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• 11. [Article] Patterns in responses of an amphibian assemblage to wetland restoration

  Wetland restoration success in attaining wildlife conservation goals can be confounded by the presence of multiple biological invaders. Wetland management activities typically target invasive plants, ...

  Citation × Citation Citation Abstract Copy Title: Patterns in responses of an amphibian assemblage to wetland restoration Author: Rowe, Jennifer C. Wetland restoration success in attaining wildlife conservation goals can be confounded by the presence of multiple biological invaders. Wetland management activities typically target invasive plants, but bottom-up responses of higher trophic levels in novel communities are difficult to predict. We surveyed plant and amphibian assemblages at 26 sites enrolled in the Wetlands Reserve Program (WRP) in the Willamette Valley, Oregon to determine the relative importance of plant management, non-native species presence, and surrounding landscape for amphibians across multiple life history stages. Explanatory variables negatively associated with native anuran counts included percent invasive plant cover, invasive bullfrog counts, non-native fish presence, and area of urban land cover. In addition, native anurans were positively associated with WRP site age, suggesting that the benefits of restored wetlands may increase over time. Although invasive plant management provided indirect benefits to native amphibians, the most effective way to enhance native amphibian populations may be through eliminating the strong top-down forces exerted by non-native vertebrates. We also explored the impact of restoration activities on predator/prey dynamics by analyzing bullfrog diet contents. We sampled vegetation and analyzed bullfrog diet contents from 10 WRP wetlands categorized by management intensity and hydrology to determine whether prey consumption patterns (abundance, richness, and % large prey), diet breadth, and dietary community (based on taxonomic and prey size composition) differed among wetlands categorized by management regime and hydroperiod. We found disparities in the diet breadth with respect to wetland categories, with bullfrogs consuming a disproportionate abundance of few prey orders at actively managed sites. Diet breadth could have been influenced by frequent applications of restoration treatments, as invertebrate species richness and abundance is often negatively linked to habitat disturbance. Dietary taxonomic composition also differed between wetland groups, but prey size composition did not. Instead, prey size was strongly influenced by site-level vegetation covariates; large-bodied prey consumption was positively associated with plant species richness. However, diet dry mass was highest in wetlands with high invasive plant cover, suggesting that other factors, such as foraging activity rates, should be considered to fully understand how bullfrogs meet energy demands in managed wetlands. Variation in native and invasive amphibian responses to wetland restoration efforts may provide important information on how habitat structure and composition influence trophic dynamics. Given that the outcomes of plant control on wildlife may not follow planned trajectories in invasive-dominated systems, this research addresses the need for a community approach to assessments of restoration success. Title: Patterns in responses of an amphibian assemblage to wetland restoration Author: Rowe, Jennifer C. Wetland restoration success in attaining wildlife conservation goals can be confounded by the presence of multiple biological invaders. Wetland management activities typically target invasive plants, but bottom-up responses of higher trophic levels in novel communities are difficult to predict. We surveyed plant and amphibian assemblages at 26 sites enrolled in the Wetlands Reserve Program (WRP) in the Willamette Valley, Oregon to determine the relative importance of plant management, non-native species presence, and surrounding landscape for amphibians across multiple life history stages. Explanatory variables negatively associated with native anuran counts included percent invasive plant cover, invasive bullfrog counts, non-native fish presence, and area of urban land cover. In addition, native anurans were positively associated with WRP site age, suggesting that the benefits of restored wetlands may increase over time. Although invasive plant management provided indirect benefits to native amphibians, the most effective way to enhance native amphibian populations may be through eliminating the strong top-down forces exerted by non-native vertebrates. We also explored the impact of restoration activities on predator/prey dynamics by analyzing bullfrog diet contents. We sampled vegetation and analyzed bullfrog diet contents from 10 WRP wetlands categorized by management intensity and hydrology to determine whether prey consumption patterns (abundance, richness, and % large prey), diet breadth, and dietary community (based on taxonomic and prey size composition) differed among wetlands categorized by management regime and hydroperiod. We found disparities in the diet breadth with respect to wetland categories, with bullfrogs consuming a disproportionate abundance of few prey orders at actively managed sites. Diet breadth could have been influenced by frequent applications of restoration treatments, as invertebrate species richness and abundance is often negatively linked to habitat disturbance. Dietary taxonomic composition also differed between wetland groups, but prey size composition did not. Instead, prey size was strongly influenced by site-level vegetation covariates; large-bodied prey consumption was positively associated with plant species richness. However, diet dry mass was highest in wetlands with high invasive plant cover, suggesting that other factors, such as foraging activity rates, should be considered to fully understand how bullfrogs meet energy demands in managed wetlands. Variation in native and invasive amphibian responses to wetland restoration efforts may provide important information on how habitat structure and composition influence trophic dynamics. Given that the outcomes of plant control on wildlife may not follow planned trajectories in invasive-dominated systems, this research addresses the need for a community approach to assessments of restoration success. Close

• 12. [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. 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• 13. [Article] Integrating functional trait frameworks into restoration : the role of seed and seedling traits in recruitment success

  Seeding is a vital tool to facilitate recovery of degraded ecosystems, but low seedling recruitment rates limit the utility of this practice in a range of ecosystems across the globe. Plant functional ...

  Citation × Citation Citation Abstract Copy Title: Integrating functional trait frameworks into restoration : the role of seed and seedling traits in recruitment success Author: Larson, Julie E. Seeding is a vital tool to facilitate recovery of degraded ecosystems, but low seedling recruitment rates limit the utility of this practice in a range of ecosystems across the globe. Plant functional traits impact individual fitness through effects on growth, reproduction and survival. Consequently, seed and seedling trait variation among species provide a critical mechanism to understand and explain variation in recruitment probabilities across restoration species. I measured seed traits, seedling traits, and field probabilities of germination, emergence, seedling establishment, and established seedling survival for 47 varieties of native and introduced grasses in U.S. western drylands. Multivariate analyses were used to identify major dimensions of trait variation across early life stages and to assess whether this trait variation was related to cumulative survival probabilities through the first growing season. Ordination and cluster analysis of seed and seedling traits highlighted two central, independent aspects of functional trait variation among grasses describing seedling growth rate and germination rate, but functional trait-based clusters failed to capture variation in recruitment patterns in the field. Path analysis revealed that variation in germination and emergence probabilities explained over 90% of the variation in cumulative survival in the first growing season. However, functional traits including seed mass, hydrothermal time, and coleoptile tissue density, explained just 16% and 18% of the variation in germination and emergence, respectively, under ambient conditions. The majority of functional trait work has centered on linking leaf and root traits to resource acquisition, utilization, and growth. Our study suggests that germination, emergence and functional traits associated with these processes are leading drivers of recruitment variation across species in restoration scenarios. Functional traits reflecting the physiology and morphology of germinated seedlings, such as coleoptile tissue density, may play a major role in differentiating recruitment success following seeding, but remain largely unexplored. Before functional traits can facilitate practical advances in seeding and restoration efforts, we must improve our understanding of the dimensions and consequences of trait variation during germination and emergence. Title: Integrating functional trait frameworks into restoration : the role of seed and seedling traits in recruitment success Author: Larson, Julie E. Seeding is a vital tool to facilitate recovery of degraded ecosystems, but low seedling recruitment rates limit the utility of this practice in a range of ecosystems across the globe. Plant functional traits impact individual fitness through effects on growth, reproduction and survival. Consequently, seed and seedling trait variation among species provide a critical mechanism to understand and explain variation in recruitment probabilities across restoration species. I measured seed traits, seedling traits, and field probabilities of germination, emergence, seedling establishment, and established seedling survival for 47 varieties of native and introduced grasses in U.S. western drylands. Multivariate analyses were used to identify major dimensions of trait variation across early life stages and to assess whether this trait variation was related to cumulative survival probabilities through the first growing season. Ordination and cluster analysis of seed and seedling traits highlighted two central, independent aspects of functional trait variation among grasses describing seedling growth rate and germination rate, but functional trait-based clusters failed to capture variation in recruitment patterns in the field. Path analysis revealed that variation in germination and emergence probabilities explained over 90% of the variation in cumulative survival in the first growing season. However, functional traits including seed mass, hydrothermal time, and coleoptile tissue density, explained just 16% and 18% of the variation in germination and emergence, respectively, under ambient conditions. The majority of functional trait work has centered on linking leaf and root traits to resource acquisition, utilization, and growth. Our study suggests that germination, emergence and functional traits associated with these processes are leading drivers of recruitment variation across species in restoration scenarios. Functional traits reflecting the physiology and morphology of germinated seedlings, such as coleoptile tissue density, may play a major role in differentiating recruitment success following seeding, but remain largely unexplored. Before functional traits can facilitate practical advances in seeding and restoration efforts, we must improve our understanding of the dimensions and consequences of trait variation during germination and emergence. Close

• 14. [Article] Plant community dynamics in remnant and restored Willamette Valley wetland prairies

  Invasion by exotic species can pose a major challenge for developing native plant communities in wetland restoration projects. Often native plant communities do not develop as anticipated in restored wetlands ...

  Citation × Citation Citation Abstract Copy Title: Plant community dynamics in remnant and restored Willamette Valley wetland prairies Author: Schwindt, Rachel A. Invasion by exotic species can pose a major challenge for developing native plant communities in wetland restoration projects. Often native plant communities do not develop as anticipated in restored wetlands due to colonization by exotic species that dominate the native plant community. Despite the time and expense to restore wetlands, there has been little long term research to compare plant communities in restored and natural wetland sites. Research into plant community diversity across several wetland sites over several years can provide a broader perspective into how these ecosystems recover from long-term disturbance. The objective of this study was to compare plant community change from 2000 to 2005 between restored and remnant wetland prairie sites in the southern Willamette Valley in Oregon to determine if exotic species abundance was consistent between these groups. Specific objectives included 1) comparing the diversity and abundance of all species in remnant and restored wetland prairie sites, 2) evaluate the trajectory of community change between remnant and restored wetland prairie sites to determine if there was rapid change in restored sites, and 3) describe the plot level heterogeneity of the plant community in all sites to determine how microsites influence diversity. In 2005, species abundance was re-measured in four remnant wetland prairies and four restored wetland prairies that had been selected for an unrelated vegetation survey in 2000. Species were characterized by life form, origin, and wetland indicator status. Species abundance between groups of remnant and restored sites were compared using a multi-response permutation procedure (MRPP). The plant community trajectory was evaluated with nonmetric multidimensional scaling (NMS) and tested for significance with multivariate analysis of variance (MANOVA). Species area curves were compared between sites and within remnant and restored groups of plots. Within-year and between-year significance tests indicated that remnant and restored sites were similar in exotic species abundance, graminoid abundance, and wetland species abundance with no significant difference between these remnant and restored wetland prairie sites. Individual sites in both groups experienced changes in exotic species abundance which confounded the statistical results. Species heterogeneity was no more spatially diverse across the remnant site plots than restored site plots. Species area curves did not show significant differences between remnant and restored plots but individual plots did show homogeneous community characteristics at smaller spatial scales. Restoration sites had developed high graminoid cover by the 2000 survey which was conducted two to three years after restoration was initiated. All sites were equally likely to contain exotic species. Exotic species common across all sites included Centaurium umbellatum, Holcus lanatus, and Hypericum perforatum. Native species common across sites included Deschampsia cespitosa, Danthonia californica and Juncus tenuis. These results suggested that differences between remnant and restored Willamette Valley wetland prairie sites were not generalizable at the landscape scale and were more dependent on site specific management activities and local barriers to colonization. Five years may not be enough time to see evidence that suggests if restored plant communities will develop spatial characteristics of the remnant sites. This research does suggest that multi-site comparisons help distinguish individual sites that are not developing characteristics of remnant wetland plant communities. Title: Plant community dynamics in remnant and restored Willamette Valley wetland prairies Author: Schwindt, Rachel A. Invasion by exotic species can pose a major challenge for developing native plant communities in wetland restoration projects. Often native plant communities do not develop as anticipated in restored wetlands due to colonization by exotic species that dominate the native plant community. Despite the time and expense to restore wetlands, there has been little long term research to compare plant communities in restored and natural wetland sites. Research into plant community diversity across several wetland sites over several years can provide a broader perspective into how these ecosystems recover from long-term disturbance. The objective of this study was to compare plant community change from 2000 to 2005 between restored and remnant wetland prairie sites in the southern Willamette Valley in Oregon to determine if exotic species abundance was consistent between these groups. Specific objectives included 1) comparing the diversity and abundance of all species in remnant and restored wetland prairie sites, 2) evaluate the trajectory of community change between remnant and restored wetland prairie sites to determine if there was rapid change in restored sites, and 3) describe the plot level heterogeneity of the plant community in all sites to determine how microsites influence diversity. In 2005, species abundance was re-measured in four remnant wetland prairies and four restored wetland prairies that had been selected for an unrelated vegetation survey in 2000. Species were characterized by life form, origin, and wetland indicator status. Species abundance between groups of remnant and restored sites were compared using a multi-response permutation procedure (MRPP). The plant community trajectory was evaluated with nonmetric multidimensional scaling (NMS) and tested for significance with multivariate analysis of variance (MANOVA). Species area curves were compared between sites and within remnant and restored groups of plots. Within-year and between-year significance tests indicated that remnant and restored sites were similar in exotic species abundance, graminoid abundance, and wetland species abundance with no significant difference between these remnant and restored wetland prairie sites. Individual sites in both groups experienced changes in exotic species abundance which confounded the statistical results. Species heterogeneity was no more spatially diverse across the remnant site plots than restored site plots. Species area curves did not show significant differences between remnant and restored plots but individual plots did show homogeneous community characteristics at smaller spatial scales. Restoration sites had developed high graminoid cover by the 2000 survey which was conducted two to three years after restoration was initiated. All sites were equally likely to contain exotic species. Exotic species common across all sites included Centaurium umbellatum, Holcus lanatus, and Hypericum perforatum. Native species common across sites included Deschampsia cespitosa, Danthonia californica and Juncus tenuis. These results suggested that differences between remnant and restored Willamette Valley wetland prairie sites were not generalizable at the landscape scale and were more dependent on site specific management activities and local barriers to colonization. Five years may not be enough time to see evidence that suggests if restored plant communities will develop spatial characteristics of the remnant sites. This research does suggest that multi-site comparisons help distinguish individual sites that are not developing characteristics of remnant wetland plant communities. Close

• 15. [Article] Fire effects on wetland prairie species: final report

  Project No. 14-48-0001-96749

  Citation × Citation Citation Abstract Copy Title: Fire effects on wetland prairie species: final report Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Project No. 14-48-0001-96749 Title: Fire effects on wetland prairie species: final report Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Project No. 14-48-0001-96749 Close

• 16. [Article] Yield responses of invasive grasses to carbon doses

  The sagebrush steppe ecosystem of the northern Great Basin is severely degraded and continues to decline due in large part to the invasive, non-native annual grasses Bromus tectorum L. (cheatgrass) and ...

  Citation × Citation Citation Abstract Copy Title: Yield responses of invasive grasses to carbon doses Author: Brunson, Jessi L. The sagebrush steppe ecosystem of the northern Great Basin is severely degraded and continues to decline due in large part to the invasive, non-native annual grasses Bromus tectorum L. (cheatgrass) and Taeniatherum caput-medusae (L.) Nevski (medusahead). Restoration of invasive-dominated areas is difficult, but can be enhanced by adding a carbon source, which stimulates microbes to immobilize soil inorganic N and reduces yields of fast-growing ruderal plants. How much carbon is needed to induce this effect is uncertain, so our research objectives were to establish a response to increasing carbon doses and calculate the lowest dose where a significant response was observed for 1) biomass, density, and seed production of cheatgrass and medusahead; 2) soil microbial biomass C and N; and 3) inorganic soil N. In November 2005 we applied 12 carbon doses ranging from 0 to 2400 kg C/ha as sucrose to plots planted with cheatgrass and medusahead at two sites in the northern Great Basin. We measured aboveground plant biomass when plants matured in June and July 2006 and microbial biomass in November 2005, March 2006, and July 2006. Inorganic soil N was measured using mixed-bed resin capsules placed in situ for the duration of the study. For an increase in carbon dose of 100 kg C/ha, back-transformed mean medusahead biomass (g/m²) at one site decreased 6.8%. This was the only significant response to carbon doses for both target species across both sites. In addition to cheatgrass and medusahead, other ruderal plants established in our plots, and the biomass of this entire ruderal community decreased approximately 6% for an increase in carbon dose of 100 kg C/ha at both sites. Microbial biomass C increased 2-4 mg/kg for an increase in carbon of 100 kg C/ha at the two earliest sampling dates at both sites, while microbial biomass N increased at only one site at the earliest sampling date, and this increase was 0.3 mg/kg for an increase in carbon of 100 kg C/ha. Soil NO3₃⁻-N decreased at both sites with increasing carbon. For a significant reduction in ruderal biomass, we calculated lowest significant doses of 240-640 kg C/ha, but it remains to be determined if this reduction is sufficient to facilitate establishment of native perennials in northern Great Basin restoration projects. Title: Yield responses of invasive grasses to carbon doses Author: Brunson, Jessi L. The sagebrush steppe ecosystem of the northern Great Basin is severely degraded and continues to decline due in large part to the invasive, non-native annual grasses Bromus tectorum L. (cheatgrass) and Taeniatherum caput-medusae (L.) Nevski (medusahead). Restoration of invasive-dominated areas is difficult, but can be enhanced by adding a carbon source, which stimulates microbes to immobilize soil inorganic N and reduces yields of fast-growing ruderal plants. How much carbon is needed to induce this effect is uncertain, so our research objectives were to establish a response to increasing carbon doses and calculate the lowest dose where a significant response was observed for 1) biomass, density, and seed production of cheatgrass and medusahead; 2) soil microbial biomass C and N; and 3) inorganic soil N. In November 2005 we applied 12 carbon doses ranging from 0 to 2400 kg C/ha as sucrose to plots planted with cheatgrass and medusahead at two sites in the northern Great Basin. We measured aboveground plant biomass when plants matured in June and July 2006 and microbial biomass in November 2005, March 2006, and July 2006. Inorganic soil N was measured using mixed-bed resin capsules placed in situ for the duration of the study. For an increase in carbon dose of 100 kg C/ha, back-transformed mean medusahead biomass (g/m²) at one site decreased 6.8%. This was the only significant response to carbon doses for both target species across both sites. In addition to cheatgrass and medusahead, other ruderal plants established in our plots, and the biomass of this entire ruderal community decreased approximately 6% for an increase in carbon dose of 100 kg C/ha at both sites. Microbial biomass C increased 2-4 mg/kg for an increase in carbon of 100 kg C/ha at the two earliest sampling dates at both sites, while microbial biomass N increased at only one site at the earliest sampling date, and this increase was 0.3 mg/kg for an increase in carbon of 100 kg C/ha. Soil NO3₃⁻-N decreased at both sites with increasing carbon. For a significant reduction in ruderal biomass, we calculated lowest significant doses of 240-640 kg C/ha, but it remains to be determined if this reduction is sufficient to facilitate establishment of native perennials in northern Great Basin restoration projects. Close

• 17. [Article] Mowing Wyoming Big Sagebrush Communities With Degraded Herbaceous Understories: Has a Threshold Been Crossed?

  This is the publisher’s final pdf. The published article is copyrighted by the Society for Range Management and can be found at: http://www.srmjournals.org/loi/rama. To the best of our knowledge, one or ...

  Citation × Citation Citation Abstract Copy Title: Mowing Wyoming Big Sagebrush Communities With Degraded Herbaceous Understories: Has a Threshold Been Crossed? Author: Nafus, Aleta M., Bates, Jonathan D., Davies, Kirk W. This is the publisher’s final pdf. The published article is copyrighted by the Society for Range Management and can be found at: http://www.srmjournals.org/loi/rama. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Mowing Wyoming Big Sagebrush Communities With Degraded Herbaceous Understories: Has a Threshold Been Crossed? Author: Nafus, Aleta M., Bates, Jonathan D., Davies, Kirk W. This is the publisher’s final pdf. The published article is copyrighted by the Society for Range Management and can be found at: http://www.srmjournals.org/loi/rama. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 18. [Article] Evaluating Coastal Protection Services Associated with Restoration Management of an Endangered Shorebird in Oregon, U.S.A.

  Coastal sand dunes and beaches offer a variety of ecosystem services such as coastal protection, sand stabilization, species conservation, and recreation. However, the management and balance of ecosystem ...

  Citation × Citation Citation Abstract Copy Title: Evaluating Coastal Protection Services Associated with Restoration Management of an Endangered Shorebird in Oregon, U.S.A. Author: Carroll, Lindsay J. Coastal sand dunes and beaches offer a variety of ecosystem services such as coastal protection, sand stabilization, species conservation, and recreation. However, the management and balance of ecosystem services offered by dunes and beaches is challenging when ecosystem services interact across the landscape. Management focusing only on one ecosystem service may result in unintended consequences and trade-offs between other key services. Understanding the magnitude of the trade-offs and linkages between services provides a more holistic approach for reducing unintended consequences and maximizing function. The degradation of habitats and land use changes associated with expanding human populations has resulted in the need for species conservation. However, species conservation techniques can sometimes have unintended consequences for other services. Given the mandate of the Endangered Species Act to restore habitat structure and function essential to endangered or threatened species, it becomes critical to evaluate the implications of species conservation management initiatives to reduce negative implications to other key services. The coastal dune systems of the Pacific Northwest (PNW) are a prime example of how ecosystem services, such as species conservation and coastal protection, can interact with one another. Over the last 125 years in the Pacific Northwest (PNW), the intentional introduction of two non-native congeneric beach grasses (Ammophila arenaria and A. breviligulata) has increased coastal protection through the creation of foredunes, but also dramatically altered the dune ecosystem. Both invasive grasses build taller dunes that range from 3 - 18 m in height compared to the native grass, Elymus mollis. Increased foredune elevations generate greater coastal protection services that are increasingly important given sea level rise and extreme storm events on the PNW coast. However, the beach grasses have dramatically changed the beach/dune community, resulting in the decline of several native dune plants and animals. One species that is negatively affected by the grass invasion is the Western snowy plover (Charadrius nivosus nivosus), an endemic shorebird living on beaches and dunes in the Pacific Northwest. This shorebird was listed threatened under the Endangered Species Act in 1993 and a recovery plan was established that employed multiple recovery techniques. The most important part of the plan involves establishing habitat restoration areas (HRAs) where dunes are bulldozed, reducing dune elevations, burying the grass, and returning the dunes to an open shifting sand environment, historically preferred by the plover. Recent coastal hazards modeling revealed that the changes in beach and dune shape associated with plover restoration increases coastal exposure to flooding and erosion at certain locations along the Oregon coast, particularly under projected climate change scenarios of sea level rise and extreme storms. As part of future plover management, four critical habitat areas were proposed for Tillamook County, Oregon: Nehalem River Spit, Bayocean Spit, Netarts Spit, and Sand Lake South. Given the interest in plover habitat restoration in Tillamook County, this research project addresses the following questions: (1) What is the present day dune geomorphology and exposure to coastal hazards at four proposed critical habitat (PCH) areas in Tillamook County, Oregon; and (2) how do changes in beach geomorphology associated with different restoration scenarios alter coastal exposure today, under projected sea level rise and storm scenarios? To address the coastal geomorphological impacts of HRA installation on the four proposed areas, multiple restoration scenarios that reduce foredune elevation were evaluated under present day sea level and potential future sea level rise and extreme storminess scenarios, using coastal exposure modeling techniques. The model projections provide site-specific information on the exposure of HRAs to overtopping under different restoration conditions. We determined that exposure to flooding was dependent on proposed HRA site and restoration scenario, and was exacerbated by sea level rise and extreme storms. Empirical models projected the greatest flooding exposure would occur at Nehalem River Spit, followed by Netarts Spit, and then Bayocean Spit and Sand Lake South, which did not differ. Exposure to flooding at present day dunes was low across all sites, but with increasing exposure to flooding as foredune elevations were reduced to 6.0 m or below, as could happen with plover habitat restoration. Under present day water levels, restoring foredune elevations to 6.0 m or below would likely result in roughly 5 days of overtopping per year at Nehalem River Spit, Bayocean Spit, and Netarts Spit, and 4 days of overtopping at Sand Lake South. Flooding under various foredune restoration scenarios increased under higher sea level rise scenarios. Flooding exposure for the 6.0 m restoration scenario exceeded 10 days per year at Nehalem River Spit and 5 days per year at Bayocean Spit, Netarts Spit, and Sand Lake South. Overall exposure to flooding under the extreme storm scenarios was dependent on proposed HRA site, restoration scenario, and increased wave conditions, such as wave height, period, and water level. Similar to the empirical model, flooding exposure under extreme storm scenarios increased when foredune elevations were reduced to 6.0 m or below, across all sites. The site with the greatest overall flooding exposure during extreme storms was Bayocean Spit. Flooding distance was dependent on restoration scenario and site while flooding duration was only dependent on restoration scenario. The 5.5 m restoration scenario under higher storm water levels resulted in one hour or more of flooding exposure at least one day per year at Nehalem River Spit, Netarts Spit, and Bayocean Spit. The overall likelihood of overwash extending to 150 m or more into the dune field during extreme storms was at least 5 days when selecting to reduce foredune to restoration elevations of 7.0 m or below across all sites. The effect of higher wave heights and greater wave periods was more important to overtopping distance than restoration scenario. Learning from current plover management, combined with the coastal exposure analysis we conducted here, could enable managers to develop site-specific restoration plans that maximize plover recovery while minimizing coastal exposure. This research will give resource managers information on the coastal exposure associated with proposed HRAs and the foredune reduction scenarios they might want to employ at the different sites. It will allow them to identify the best restoration scenarios to maximum habitat restoration without compromising coastal protection, and thus balance some important services of dunes and beaches. Regardless of management objective, identifying the unintended consequences of restoration to key ecosystem services is necessary for the holistic management of our dynamic coasts, especially with projected sea level rise and the uncertainty of frequent and extreme storms. Title: Evaluating Coastal Protection Services Associated with Restoration Management of an Endangered Shorebird in Oregon, U.S.A. Author: Carroll, Lindsay J. Coastal sand dunes and beaches offer a variety of ecosystem services such as coastal protection, sand stabilization, species conservation, and recreation. However, the management and balance of ecosystem services offered by dunes and beaches is challenging when ecosystem services interact across the landscape. Management focusing only on one ecosystem service may result in unintended consequences and trade-offs between other key services. Understanding the magnitude of the trade-offs and linkages between services provides a more holistic approach for reducing unintended consequences and maximizing function. The degradation of habitats and land use changes associated with expanding human populations has resulted in the need for species conservation. However, species conservation techniques can sometimes have unintended consequences for other services. Given the mandate of the Endangered Species Act to restore habitat structure and function essential to endangered or threatened species, it becomes critical to evaluate the implications of species conservation management initiatives to reduce negative implications to other key services. The coastal dune systems of the Pacific Northwest (PNW) are a prime example of how ecosystem services, such as species conservation and coastal protection, can interact with one another. Over the last 125 years in the Pacific Northwest (PNW), the intentional introduction of two non-native congeneric beach grasses (Ammophila arenaria and A. breviligulata) has increased coastal protection through the creation of foredunes, but also dramatically altered the dune ecosystem. Both invasive grasses build taller dunes that range from 3 - 18 m in height compared to the native grass, Elymus mollis. Increased foredune elevations generate greater coastal protection services that are increasingly important given sea level rise and extreme storm events on the PNW coast. However, the beach grasses have dramatically changed the beach/dune community, resulting in the decline of several native dune plants and animals. One species that is negatively affected by the grass invasion is the Western snowy plover (Charadrius nivosus nivosus), an endemic shorebird living on beaches and dunes in the Pacific Northwest. This shorebird was listed threatened under the Endangered Species Act in 1993 and a recovery plan was established that employed multiple recovery techniques. The most important part of the plan involves establishing habitat restoration areas (HRAs) where dunes are bulldozed, reducing dune elevations, burying the grass, and returning the dunes to an open shifting sand environment, historically preferred by the plover. Recent coastal hazards modeling revealed that the changes in beach and dune shape associated with plover restoration increases coastal exposure to flooding and erosion at certain locations along the Oregon coast, particularly under projected climate change scenarios of sea level rise and extreme storms. As part of future plover management, four critical habitat areas were proposed for Tillamook County, Oregon: Nehalem River Spit, Bayocean Spit, Netarts Spit, and Sand Lake South. Given the interest in plover habitat restoration in Tillamook County, this research project addresses the following questions: (1) What is the present day dune geomorphology and exposure to coastal hazards at four proposed critical habitat (PCH) areas in Tillamook County, Oregon; and (2) how do changes in beach geomorphology associated with different restoration scenarios alter coastal exposure today, under projected sea level rise and storm scenarios? To address the coastal geomorphological impacts of HRA installation on the four proposed areas, multiple restoration scenarios that reduce foredune elevation were evaluated under present day sea level and potential future sea level rise and extreme storminess scenarios, using coastal exposure modeling techniques. The model projections provide site-specific information on the exposure of HRAs to overtopping under different restoration conditions. We determined that exposure to flooding was dependent on proposed HRA site and restoration scenario, and was exacerbated by sea level rise and extreme storms. Empirical models projected the greatest flooding exposure would occur at Nehalem River Spit, followed by Netarts Spit, and then Bayocean Spit and Sand Lake South, which did not differ. Exposure to flooding at present day dunes was low across all sites, but with increasing exposure to flooding as foredune elevations were reduced to 6.0 m or below, as could happen with plover habitat restoration. Under present day water levels, restoring foredune elevations to 6.0 m or below would likely result in roughly 5 days of overtopping per year at Nehalem River Spit, Bayocean Spit, and Netarts Spit, and 4 days of overtopping at Sand Lake South. Flooding under various foredune restoration scenarios increased under higher sea level rise scenarios. Flooding exposure for the 6.0 m restoration scenario exceeded 10 days per year at Nehalem River Spit and 5 days per year at Bayocean Spit, Netarts Spit, and Sand Lake South. Overall exposure to flooding under the extreme storm scenarios was dependent on proposed HRA site, restoration scenario, and increased wave conditions, such as wave height, period, and water level. Similar to the empirical model, flooding exposure under extreme storm scenarios increased when foredune elevations were reduced to 6.0 m or below, across all sites. The site with the greatest overall flooding exposure during extreme storms was Bayocean Spit. Flooding distance was dependent on restoration scenario and site while flooding duration was only dependent on restoration scenario. The 5.5 m restoration scenario under higher storm water levels resulted in one hour or more of flooding exposure at least one day per year at Nehalem River Spit, Netarts Spit, and Bayocean Spit. The overall likelihood of overwash extending to 150 m or more into the dune field during extreme storms was at least 5 days when selecting to reduce foredune to restoration elevations of 7.0 m or below across all sites. The effect of higher wave heights and greater wave periods was more important to overtopping distance than restoration scenario. Learning from current plover management, combined with the coastal exposure analysis we conducted here, could enable managers to develop site-specific restoration plans that maximize plover recovery while minimizing coastal exposure. This research will give resource managers information on the coastal exposure associated with proposed HRAs and the foredune reduction scenarios they might want to employ at the different sites. It will allow them to identify the best restoration scenarios to maximum habitat restoration without compromising coastal protection, and thus balance some important services of dunes and beaches. Regardless of management objective, identifying the unintended consequences of restoration to key ecosystem services is necessary for the holistic management of our dynamic coasts, especially with projected sea level rise and the uncertainty of frequent and extreme storms. Close