from 37% to 100%, while mortality among unburned communities averaged 5%. The reintroduction of fire appears to be a necessity for restoring certain Purshia tridentata ecotypes which have not entered stagnation. Continued fire exclusion may well result in the loss of many at risk Purshia tridentata communities. As an influence on ecosystem function, genetic variation, and landscape mosaics, fire represents a pervasive disturbance in the Hells Canyon ecosystems. Unique successional pathways result from fires which vary in dimension, severity, and periodicity, thereby contributing to diversity at all scales. Intrinsic adaptations to fire testify to the coevolution between flora and fire in the Hells Canyon, and illustrate the resiliency of biota in fire-dominated environments. Title: Fire effects on vegetation diversity, structure, and successional dynamics in shrub-steppe and mixed conifer environments of the Hells Canyon, Idaho Author: Havlina, Douglas William The effects of fire severity on post-fire succession and shrub demography were quantified in shrub-steppe grasslands and subalpine forests in the Hells Canyon of the Payette National Forest, Idaho. Following the 1988 Eagle Bar Fire, species frequency, community diversity, fire adaptations, and stand ages were quantified at 12 plots in burned and unburned forests. Pre-fire composition was dominated by Pseudotsuga menziesii, Pinus contorta, Abies grandis, and Abies lasiocarpa in the overstory. Prefire basal area ranged from 41 to 80 m 2 ha-1 . Pre-fire stand ages ranged from 71 years in Abies lasiocarpa forests to > 200 years in Pseudotsuga menziesii stands. Fire scenarios which were sampled consisted of: (1) complete stand-replacement fires; (2) partial standreplacement fires; and (3) unburned forests (control). Partial stand-replacement forests were characterized by significantly higher mean species diversity and richness (H'=3.16, S=36) than complete stand-replacement (H'=2.78, S=27) or unburned forests (H=2.26, S=15). Vegetation preferentially established in burned areas along a gradient of fire severity according to adapted fire guilds. Single-storied forests dominated by Pinus contorta and Abies lasiocarpa typified stand-replacement fire scenarios, with mean ages ranging from 99 to 159 years corresponding to fire return intervals common in this type. Multi-storied forests of Pseudotsuga menziesii in the overstory and Abies spp. in the mid-story comprised partial stand-replacement forests. Overstory stand ages ranged from 165 to 209 years, while mid-story ages ranged from 77 to 99 years, corresponding to fire-return intervals which characterize the intermediate, partial stand-replacement fire regime. In the Hells Canyon forests, fire is a dominant ecosystem process in the creation of landscape mosaics, in governing species distribution, and in the maintenance of biological diversity. Forests experiencing complete stand-replacement (n=4) were dominated by Salix scouleriana, a classic off-site colonizer. At the fourth post-fire year, Salix scouleriana density ranged from 252,000 shrubs ha' to 569,333 shrubs ha-1 . From the fourth to the fifth post-fire year, mean shrub density showed a significant decrease from 336,667 to 246,000 shrubs ha.4 . During this same period, mean shrub biomass significantly increased from 10.2 g shrub-1 to 33.1 g shrub"', mean aboveground biomass significantly increased from 2.95 to 7.05 Mg ha-1, and mean shrub height significantly increased from 62 to 100 cm shrub-1. Without competing conifers, Salix scouleriana may maintain site dominance for several decades. The 1992 Windy Ridge Fire burned approximately 2,000 ha of the Purshia tridentatal Agropyron spicatum plant association at elevations < 1460 m. Because Purshia tridentata survivorship appeared to be associated with plant age and ecotype, a multiple regression model was developed to partition burned and unburned shrubs into age class segments at n=10 sites. Pre-fire shrub density ranged from 400 to 1700 shrubs ha-1. Concomitant with Purshia tridentata decadence and stagnation following a lengthened fire-free interval were increases in post-fire mortality. Post-fire mortality of Purshia tridentata was closely associated with plant age (R2=0.91). Plants in age classes < 25 years of age exhibited 66% sprouting, while shrubs > 25 years of age had only 20% survival. Shrub mortality in burned communities ranged from 37% to 100%, while mortality among unburned communities averaged 5%. The reintroduction of fire appears to be a necessity for restoring certain Purshia tridentata ecotypes which have not entered stagnation. Continued fire exclusion may well result in the loss of many at risk Purshia tridentata communities. As an influence on ecosystem function, genetic variation, and landscape mosaics, fire represents a pervasive disturbance in the Hells Canyon ecosystems. Unique successional pathways result from fires which vary in dimension, severity, and periodicity, thereby contributing to diversity at all scales. Intrinsic adaptations to fire testify to the coevolution between flora and fire in the Hells Canyon, and illustrate the resiliency of biota in fire-dominated environments. Close

• 389. [Image] A guide to Oregon permits issued by state & federal agencies with a focus on permits for watershed restoration activities Watersheds and the Oregon Watershed Enhancement Board

  	"Spring 2000."
  	Citation × Citation Citation Abstract Copy Title: A guide to Oregon permits issued by state & federal agencies with a focus on permits for watershed restoration activities Watersheds and the Oregon Watershed Enhancement Board Year: 2000, 2005 "Spring 2000." Title: A guide to Oregon permits issued by state & federal agencies with a focus on permits for watershed restoration activities Watersheds and the Oregon Watershed Enhancement Board Year: 2000, 2005 "Spring 2000." Close

• 390. [Article] Road networks, timber harvest, and the spread of Phytophthora root rot infestations of Port-Orford-­cedar in southwest Oregon

  Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree ...

  Citation × Citation Citation Abstract Copy Title: Road networks, timber harvest, and the spread of Phytophthora root rot infestations of Port-Orford-­cedar in southwest Oregon Author: Clark, William C. Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree species of ecological, economical, and cultural importance to coastal Oregon and California. Local scale distribution of P. lateralis is thought to be associated with timber harvest and road-building disturbances. However, knowledge of the landscape-scale factors that contribute to successful invasions of P. lateralis is also important for effective land management of Port-Orford-cedar. P. lateralis is able to infest in wet conditions via stream networks (zoospore) and dry conditions via road networks (resting spore). This study tested the hypothesis that vehicles spread P. lateralis by relating its distribution to traffic intensive, anthropogenic disturbances (i.e. a road network, timber harvest) over a 31-yr period in a 3,910-km² portion of the Rogue River-Siskiyou National Forest in the Siskiyou Mountains of Oregon. Indices of road disturbance (presence/absence, configuration, length, density, road-stream network connectivity) and timber harvest (presence/absence, area, density, frequency) were related to locations of infested cedar populations from a USFS survey dataset using a geographic information system (GIS). About 40% of 934 7th-field catchments were infested with the pathogen. Total road length of the study site was 5,070 km; maximum road density was 8.2 km/km2 and averaged 1.6 km/km² in roaded catchments (n = 766). Timber activities extracted 17,370 ha (2,338 cutting units) of forest across 509 catchments; 345 catchments were cut ≥ twice. Maximum harvest density was 0.92 km²/km² ([mean] = 0.04). Both road networks and timber harvest patchworks were significantly related to cedar root rot heterogeneity. Chi-squared contingency tables showed that infestation rates were 2.2 times higher in catchments with roads compared to roadless catchments and 1.4 times higher in catchments with road-stream intersections compared to those that were unconnected. Infestation was twice as likely in catchments with both harvest and road presence than road presence alone. Single-variable logistic regression showed that a one percent increase in harvest density increased infestation odds 25% and a one-unit (km/km²) increase in road density increased infestation odds 80%. Road and stream network configuration was also important to pathogen distribution: 1) uninfested catchments are most likely to be spatially removed from infested, roaded catchments, 2) only 11% of 287 roaded catchments downstream of infested, roaded catchments were uninfested, and 3) only 12% of 319 catchments downstream of infested catchments were uninfested. Road networks and timber harvest patchworks appear to reduce landscape heterogeneity by providing up-catchment and down-catchment access to host populations by linking pathogenic materials to the stream network. Timber harvest data suggest that while infestation risk to Port-Orford-cedar populations remains high, management policies may have curbed infestation risk in timber-harvested catchments; if this is a result of specific P. lateralis mitigation policies adopted in the late 1980's or broader, region-wide conservation policies (i.e. the Northwest Forest Plan) is yet unclear. Title: Road networks, timber harvest, and the spread of Phytophthora root rot infestations of Port-Orford-­cedar in southwest Oregon Author: Clark, William C. Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree species of ecological, economical, and cultural importance to coastal Oregon and California. Local scale distribution of P. lateralis is thought to be associated with timber harvest and road-building disturbances. However, knowledge of the landscape-scale factors that contribute to successful invasions of P. lateralis is also important for effective land management of Port-Orford-cedar. P. lateralis is able to infest in wet conditions via stream networks (zoospore) and dry conditions via road networks (resting spore). This study tested the hypothesis that vehicles spread P. lateralis by relating its distribution to traffic intensive, anthropogenic disturbances (i.e. a road network, timber harvest) over a 31-yr period in a 3,910-km² portion of the Rogue River-Siskiyou National Forest in the Siskiyou Mountains of Oregon. Indices of road disturbance (presence/absence, configuration, length, density, road-stream network connectivity) and timber harvest (presence/absence, area, density, frequency) were related to locations of infested cedar populations from a USFS survey dataset using a geographic information system (GIS). About 40% of 934 7th-field catchments were infested with the pathogen. Total road length of the study site was 5,070 km; maximum road density was 8.2 km/km2 and averaged 1.6 km/km² in roaded catchments (n = 766). Timber activities extracted 17,370 ha (2,338 cutting units) of forest across 509 catchments; 345 catchments were cut ≥ twice. Maximum harvest density was 0.92 km²/km² ([mean] = 0.04). Both road networks and timber harvest patchworks were significantly related to cedar root rot heterogeneity. Chi-squared contingency tables showed that infestation rates were 2.2 times higher in catchments with roads compared to roadless catchments and 1.4 times higher in catchments with road-stream intersections compared to those that were unconnected. Infestation was twice as likely in catchments with both harvest and road presence than road presence alone. Single-variable logistic regression showed that a one percent increase in harvest density increased infestation odds 25% and a one-unit (km/km²) increase in road density increased infestation odds 80%. Road and stream network configuration was also important to pathogen distribution: 1) uninfested catchments are most likely to be spatially removed from infested, roaded catchments, 2) only 11% of 287 roaded catchments downstream of infested, roaded catchments were uninfested, and 3) only 12% of 319 catchments downstream of infested catchments were uninfested. Road networks and timber harvest patchworks appear to reduce landscape heterogeneity by providing up-catchment and down-catchment access to host populations by linking pathogenic materials to the stream network. Timber harvest data suggest that while infestation risk to Port-Orford-cedar populations remains high, management policies may have curbed infestation risk in timber-harvested catchments; if this is a result of specific P. lateralis mitigation policies adopted in the late 1980's or broader, region-wide conservation policies (i.e. the Northwest Forest Plan) is yet unclear. Close