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• 1. [Article] Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane ecosystem

  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 article is copyrighted by International Association ...

  Citation × Citation Citation Abstract Copy Title: Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane ecosystem Author: Andersen, Kelly M., Endress, Bryan A., Parks, Catherine G., Naylor, Bridgett J. 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 article is copyrighted by International Association for Vegetation Science and published by John Wiley & Sons, Ltd.. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291654-109X Title: Contrasting distribution patterns of invasive and naturalized non-native species along environmental gradients in a semi-arid montane ecosystem Author: Andersen, Kelly M., Endress, Bryan A., Parks, Catherine G., Naylor, Bridgett J. 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 article is copyrighted by International Association for Vegetation Science and published by John Wiley & Sons, Ltd.. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291654-109X Close

• 2. [Article] EndressBryanAnimalRangelandSciResponseNativeVersus.pdf

  Citation × Citation Citation Abstract Copy Title: EndressBryanAnimalRangelandSciResponseNativeVersus.pdf Author: Pekin, Burak K., Endress, Bryan A., Parks, Catherine G., Wisdom, Michael J., Naylor, Bridgett J. Title: EndressBryanAnimalRangelandSciResponseNativeVersus.pdf Author: Pekin, Burak K., Endress, Bryan A., Parks, Catherine G., Wisdom, Michael J., Naylor, Bridgett J. Close

• 3. [Article] EndressBryanAnimalRangelandSciResponseNativeVersus(AppendixS1).pdf

  Citation × Citation Citation Abstract Copy Title: EndressBryanAnimalRangelandSciResponseNativeVersus(AppendixS1).pdf Author: Pekin, Burak K., Endress, Bryan A., Parks, Catherine G., Wisdom, Michael J., Naylor, Bridgett J. Title: EndressBryanAnimalRangelandSciResponseNativeVersus(AppendixS1).pdf Author: Pekin, Burak K., Endress, Bryan A., Parks, Catherine G., Wisdom, Michael J., Naylor, Bridgett J. Close

• 4. [Article] ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess.pdf

  Citation × Citation Citation Abstract Copy Title: ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess.pdf Author: Arismendi, Ivan, Penaluna, Brooke E., et al., Dunham, Jason B. Title: ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess.pdf Author: Arismendi, Ivan, Penaluna, Brooke E., et al., Dunham, Jason B. Close

• 5. [Article] ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess_SupplementalMaterial1.pdf

  Citation × Citation Citation Abstract Copy Title: ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess_SupplementalMaterial1.pdf Author: Arismendi, Ivan, Penaluna, Brooke E., et al., Dunham, Jason B. Title: ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess_SupplementalMaterial1.pdf Author: Arismendi, Ivan, Penaluna, Brooke E., et al., Dunham, Jason B. Close

• 6. [Article] ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess_SupplementalMaterial2.pdf

  Citation × Citation Citation Abstract Copy Title: ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess_SupplementalMaterial2.pdf Author: Arismendi, Ivan, Penaluna, Brooke E., et al., Dunham, Jason B. Title: ArismendiIvanFisheriesWildlifeDifferentialInvasionSuccess_SupplementalMaterial2.pdf Author: Arismendi, Ivan, Penaluna, Brooke E., et al., Dunham, Jason B. Close

• 7. [Article] Non-native and native plant species distributions and variability along an elevation gradient in the Wallowa Mountains, Oregon

  Invasion by non-native plants into natural areas is an important component of global change that threatens biodiversity and ecosystem structure and function. Mountains are currently among the least invaded ...

  Citation × Citation Citation Abstract Copy Title: Non-native and native plant species distributions and variability along an elevation gradient in the Wallowa Mountains, Oregon Author: Averett, Joshua P. Invasion by non-native plants into natural areas is an important component of global change that threatens biodiversity and ecosystem structure and function. Mountains are currently among the least invaded ecosystems, however, these biodiversity hotspots are increasingly under threat of exotic plant invasion. Evaluation of plant species distribution patterns in mountain ecosystems can provide insight into dominant processes of plant invasion and inform management to reduce the spread of non-native plants in mountains. The objectives of this study were to: 1) evaluate the main drivers of plant invasions in the Wallowa Mountain Range of northeastern Oregon, and the extent patterns of native species distributions and their causes differed from non-native species along an elevation gradient; and 2) investigate inter- and intra-annual understory vascular plant species variability along an elevation gradient to inform long-term monitoring of plant invasion dynamics in the Wallowa Mountains. We sampled understory vascular plant communities in summer 2012 along three forest roads in the Wallowa Mountains. Transects (n=20) were evenly stratified by elevation (60 meters) along each road. Indicator species analysis (ISA) was used to identify habitat tendencies for non-native species. Non-metric multidimensional scaling (NMS) related community composition to environmental and species trait factors. Predictors of non-native and native species abundance and richness were evaluated using Non-parametric multiplicative regression (NPMR). Canopy openness and elevation niche widths were modeled for all common species and evaluated for evidence of high elevation or closed canopy specialization. Non-native species richness decreased continuously with increasing elevation. In contrast, native species richness displayed a unimodal distribution with maximum richness at the mid-elevations. According to NMS and NPMR, elevation, canopy openness, and disturbance were the strongest correlates of non-native species abundance. Non-native species were concentrated in low elevation bunchgrass, roadside, and open forest habitats with high canopy openness, and moderate to high disturbance intensity. Overlays of species trait factors onto ordinations revealed that the transition into the subalpine community and over-story canopy closure exceeding approximately 60 percent were potential barriers to non-native species establishment. Vegetation sampling was repeated three times (June, July, and August 2013) during the growing season in summer 2013 for a subset (n=10) of our transects. Blocked Multi Response Permutation Procedure (MRBP) was used to test the hypothesis of no change in species composition between years (summer 2012 and summer 2013) and between each sampling period (June, July, and August) within one growing season. NMS related community composition at different times to environmental and trait category factors. Blocked Indicator Species Analysis was used to identify species with tendencies towards specific sampling periods. Important predictors of vegetation change were identified and indicator species distributions were related to NMS axes using NPMR. Vegetation composition changed both between years and between each sampling period within one growing season. Species richness increased with sampling effort, dominant species were consistently found throughout all sampling periods and rare species showed the highest rate of turnover between sampling periods. The highest species richness and greatest number of indicator species were associated with the early summer (June) sampling period. Approximately 25% of all non-native species showed tendencies towards a specific sampling period where greater than half favored the June sampling period within lowland bunchgrass communities. Annual species including the most dominant non-native species within the lowland and montane zones showed the highest inter- and intra-annual variability compared to other trait categories. Total species richness was positively related to turnover and was the most important predictor of relative abundance change between all sampling periods. Species turnover was highest in species rich montane plots; however, trait abundance and richness did not statistically differ in montane plots. These data suggest that elevation, canopy, openness, and disturbance are important factors structuring non-native plant distributions in the Wallowa Mountains. Our findings that non-native species tended to be concentrated in low elevation, early successional habitats coupled with a lack of high elevation or closed canopy specialization indicates that non-native plants that occurr at the highest elevations are likely generalist species that depend on disturbance (primarily open over-story canopy) for spread into higher elevation sites until they are eventually filtered out by harsh environmental conditions coincident with the subalpine transition zone. Collectively these results suggest that interactions between introduction pathways that favor human assisted dispersal into the low-elevations where ruderal species are favored and environmental filters (elevation, canopy openness, and disturbance) are the dominant factors structuring non-native plant distributions in the Wallowa Mountains. Our results also indicate that long-term monitoring of vegetation change in the Wallowa Mountains will be improved through periodic sampling during each growing season. Sampling once during the spring or early summer and then again coincident with peak biomass should improve estimates of species distributions and diversity patterns by capturing both vernal and late season species. Early season sampling may be particularly important for monitoring non-native plants in the Wallowa Mountains as most non-natives were concentrated in low elevation semiarid bunchgrass communities where spring and early summer specialization is common. Title: Non-native and native plant species distributions and variability along an elevation gradient in the Wallowa Mountains, Oregon Author: Averett, Joshua P. Invasion by non-native plants into natural areas is an important component of global change that threatens biodiversity and ecosystem structure and function. Mountains are currently among the least invaded ecosystems, however, these biodiversity hotspots are increasingly under threat of exotic plant invasion. Evaluation of plant species distribution patterns in mountain ecosystems can provide insight into dominant processes of plant invasion and inform management to reduce the spread of non-native plants in mountains. The objectives of this study were to: 1) evaluate the main drivers of plant invasions in the Wallowa Mountain Range of northeastern Oregon, and the extent patterns of native species distributions and their causes differed from non-native species along an elevation gradient; and 2) investigate inter- and intra-annual understory vascular plant species variability along an elevation gradient to inform long-term monitoring of plant invasion dynamics in the Wallowa Mountains. We sampled understory vascular plant communities in summer 2012 along three forest roads in the Wallowa Mountains. Transects (n=20) were evenly stratified by elevation (60 meters) along each road. Indicator species analysis (ISA) was used to identify habitat tendencies for non-native species. Non-metric multidimensional scaling (NMS) related community composition to environmental and species trait factors. Predictors of non-native and native species abundance and richness were evaluated using Non-parametric multiplicative regression (NPMR). Canopy openness and elevation niche widths were modeled for all common species and evaluated for evidence of high elevation or closed canopy specialization. Non-native species richness decreased continuously with increasing elevation. In contrast, native species richness displayed a unimodal distribution with maximum richness at the mid-elevations. According to NMS and NPMR, elevation, canopy openness, and disturbance were the strongest correlates of non-native species abundance. Non-native species were concentrated in low elevation bunchgrass, roadside, and open forest habitats with high canopy openness, and moderate to high disturbance intensity. Overlays of species trait factors onto ordinations revealed that the transition into the subalpine community and over-story canopy closure exceeding approximately 60 percent were potential barriers to non-native species establishment. Vegetation sampling was repeated three times (June, July, and August 2013) during the growing season in summer 2013 for a subset (n=10) of our transects. Blocked Multi Response Permutation Procedure (MRBP) was used to test the hypothesis of no change in species composition between years (summer 2012 and summer 2013) and between each sampling period (June, July, and August) within one growing season. NMS related community composition at different times to environmental and trait category factors. Blocked Indicator Species Analysis was used to identify species with tendencies towards specific sampling periods. Important predictors of vegetation change were identified and indicator species distributions were related to NMS axes using NPMR. Vegetation composition changed both between years and between each sampling period within one growing season. Species richness increased with sampling effort, dominant species were consistently found throughout all sampling periods and rare species showed the highest rate of turnover between sampling periods. The highest species richness and greatest number of indicator species were associated with the early summer (June) sampling period. Approximately 25% of all non-native species showed tendencies towards a specific sampling period where greater than half favored the June sampling period within lowland bunchgrass communities. Annual species including the most dominant non-native species within the lowland and montane zones showed the highest inter- and intra-annual variability compared to other trait categories. Total species richness was positively related to turnover and was the most important predictor of relative abundance change between all sampling periods. Species turnover was highest in species rich montane plots; however, trait abundance and richness did not statistically differ in montane plots. These data suggest that elevation, canopy, openness, and disturbance are important factors structuring non-native plant distributions in the Wallowa Mountains. Our findings that non-native species tended to be concentrated in low elevation, early successional habitats coupled with a lack of high elevation or closed canopy specialization indicates that non-native plants that occurr at the highest elevations are likely generalist species that depend on disturbance (primarily open over-story canopy) for spread into higher elevation sites until they are eventually filtered out by harsh environmental conditions coincident with the subalpine transition zone. Collectively these results suggest that interactions between introduction pathways that favor human assisted dispersal into the low-elevations where ruderal species are favored and environmental filters (elevation, canopy openness, and disturbance) are the dominant factors structuring non-native plant distributions in the Wallowa Mountains. Our results also indicate that long-term monitoring of vegetation change in the Wallowa Mountains will be improved through periodic sampling during each growing season. Sampling once during the spring or early summer and then again coincident with peak biomass should improve estimates of species distributions and diversity patterns by capturing both vernal and late season species. Early season sampling may be particularly important for monitoring non-native plants in the Wallowa Mountains as most non-natives were concentrated in low elevation semiarid bunchgrass communities where spring and early summer specialization is common. Close

• 8. [Article] Responses of Pacific Northwest prairies to soil nutrient manipulations : implications for restoration of Castilleja levisecta and control of invasive species

  Pacific Northwest prairies have become significantly reduced in extent, and in the Willamette Valley of Oregon, less than one percent of native upland prairies remain. Many species have been impacted by ...

  Citation × Citation Citation Abstract Copy Title: Responses of Pacific Northwest prairies to soil nutrient manipulations : implications for restoration of Castilleja levisecta and control of invasive species Author: Lawrence, Caitlin Elizabeth Pacific Northwest prairies have become significantly reduced in extent, and in the Willamette Valley of Oregon, less than one percent of native upland prairies remain. Many species have been impacted by this extreme loss of habitat, including Castilleja levisecta (golden paintbrush), a threatened hemiparasitic forb species endemic to the Pacific Northwest. Many of the prairie fragments that remain are poor quality, and face the threat of invasion from non-native species and a loss of biodiversity. These non-native species pose an obstacle to restoration and to the reintroduction of threatened and endangered species. Nutrient enrichment has been shown to promote increased invasion of communities, decrease success of native species, and decrease biodiversity. A way to counter these effects is through carbon addition to the soil which stimulates microbial activity and immobilizes nutrients, making them unavailable to plants. This strategy has potential as a restoration tool to improve conditions for native species, which are often outcompeted under high nutrient conditions. We tested the efficacy of carbon addition for controlling non-native species and restoring C. levisecta in two Willamette Valley prairies. We created treatments of varying nutrient availability and measured the responses of the plant community and of C. levisecta. Experimental plots were established in autumn 2012 with either carbon (sucrose) addition, ambient soil nutrients (controls), or nutrient addition (NPK fertilizer). Nutrient treatments were reapplied throughout the length of the experiment. Crossed with these treatments in a fully factorial design were seeding treatments of C. levisecta and of thirteen other native species, to increase the diversity of the plant community, providing host plants for C. levisecta, a hemiparasitic plant. In the two growing seasons following treatment we conducted plant community surveys and counted and measured seedlings of C. levisecta to determine the effects of the nutrient manipulations and seeding treatments on the community overall and on this threatened plant. Community composition differed significantly between the different nutrient treatments (perMANOVA, p<0.001) at both study sites, and in both years of the experiment. Mean total vascular plant cover was significantly reduced by carbon addition compared to ambient nutrient availability, and increased by nutrient addition. Native grasses were unaffected by nutrient manipulation at either site, whereas non-native grasses were greatly reduced by carbon addition and increased by nutrient addition, compared to ambient soil nutrient availability. Non-native forbs were also greatly reduced by carbon addition, and were also reduced by nutrient addition by the second year of the experiment. Richness of non-native species was more affected by nutrient manipulation than richness of natives, and was either increased or unaffected by nutrient enrichment and decreased by carbon addition. Some non-native species were found to be highly affected by the nutrient manipulation, while others were not, suggesting that carbon addition may be an effective control for only certain non-native species. At both sites, C. levisecta emergence was lower in carbon addition plots compared with controls. In nutrient addition plots, C. levisecta emergence was higher at one site but lower at the other compared with controls, suggesting that nutrient addition may be beneficial only under certain conditions. Additionally, by the second year of the experiment, there was no difference in C. levisecta numbers between the control and nutrient addition plots at one site, and there were fewer in the nutrient addition plots than in controls at the other site. The seeding of additional native species increased community richness but had little effect on diversity and no effect on C. levisecta establishment. Overall, these results suggest that nutrient enrichment can promote the success of non-native species and that carbon addition can be used to counter these effects on a species- and site-specific basis. However, carbon addition did not improve reintroduction success of a threatened plant species, C. levisecta, and the effects of nutrient addition on its success after two years were mixed. Title: Responses of Pacific Northwest prairies to soil nutrient manipulations : implications for restoration of Castilleja levisecta and control of invasive species Author: Lawrence, Caitlin Elizabeth Pacific Northwest prairies have become significantly reduced in extent, and in the Willamette Valley of Oregon, less than one percent of native upland prairies remain. Many species have been impacted by this extreme loss of habitat, including Castilleja levisecta (golden paintbrush), a threatened hemiparasitic forb species endemic to the Pacific Northwest. Many of the prairie fragments that remain are poor quality, and face the threat of invasion from non-native species and a loss of biodiversity. These non-native species pose an obstacle to restoration and to the reintroduction of threatened and endangered species. Nutrient enrichment has been shown to promote increased invasion of communities, decrease success of native species, and decrease biodiversity. A way to counter these effects is through carbon addition to the soil which stimulates microbial activity and immobilizes nutrients, making them unavailable to plants. This strategy has potential as a restoration tool to improve conditions for native species, which are often outcompeted under high nutrient conditions. We tested the efficacy of carbon addition for controlling non-native species and restoring C. levisecta in two Willamette Valley prairies. We created treatments of varying nutrient availability and measured the responses of the plant community and of C. levisecta. Experimental plots were established in autumn 2012 with either carbon (sucrose) addition, ambient soil nutrients (controls), or nutrient addition (NPK fertilizer). Nutrient treatments were reapplied throughout the length of the experiment. Crossed with these treatments in a fully factorial design were seeding treatments of C. levisecta and of thirteen other native species, to increase the diversity of the plant community, providing host plants for C. levisecta, a hemiparasitic plant. In the two growing seasons following treatment we conducted plant community surveys and counted and measured seedlings of C. levisecta to determine the effects of the nutrient manipulations and seeding treatments on the community overall and on this threatened plant. Community composition differed significantly between the different nutrient treatments (perMANOVA, p<0.001) at both study sites, and in both years of the experiment. Mean total vascular plant cover was significantly reduced by carbon addition compared to ambient nutrient availability, and increased by nutrient addition. Native grasses were unaffected by nutrient manipulation at either site, whereas non-native grasses were greatly reduced by carbon addition and increased by nutrient addition, compared to ambient soil nutrient availability. Non-native forbs were also greatly reduced by carbon addition, and were also reduced by nutrient addition by the second year of the experiment. Richness of non-native species was more affected by nutrient manipulation than richness of natives, and was either increased or unaffected by nutrient enrichment and decreased by carbon addition. Some non-native species were found to be highly affected by the nutrient manipulation, while others were not, suggesting that carbon addition may be an effective control for only certain non-native species. At both sites, C. levisecta emergence was lower in carbon addition plots compared with controls. In nutrient addition plots, C. levisecta emergence was higher at one site but lower at the other compared with controls, suggesting that nutrient addition may be beneficial only under certain conditions. Additionally, by the second year of the experiment, there was no difference in C. levisecta numbers between the control and nutrient addition plots at one site, and there were fewer in the nutrient addition plots than in controls at the other site. The seeding of additional native species increased community richness but had little effect on diversity and no effect on C. levisecta establishment. Overall, these results suggest that nutrient enrichment can promote the success of non-native species and that carbon addition can be used to counter these effects on a species- and site-specific basis. However, carbon addition did not improve reintroduction success of a threatened plant species, C. levisecta, and the effects of nutrient addition on its success after two years were mixed. Close

• 9. [Article] Non-Native Plant Invasion along Elevation and Canopy Closure Gradients in a Middle Rocky Mountain Ecosystem

  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 article was published by the Public Library ...

  Citation × Citation Citation Abstract Copy Title: Non-Native Plant Invasion along Elevation and Canopy Closure Gradients in a Middle Rocky Mountain Ecosystem Author: Parks, Catherine G., DelCurto, Tim, Mata-González, Ricardo, Naylor, Bridgett J., McCune, Bruce, Averett, Joshua P. 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 article was published by the Public Library of Science and is in the public domain. The published article can be found at: http://www.plosone.org/ Title: Non-Native Plant Invasion along Elevation and Canopy Closure Gradients in a Middle Rocky Mountain Ecosystem Author: Parks, Catherine G., DelCurto, Tim, Mata-González, Ricardo, Naylor, Bridgett J., McCune, Bruce, Averett, Joshua P. 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 article was published by the Public Library of Science and is in the public domain. The published article can be found at: http://www.plosone.org/ Close

• 10. [Article] Final Report 1994-1997: Effects of Fire, Mowing, and Mowing with Herbicide on Native Prairie of Baskett Butte, Baskett Slough NWR

  We report results from a field experiment evaluating the effectiveness of mowing, mowing and herbicides, and burning on woody plants, key native and non-native grasses and forbs, and the Fender’s blue ...

  Citation × Citation Citation Abstract Copy Title: Final Report 1994-1997: Effects of Fire, Mowing, and Mowing with Herbicide on Native Prairie of Baskett Butte, Baskett Slough NWR Author: Wilson, Mark V., Clark, Deborah Louise, 1950- We report results from a field experiment evaluating the effectiveness of mowing, mowing and herbicides, and burning on woody plants, key native and non-native grasses and forbs, and the Fender’s blue butterfly. The goal was to find a technique that controlled woody pest plants without harming native species or promoting non-native species. Three years after the initial manipulations, all treatments significantly reduced woody plant cover. Mowing promoted the group of measured native grasses without promoting non-native species. In contrast, burning had mixed effects on herbaceous species, promoting growth for some species and decreasing growth for others. Each treatment, particularly mowing, caused local increases in numbers of Fender’s blue butterfly egg masses, probably because lupines invigorated by treatments attracted ovipositing females. Although prescribed burning seemed to kill larvae, treated areas still accumulated more eggs masses than in controls. Three years after the start of manipulations, mowing was the most effective overall treatment for controlling woody plants, increasing native species abundance without promoting non-native species, and increasing Fender’s blue butterfly numbers. We recommend mowing for restoring similar habitats. Prescribed burning would also be an effective choice for habitat restoration. Title: Final Report 1994-1997: Effects of Fire, Mowing, and Mowing with Herbicide on Native Prairie of Baskett Butte, Baskett Slough NWR Author: Wilson, Mark V., Clark, Deborah Louise, 1950- We report results from a field experiment evaluating the effectiveness of mowing, mowing and herbicides, and burning on woody plants, key native and non-native grasses and forbs, and the Fender’s blue butterfly. The goal was to find a technique that controlled woody pest plants without harming native species or promoting non-native species. Three years after the initial manipulations, all treatments significantly reduced woody plant cover. Mowing promoted the group of measured native grasses without promoting non-native species. In contrast, burning had mixed effects on herbaceous species, promoting growth for some species and decreasing growth for others. Each treatment, particularly mowing, caused local increases in numbers of Fender’s blue butterfly egg masses, probably because lupines invigorated by treatments attracted ovipositing females. Although prescribed burning seemed to kill larvae, treated areas still accumulated more eggs masses than in controls. Three years after the start of manipulations, mowing was the most effective overall treatment for controlling woody plants, increasing native species abundance without promoting non-native species, and increasing Fender’s blue butterfly numbers. We recommend mowing for restoring similar habitats. Prescribed burning would also be an effective choice for habitat restoration. Close