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• 71. [Article] Markets, Pooling and Insurance for Managing Incidental Catch In Fisheries

  Abstract only.

  Citation × Citation Citation Abstract Copy Title: Markets, Pooling and Insurance for Managing Incidental Catch In Fisheries Author: Holland, Dan Abstract only. Title: Markets, Pooling and Insurance for Managing Incidental Catch In Fisheries Author: Holland, Dan Abstract only. Close

• 72. [Article] A survey of scale insects (Sternorryncha: Coccoidea) occurring on table grapes in South Africa

  Increasing international trade and tourism have led to an increase in the introduction of exotic pests that pose a considerable economic threat to the agro-ecosystems of importing countries. Scale insects ...

  Citation × Citation Citation Abstract Copy Title: A survey of scale insects (Sternorryncha: Coccoidea) occurring on table grapes in South Africa Author: Krüger, Kerstin, Saccaggi, Davina L., Millar, Ian M., Walton, Vaughn M. Increasing international trade and tourism have led to an increase in the introduction of exotic pests that pose a considerable economic threat to the agro-ecosystems of importing countries. Scale insects (Sternorryncha: Coccoidea) may be contaminants of export consignments from the South African deciduous fruit industry to the European Union, Israel, United Kingdom and the United States, for example. Infestations of immature scale insects found on South African fruit destined for export have resulted in increasing rates of rejection of such consignments. To identify the risk posed by scale insect species listed as phytosanitary pests on table grapes to the abovementioned importing countries, a field survey was undertaken in 2004–2005 in vineyards throughout all grape-producing regions in South Africa. Coccoidea species found during the current field survey were Planococcus ficus (Signoret), Pseudococcus longispinus (Targioni Tozzetti), Coccus hesperidum L. and Nipaecoccus viridis (Newstead). With the exception of Pl. ficus, which has only been collected from Vitis vinifera (Vitaceae) and Ficus carica (Moraceae) in South Africa, these species are polyphagous and have a wide host range. None of the scale insect species found to occur in vineyards in South Africa pose a phytosanitary risk to countries where fruit are exported except for Ferrisia malvastra (McDaniel) and N. viridis that have not been recorded in the USA. All scale insects previously found in vineyards in South Africa are listed and their phytosanitary status discussed. The results of the survey show that the risk of exporting scale insect pests of phytosanitary importance on table grapes from South Africa is limited. Title: A survey of scale insects (Sternorryncha: Coccoidea) occurring on table grapes in South Africa Author: Krüger, Kerstin, Saccaggi, Davina L., Millar, Ian M., Walton, Vaughn M. Increasing international trade and tourism have led to an increase in the introduction of exotic pests that pose a considerable economic threat to the agro-ecosystems of importing countries. Scale insects (Sternorryncha: Coccoidea) may be contaminants of export consignments from the South African deciduous fruit industry to the European Union, Israel, United Kingdom and the United States, for example. Infestations of immature scale insects found on South African fruit destined for export have resulted in increasing rates of rejection of such consignments. To identify the risk posed by scale insect species listed as phytosanitary pests on table grapes to the abovementioned importing countries, a field survey was undertaken in 2004–2005 in vineyards throughout all grape-producing regions in South Africa. Coccoidea species found during the current field survey were Planococcus ficus (Signoret), Pseudococcus longispinus (Targioni Tozzetti), Coccus hesperidum L. and Nipaecoccus viridis (Newstead). With the exception of Pl. ficus, which has only been collected from Vitis vinifera (Vitaceae) and Ficus carica (Moraceae) in South Africa, these species are polyphagous and have a wide host range. None of the scale insect species found to occur in vineyards in South Africa pose a phytosanitary risk to countries where fruit are exported except for Ferrisia malvastra (McDaniel) and N. viridis that have not been recorded in the USA. All scale insects previously found in vineyards in South Africa are listed and their phytosanitary status discussed. The results of the survey show that the risk of exporting scale insect pests of phytosanitary importance on table grapes from South Africa is limited. Close

• 73. [Article] Long-Term Health Effects, Risk Perceptions, and Consumption Patterns for Aquacultured Seafood

  Presentation

  Citation × Citation Citation Abstract Copy Title: Long-Term Health Effects, Risk Perceptions, and Consumption Patterns for Aquacultured Seafood Author: Uchida, Hirotsugu, Johnston, Roberty, Roheim, Cathy Presentation Title: Long-Term Health Effects, Risk Perceptions, and Consumption Patterns for Aquacultured Seafood Author: Uchida, Hirotsugu, Johnston, Roberty, Roheim, Cathy Presentation Close

• 74. [Article] The impact hazard.

  48 pages

  Citation × Citation Citation Abstract Copy Title: The impact hazard. Author: Morrison, David, Chapman, Clark R., Slovic, Paul Year: 2017, 1994 48 pages Title: The impact hazard. Author: Morrison, David, Chapman, Clark R., Slovic, Paul Year: 2017, 1994 48 pages Close

• 75. [Article] Marine, Estuarine, and Diadromous Fish Stocks at Risk of Extinction in North America (Exclusive of Pacific Salmonids)

  The problem of extinction in the sea has been recognized only recently by the scientific community (Roberts and Hawkins 1999). For the last decade, the American Fisheries Society (AFS) has pursued an initiative ...

  Citation × Citation Citation Abstract Copy Title: Marine, Estuarine, and Diadromous Fish Stocks at Risk of Extinction in North America (Exclusive of Pacific Salmonids) Author: Sala, E., Musick, J.A., Gilmore, R.G., Sedberry, G.R., Harbin, M.M., McGovern, J.C., Poss, S.G., Weeks, H., Parker, S.J., Schmidt, T.W., Burgess, G.H., Eklund, A.M., Golden, J.T., Ha, D.S., Findley, L., Berkeley, S.A., Huntsman, G.R., Wright, S.G. The problem of extinction in the sea has been recognized only recently by the scientific community (Roberts and Hawkins 1999). For the last decade, the American Fisheries Society (AFS) has pursued an initiative to identify marine fish stocks that may be at risk of extinction in North America (Musick 1998; Coleman et al. 2000; Musick et al. 2000a; Musick et al. 2000b; Parker et al. 2000). The present paper presents the first recognized AFS list of marine, estuarine, and diadromous fishes that may be at risk of extinction in North America (exclusive of Pacific salmonids). The geographic scope of this review includes the coastal waters of Mexico, the continental United States, Alaska, and Canada. The objectives in preparing this list have been to identify stocks at risk at a sufficiently early stage of decline to avoid listing as threatened or endangered, minimize the probability of under- or overestimating the risk of extinction, use the best existing knowledge of stock dynamics at low population levels, and allow experts on stocks to bring to bear all the available knowledge about life history and conservation status in order to categorize risk of extinction. Title: Marine, Estuarine, and Diadromous Fish Stocks at Risk of Extinction in North America (Exclusive of Pacific Salmonids) Author: Sala, E., Musick, J.A., Gilmore, R.G., Sedberry, G.R., Harbin, M.M., McGovern, J.C., Poss, S.G., Weeks, H., Parker, S.J., Schmidt, T.W., Burgess, G.H., Eklund, A.M., Golden, J.T., Ha, D.S., Findley, L., Berkeley, S.A., Huntsman, G.R., Wright, S.G. The problem of extinction in the sea has been recognized only recently by the scientific community (Roberts and Hawkins 1999). For the last decade, the American Fisheries Society (AFS) has pursued an initiative to identify marine fish stocks that may be at risk of extinction in North America (Musick 1998; Coleman et al. 2000; Musick et al. 2000a; Musick et al. 2000b; Parker et al. 2000). The present paper presents the first recognized AFS list of marine, estuarine, and diadromous fishes that may be at risk of extinction in North America (exclusive of Pacific salmonids). The geographic scope of this review includes the coastal waters of Mexico, the continental United States, Alaska, and Canada. The objectives in preparing this list have been to identify stocks at risk at a sufficiently early stage of decline to avoid listing as threatened or endangered, minimize the probability of under- or overestimating the risk of extinction, use the best existing knowledge of stock dynamics at low population levels, and allow experts on stocks to bring to bear all the available knowledge about life history and conservation status in order to categorize risk of extinction. Close

• 76. [Article] Reproductive isolation and interspecific hybridization in the threatened species, Sidalcea nelsoniana

  In addition to its longstanding recognition as an influential evolutionary process, interspecific hybridization is increasingly regarded as a potential threat to the genetic integrity and survival of rare ...

  Citation × Citation Citation Abstract Copy Title: Reproductive isolation and interspecific hybridization in the threatened species, Sidalcea nelsoniana Author: Gisler, Steven D. In addition to its longstanding recognition as an influential evolutionary process, interspecific hybridization is increasingly regarded as a potential threat to the genetic integrity and survival of rare plant species, manifested through gamete wasting, increased pest and disease pressures, outbreeding depression, competitive exclusion, and genetic assimilation. Alternatively, hybridization has also been interpreted as a theoretically beneficial process for rare species suffering from low adaptive genetic diversity and accumulated genetic load. As such, interspecific hybridization, and the underlying pre- and post-mating reproductive barriers that influence its progression, should be considered fundamental components of conservation planning for many rare species, particularly those predisposed to hybridization by various ecological, genetic, and anthropogenic risk factors. In this study I evaluate the nature and efficacy of preand post-mating hybridization barriers in the threatened species, Sidalcea nelsoniana, which is sympatric (or nearly so) with three other congeners in the scarce native grasslands of the Willamette Valley in western Oregon. These four perennial species share a high risk of hybridization due to their mutual proximity, common occupation of disturbed habitats, susceptibility to anthropogenic dispersal, predominantly outcrossing mating systems, their capability of longlived persistence and vegetative expansion, and demonstrated hybridization tendencies among other members of the family and genus. Results show S. nelsoniana is reproductively isolated from all three of its congeners by a complex interplay of pre- and post-mating barriers. Although S. nelsoniana overlaps with S. campestris in the ecological attributes of flowering time, fine-scale geographic distribution, and pollinators, interspecific hybridization is discouraged through the post-mating barrier of sexual incompatibility (expressed primarily as reduced seed set). Hybridization between S. nelsoniana and S. virgata is limited by the premating barrier of asynchronous flowering (temporal isolation) and the supplemental post-mating barrier of sexual incompatibility, though the completeness of the latter varies in relation to crossing direction and S. virgata phenotype. Lastly, although S. nelsoniana and S. cusickii exhibit full interspecific sexual compatibility and produce fully fertile hybrids, hybridization in this species pair is discouraged by the pre-mating barrier of geographic isolation (the two species are narrowly parapatric). Additional findings of this study show that 1) pollinators transferred significantly more S. nelsoniana pollen to the heterospecific flowers of S. virgata and S. cusickii than to conspecific flowers (or those of S. campestris) in a mixed species array, 2) anthropogenic disturbance is ubiquitous across extant S. nelsoniana study populations so cannot be conclusively linked with the breakdown of spatial reproductive barriers, 3) polyploidy is confirmed in the species group and appears to directly influence the observed patterns of interspecific sexual compatibility and the chromosome numbers of hybrids, and 4) Fl hybrids exhibit a mosaic of parental, intermediate, and transgressive phenotypic characters that render hybrid discrimination difficult (especially in light of pronounced parental phenotypic variability). Ultimately, despite the presence of pre- and post-mating reproductive barriers, hybridization between Sidalcea nelsoniana and its local congeners is still possible through human intervention. Preserving the species' current genetic integrity will require prevention of Sidalcea dispersal that could lead to the breakdown of spatial, temporal, and sexual barriers between species. Development of useful molecular markers will be needed to help recognize hybrids in the wild, as traditional morphological methods appear inadequate for this endeavor. Title: Reproductive isolation and interspecific hybridization in the threatened species, Sidalcea nelsoniana Author: Gisler, Steven D. In addition to its longstanding recognition as an influential evolutionary process, interspecific hybridization is increasingly regarded as a potential threat to the genetic integrity and survival of rare plant species, manifested through gamete wasting, increased pest and disease pressures, outbreeding depression, competitive exclusion, and genetic assimilation. Alternatively, hybridization has also been interpreted as a theoretically beneficial process for rare species suffering from low adaptive genetic diversity and accumulated genetic load. As such, interspecific hybridization, and the underlying pre- and post-mating reproductive barriers that influence its progression, should be considered fundamental components of conservation planning for many rare species, particularly those predisposed to hybridization by various ecological, genetic, and anthropogenic risk factors. In this study I evaluate the nature and efficacy of preand post-mating hybridization barriers in the threatened species, Sidalcea nelsoniana, which is sympatric (or nearly so) with three other congeners in the scarce native grasslands of the Willamette Valley in western Oregon. These four perennial species share a high risk of hybridization due to their mutual proximity, common occupation of disturbed habitats, susceptibility to anthropogenic dispersal, predominantly outcrossing mating systems, their capability of longlived persistence and vegetative expansion, and demonstrated hybridization tendencies among other members of the family and genus. Results show S. nelsoniana is reproductively isolated from all three of its congeners by a complex interplay of pre- and post-mating barriers. Although S. nelsoniana overlaps with S. campestris in the ecological attributes of flowering time, fine-scale geographic distribution, and pollinators, interspecific hybridization is discouraged through the post-mating barrier of sexual incompatibility (expressed primarily as reduced seed set). Hybridization between S. nelsoniana and S. virgata is limited by the premating barrier of asynchronous flowering (temporal isolation) and the supplemental post-mating barrier of sexual incompatibility, though the completeness of the latter varies in relation to crossing direction and S. virgata phenotype. Lastly, although S. nelsoniana and S. cusickii exhibit full interspecific sexual compatibility and produce fully fertile hybrids, hybridization in this species pair is discouraged by the pre-mating barrier of geographic isolation (the two species are narrowly parapatric). Additional findings of this study show that 1) pollinators transferred significantly more S. nelsoniana pollen to the heterospecific flowers of S. virgata and S. cusickii than to conspecific flowers (or those of S. campestris) in a mixed species array, 2) anthropogenic disturbance is ubiquitous across extant S. nelsoniana study populations so cannot be conclusively linked with the breakdown of spatial reproductive barriers, 3) polyploidy is confirmed in the species group and appears to directly influence the observed patterns of interspecific sexual compatibility and the chromosome numbers of hybrids, and 4) Fl hybrids exhibit a mosaic of parental, intermediate, and transgressive phenotypic characters that render hybrid discrimination difficult (especially in light of pronounced parental phenotypic variability). Ultimately, despite the presence of pre- and post-mating reproductive barriers, hybridization between Sidalcea nelsoniana and its local congeners is still possible through human intervention. Preserving the species' current genetic integrity will require prevention of Sidalcea dispersal that could lead to the breakdown of spatial, temporal, and sexual barriers between species. Development of useful molecular markers will be needed to help recognize hybrids in the wild, as traditional morphological methods appear inadequate for this endeavor. Close

• 77. [Article] Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impacts

  In the past, sharks, skates and ray species have mainly occurred in incidental fisheries. Now they are increasingly being directly targeted due to the depleted status of traditionally targeted species. ...

  Citation × Citation Citation Abstract Copy Title: Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impacts Author: Thompson, Josie E. In the past, sharks, skates and ray species have mainly occurred in incidental fisheries. Now they are increasingly being directly targeted due to the depleted status of traditionally targeted species. The life history characteristics of many elasmobranch species make them more sensitive to high rates of fishing mortality. The combination of these factors has resulted in the known local depletion of several elasmobranch species; including the barndoor skate, Raja laevis, of the Northwest Atlantic and the common skate, Raja batis, of Irish Sea. The longnose skate, Raja rhina, occurs commonly as incidental catch in trawl fisheries off the coast of California, Oregon and Washington. Commercial landings of skates, including R. rhina, have increased dramatically along the U.S. West coast. The objectives of this study have been to calculate accurate growth and maturity parameters for Raja rhina in order that the vulnerability of this species to fishing mortality can be assessed. The slow growth rates (k=0.04 to 0.06) and late ages-at-50% maturity (11 to 16 years with maximum ages between 15 and 22 years, depending on sex and region) which were calculated indicate that this species may be at great risk of depletion in the future. Survey biomass trends indicate that R. rhina populations have remained stable over the past twenty years. However, the possibility that biomass levels in the distant past were much higher than they are at present cannot be ruled out. It is recommended that the collection of fishery-dependent data for this species and other skate species begins immediately. This information, along with the results found in this are needed for a proper assessment for Raja rhina, so that the effects of current fishing pressures can be evaluated and regulated appropriately. Title: Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impacts Author: Thompson, Josie E. In the past, sharks, skates and ray species have mainly occurred in incidental fisheries. Now they are increasingly being directly targeted due to the depleted status of traditionally targeted species. The life history characteristics of many elasmobranch species make them more sensitive to high rates of fishing mortality. The combination of these factors has resulted in the known local depletion of several elasmobranch species; including the barndoor skate, Raja laevis, of the Northwest Atlantic and the common skate, Raja batis, of Irish Sea. The longnose skate, Raja rhina, occurs commonly as incidental catch in trawl fisheries off the coast of California, Oregon and Washington. Commercial landings of skates, including R. rhina, have increased dramatically along the U.S. West coast. The objectives of this study have been to calculate accurate growth and maturity parameters for Raja rhina in order that the vulnerability of this species to fishing mortality can be assessed. The slow growth rates (k=0.04 to 0.06) and late ages-at-50% maturity (11 to 16 years with maximum ages between 15 and 22 years, depending on sex and region) which were calculated indicate that this species may be at great risk of depletion in the future. Survey biomass trends indicate that R. rhina populations have remained stable over the past twenty years. However, the possibility that biomass levels in the distant past were much higher than they are at present cannot be ruled out. It is recommended that the collection of fishery-dependent data for this species and other skate species begins immediately. This information, along with the results found in this are needed for a proper assessment for Raja rhina, so that the effects of current fishing pressures can be evaluated and regulated appropriately. Close

• 78. [Article] Oregon Dreissenid Mussel: Rapid Response Plan

  In 2007, both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) were found to have established populations west of the Rocky Mountains. The risk posed to the Pacific ...

  Citation × Citation Citation Abstract Copy Title: Oregon Dreissenid Mussel: Rapid Response Plan Author: Draheim, Robyn, Boatner, Rick, Dolphin, Glenn, DeBruyckere, Lisa Year: 2013 In 2007, both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) were found to have established populations west of the Rocky Mountains. The risk posed to the Pacific Northwest by the proximity of these new infestations is significant. This plan was developed in response to the increasing likelihood of the successful transport and introduction of these species into the State of Oregon and Pacific Northwest. Although prevention remains the most cost-effective means of addressing potential infestations of aquatic invasive species, if prevention efforts fail, the State of Oregon must be prepared to respond rapidly and effectively to minimize environmental and economic impacts and reduce the risk of spread. The purpose of this plan is to protect Oregon’s waters, aquatic resources, and facilities from the deleterious effects of Dreissenid mussel establishment. This plan serves as a guidance document for natural resource managers to plan for and provide a rapid response effort to a Dreissenid mussel infestation in Oregon waters. This plan is intended to complement the Columbia River Basin Interagency Invasive Species Response Plan: Zebra Mussels and Other Dreissena Species drafted by the Columbia River Basin 100th Meridian Team as well as provide stand-alone guidance should mussels be found in Oregon but outside of the Columbia River Basin. This plan applies to all Dreissenid mussels, although the current focus is on zebra and quagga mussels. Many of the strategies listed herein can be applied to rapid response efforts for other aquatic invasive species (AIS) of concern. Title: Oregon Dreissenid Mussel: Rapid Response Plan Author: Draheim, Robyn, Boatner, Rick, Dolphin, Glenn, DeBruyckere, Lisa Year: 2013 In 2007, both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) were found to have established populations west of the Rocky Mountains. The risk posed to the Pacific Northwest by the proximity of these new infestations is significant. This plan was developed in response to the increasing likelihood of the successful transport and introduction of these species into the State of Oregon and Pacific Northwest. Although prevention remains the most cost-effective means of addressing potential infestations of aquatic invasive species, if prevention efforts fail, the State of Oregon must be prepared to respond rapidly and effectively to minimize environmental and economic impacts and reduce the risk of spread. The purpose of this plan is to protect Oregon’s waters, aquatic resources, and facilities from the deleterious effects of Dreissenid mussel establishment. This plan serves as a guidance document for natural resource managers to plan for and provide a rapid response effort to a Dreissenid mussel infestation in Oregon waters. This plan is intended to complement the Columbia River Basin Interagency Invasive Species Response Plan: Zebra Mussels and Other Dreissena Species drafted by the Columbia River Basin 100th Meridian Team as well as provide stand-alone guidance should mussels be found in Oregon but outside of the Columbia River Basin. This plan applies to all Dreissenid mussels, although the current focus is on zebra and quagga mussels. Many of the strategies listed herein can be applied to rapid response efforts for other aquatic invasive species (AIS) of concern. Close

• 79. [Article] Performance of Willamette Valley native plants following herbicide exposure

  Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than ...

  Citation × Citation Citation Abstract Copy Title: Performance of Willamette Valley native plants following herbicide exposure Author: Blakeley-Smith, Matthew R. Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than 1% of their historical area. The remnant prairies that persist today are small in size and are highly fragmented. Marginal strips of habitat along roadsides and agricultural fields play an important role as refugia for native species and provide important resources for wildlife. These seemingly insignificant habitat units may also play an important role in facilitating gene flow between disjunct populations of prairie plants, thus reducing the potential for the negative effects of inbreeding depression. Presently, much of the land area in the Willamette Valley is dedicated to commercial agricultural which is heavily reliant on herbicides for weed control and field preparation. Since herbicide applications are imprecise and prone to drift, there is potential to impact the native plants surrounding these agricultural fields. Current EPA methods for assessing the ecological effects of herbicides may not be robust enough to account for potential impacts on native plants since the suggested test species are ten annual agricultural crops. To address the need for improved phytotoxicity testing protocols, we incorporated non-crop plant species into the EPA vegetative vigor test methodology for use in determining effects of low concentrations of chemical herbicides on Willamette Valley terrestrial plants. A separate experiment was conducted in order to determine how herbicides might be used to restore Butterfly Meadows, a degraded Willamette Valley prairie. The specific objective of this study were to: 1.) determine which herbicide treatments were most effective at reducing dominance of an invasive species, Brachypodium sylvaticum, 2.) determine if native species declined following herbicide treatments, and 3.) describe the compositional changes in the plant communities over a four-year period. The EPA vegetative vigor test study showed that there was a wide variety of responses among 17 species (14 native and 3 introduced) to each herbicide tested (glyphosate, tribenuron, and fluazifop). For glyphosate, Potentilla gracilis was the most sensitive species based on an EC25 value of 0.012 x f.a.r. for dry weight; while Bromus carinatus, Clarkia amoena, Gilia capitata, and Lupinus albicaulis were tolerant to glyphosate as indicated by no effect on dry weight. Seven Willamette Valley forb species were sensitive to tribenuron based on EC25 values ranging from 0.001 to 0.012 x f.a.r.; Clarkia amoena, Collinsia grandflora, Leucanthemum vulgare, Potentilla gracilis, Prunella vulgaris, Ranunculus occidentalis and Sanquisorba occidentalis. Six grass species and Eriophyllum lanatum were resistant to tribenuron showing no reduction in dry weight. Fluazifop primarily affected grass species as expected due to the grass-specific activity for this herbicide. Two native grasses, Elymus trachycaulus and Danthonia californica were the most sensitive to fluazifop, based on low EC25 values of 0.002 to 0.010 x f.a.r. A native fescue grass, Festuca roemeri, and nearly all the forb species were resistant to fluazifop, showing no response at any herbicide rate applied. The results from this research will be useful as background information for evaluating potential modifications in the EPA's Vegetative Vigor Test to assess the risk of herbicides to non-target plants. Seven different herbicide combinations were effective at reducing the cover of Brachypodium sylvaticum in test plots at Butterfly Meadows one year after treatment. The reduction of B. sylvaticum was short lived however, since the cover of this grass species was not different from control plots during the second growing season. Native plant species were not negatively impacted by the herbicide treatments, as shown by MRPP analysis. Successional trajectories illustrate that control plots that were dominated by B. sylvaticum remained relatively unchanged over the course of four years. Some treatments exhibited a sharp decline in dominance by graminoids after the first year, a recovery the second year, but never returned exactly to their pretreatment community composition after the third year. The reduction of the dominant species after the first growing season was associated with colonization by a number of introduced species into the newly created open habitat. Over the same period there was no overall increase in native species cover, suggesting that the native species at this site may be recruitment limited. Future restoration activities at this site should include multiple years of B. sylvaticum control, with special attention to the seed bank and tolerant individuals. Seed additions of native species may help fill empty niches and afford resistance to invasion by introduced species. Title: Performance of Willamette Valley native plants following herbicide exposure Author: Blakeley-Smith, Matthew R. Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than 1% of their historical area. The remnant prairies that persist today are small in size and are highly fragmented. Marginal strips of habitat along roadsides and agricultural fields play an important role as refugia for native species and provide important resources for wildlife. These seemingly insignificant habitat units may also play an important role in facilitating gene flow between disjunct populations of prairie plants, thus reducing the potential for the negative effects of inbreeding depression. Presently, much of the land area in the Willamette Valley is dedicated to commercial agricultural which is heavily reliant on herbicides for weed control and field preparation. Since herbicide applications are imprecise and prone to drift, there is potential to impact the native plants surrounding these agricultural fields. Current EPA methods for assessing the ecological effects of herbicides may not be robust enough to account for potential impacts on native plants since the suggested test species are ten annual agricultural crops. To address the need for improved phytotoxicity testing protocols, we incorporated non-crop plant species into the EPA vegetative vigor test methodology for use in determining effects of low concentrations of chemical herbicides on Willamette Valley terrestrial plants. A separate experiment was conducted in order to determine how herbicides might be used to restore Butterfly Meadows, a degraded Willamette Valley prairie. The specific objective of this study were to: 1.) determine which herbicide treatments were most effective at reducing dominance of an invasive species, Brachypodium sylvaticum, 2.) determine if native species declined following herbicide treatments, and 3.) describe the compositional changes in the plant communities over a four-year period. The EPA vegetative vigor test study showed that there was a wide variety of responses among 17 species (14 native and 3 introduced) to each herbicide tested (glyphosate, tribenuron, and fluazifop). For glyphosate, Potentilla gracilis was the most sensitive species based on an EC25 value of 0.012 x f.a.r. for dry weight; while Bromus carinatus, Clarkia amoena, Gilia capitata, and Lupinus albicaulis were tolerant to glyphosate as indicated by no effect on dry weight. Seven Willamette Valley forb species were sensitive to tribenuron based on EC25 values ranging from 0.001 to 0.012 x f.a.r.; Clarkia amoena, Collinsia grandflora, Leucanthemum vulgare, Potentilla gracilis, Prunella vulgaris, Ranunculus occidentalis and Sanquisorba occidentalis. Six grass species and Eriophyllum lanatum were resistant to tribenuron showing no reduction in dry weight. Fluazifop primarily affected grass species as expected due to the grass-specific activity for this herbicide. Two native grasses, Elymus trachycaulus and Danthonia californica were the most sensitive to fluazifop, based on low EC25 values of 0.002 to 0.010 x f.a.r. A native fescue grass, Festuca roemeri, and nearly all the forb species were resistant to fluazifop, showing no response at any herbicide rate applied. The results from this research will be useful as background information for evaluating potential modifications in the EPA's Vegetative Vigor Test to assess the risk of herbicides to non-target plants. Seven different herbicide combinations were effective at reducing the cover of Brachypodium sylvaticum in test plots at Butterfly Meadows one year after treatment. The reduction of B. sylvaticum was short lived however, since the cover of this grass species was not different from control plots during the second growing season. Native plant species were not negatively impacted by the herbicide treatments, as shown by MRPP analysis. Successional trajectories illustrate that control plots that were dominated by B. sylvaticum remained relatively unchanged over the course of four years. Some treatments exhibited a sharp decline in dominance by graminoids after the first year, a recovery the second year, but never returned exactly to their pretreatment community composition after the third year. The reduction of the dominant species after the first growing season was associated with colonization by a number of introduced species into the newly created open habitat. Over the same period there was no overall increase in native species cover, suggesting that the native species at this site may be recruitment limited. Future restoration activities at this site should include multiple years of B. sylvaticum control, with special attention to the seed bank and tolerant individuals. Seed additions of native species may help fill empty niches and afford resistance to invasion by introduced species. Close

• 80. [Article] Synchytrium endobioticum (Schilb.) percival : pest risk assessment for Oregon

  This archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.

  Citation × Citation Citation Abstract Copy Title: Synchytrium endobioticum (Schilb.) percival : pest risk assessment for Oregon Year: 2010 This archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes. Title: Synchytrium endobioticum (Schilb.) percival : pest risk assessment for Oregon Year: 2010 This archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes. Close