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• 1. [Article] The effects of land use on mineral flat wetland hydrologic processes in lowland agricultural catchments

  Hydrologic processes within mineral flat wetlands, along with their connections to groundwater and downstream surface water in lowland agricultural catchments are poorly understood, particularly under ...

  Citation × Citation Citation Abstract Copy Title: The effects of land use on mineral flat wetland hydrologic processes in lowland agricultural catchments Author: Marshall, Sarah M. (Sarah Marie) Hydrologic processes within mineral flat wetlands, along with their connections to groundwater and downstream surface water in lowland agricultural catchments are poorly understood, particularly under different land uses. In the three field studies included in this thesis, we examined infiltration, wetland hydroperiod, groundwater recharge dynamics, surface runoff generation, and water quality in mineral flat wetlands using a combination of soil and hydrometric measurements, stable isotope tracers, and water chemistry analysis. Our overarching objectives were to examine, for mineral flat wetlands under native prairie, farmed grassland, and restored prairie land cover: 1) how different land management influences infiltration and wetland hydroperiod at the plot scale, 2) the effects of land use on seasonal groundwater-surface water dynamics at the field scale, and 3) seasonal variation in runoff sources and nutrient transport from native prairie and farmed wetlands at the small catchment scale. At the plot scale, our results suggest that edaphic factors, particularly those related to soil structure, are strongly associated with wetland infiltration and overall hydroperiod across least-altered prairie, farmed, and restored prairie mineral flat wetlands. The hydroperiod metrics we examined were generally more sensitive to level of site disturbance than land use alone. At the field scale, our results indicate that, in spite of land use differences and slight variations in soil stratigraphy, many similarities exist in overall wetland hydroperiod, water sources and evaporation rates for mineral flat wetlands in the Willamette Valley lowlands. Isotopic evidence suggests that the greatest degree of groundwater-surface water mixing occurs in the upper 0.5 m of the saturated soil profile across sites under all land uses. Finally, at the small catchment scale, farmed wetland runoff was isotopically similar to field surface water for most of the wet season, indicating that saturation excess was an important runoff generation process. Prairie wetland runoff was isotopically similar to upstream water throughout the winter, and briefly similar to shallow groundwater and surface water within the wetland in mid-spring. Throughout the wet season, elevated nitrate, sulfate, and chloride concentrations were observed in groundwater and surface water at the farm site, and deeper groundwater at the prairie site. Upstream-downstream runoff chemistry remained similar throughout the wet season at the prairie site. Farm site runoff chemistry reflected the dominant water source within the farm field throughout the wet season. Our findings suggest that, while surface water pathways dominate runoff from wetland flats under farm land use, large wetland flat fields have a high potential to absorb, store, and process nutrients and agrochemicals from on-site and nearby off-site chemical inputs. Mineral flats that maintain wetland hydrology in spite of farm use represent a unique balance between agricultural production and preservation of some of the water storage and delay, and water quality-related ecosystem services once provided at a much larger scale in the Willamette Valley lowlands. We anticipate that results of this work will lead to better understanding of key site-scale edaphic and hydrologic factors to consider when prioritizing and managing sites for restoration, and how site disturbance under a variety of land uses may impact different hydrologic processes and components of the wetland hydroperiod. Additionally, our results provide a better understanding of how land use affects seasonal runoff generation processes in mineral flat wetlands, and the water quality implications of modifying groundwater and surface water connectivity between mineral flats and surrounding surface drainage networks. Title: The effects of land use on mineral flat wetland hydrologic processes in lowland agricultural catchments Author: Marshall, Sarah M. (Sarah Marie) Hydrologic processes within mineral flat wetlands, along with their connections to groundwater and downstream surface water in lowland agricultural catchments are poorly understood, particularly under different land uses. In the three field studies included in this thesis, we examined infiltration, wetland hydroperiod, groundwater recharge dynamics, surface runoff generation, and water quality in mineral flat wetlands using a combination of soil and hydrometric measurements, stable isotope tracers, and water chemistry analysis. Our overarching objectives were to examine, for mineral flat wetlands under native prairie, farmed grassland, and restored prairie land cover: 1) how different land management influences infiltration and wetland hydroperiod at the plot scale, 2) the effects of land use on seasonal groundwater-surface water dynamics at the field scale, and 3) seasonal variation in runoff sources and nutrient transport from native prairie and farmed wetlands at the small catchment scale. At the plot scale, our results suggest that edaphic factors, particularly those related to soil structure, are strongly associated with wetland infiltration and overall hydroperiod across least-altered prairie, farmed, and restored prairie mineral flat wetlands. The hydroperiod metrics we examined were generally more sensitive to level of site disturbance than land use alone. At the field scale, our results indicate that, in spite of land use differences and slight variations in soil stratigraphy, many similarities exist in overall wetland hydroperiod, water sources and evaporation rates for mineral flat wetlands in the Willamette Valley lowlands. Isotopic evidence suggests that the greatest degree of groundwater-surface water mixing occurs in the upper 0.5 m of the saturated soil profile across sites under all land uses. Finally, at the small catchment scale, farmed wetland runoff was isotopically similar to field surface water for most of the wet season, indicating that saturation excess was an important runoff generation process. Prairie wetland runoff was isotopically similar to upstream water throughout the winter, and briefly similar to shallow groundwater and surface water within the wetland in mid-spring. Throughout the wet season, elevated nitrate, sulfate, and chloride concentrations were observed in groundwater and surface water at the farm site, and deeper groundwater at the prairie site. Upstream-downstream runoff chemistry remained similar throughout the wet season at the prairie site. Farm site runoff chemistry reflected the dominant water source within the farm field throughout the wet season. Our findings suggest that, while surface water pathways dominate runoff from wetland flats under farm land use, large wetland flat fields have a high potential to absorb, store, and process nutrients and agrochemicals from on-site and nearby off-site chemical inputs. Mineral flats that maintain wetland hydrology in spite of farm use represent a unique balance between agricultural production and preservation of some of the water storage and delay, and water quality-related ecosystem services once provided at a much larger scale in the Willamette Valley lowlands. We anticipate that results of this work will lead to better understanding of key site-scale edaphic and hydrologic factors to consider when prioritizing and managing sites for restoration, and how site disturbance under a variety of land uses may impact different hydrologic processes and components of the wetland hydroperiod. Additionally, our results provide a better understanding of how land use affects seasonal runoff generation processes in mineral flat wetlands, and the water quality implications of modifying groundwater and surface water connectivity between mineral flats and surrounding surface drainage networks. Close

• 2. [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

• 3. [Article] Progress report II: Restoring prairies: A synthesis of studies on vegetation and invasive species in support of effective management (Year two)

  Willamette Valley wetland and upland prairies are some of the most endangered ecosystems in the United States, and provide habitat for many federally listed species. Because these are dynamic systems, ...

  Citation × Citation Citation Abstract Copy Title: Progress report II: Restoring prairies: A synthesis of studies on vegetation and invasive species in support of effective management (Year two) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Willamette Valley wetland and upland prairies are some of the most endangered ecosystems in the United States, and provide habitat for many federally listed species. Because these are dynamic systems, subject to ecological succession and invasion by aggressive non-native species, prairies require active management to maintain management goals. This is true of all Willamette Valley prairies, whether intact, degraded, or reestablished. Yet restoration and conservation efforts often lack experimental validation. Our overall objective for this project is to synthesize the scientific information now available relevant to the prairie restoration efforts of the West Eugene Wetlands project and, where there is sufficient support, develop concrete and defensible management recommendations Successful ecosystem restoration requires establishing and maintaining native plants. In turn, plant establishment hinges on having suitable environmental conditions, using species with adequate germination rates, and reducing competitive pressure from nonnative plants. In year one of this project, we synthesized the wealth of data in the West Eugene Wetlands establishment data set on plant abundance after sowing native species during wetland restoration (Wilson 2004). In year two, we will build and expand on these results in several important ways: • We are generalizing these results through the investigation of plant traits that consistently correspond to the patterns of establishment and vigor. • We are systematically compiling the results from year one and year two of this project into a public database. We are adding to this database findings from similar ecosystems, both in the Willamette Valley and elsewhere. • We are considering further the role of microsite variability on seedling establishment patterns. • We are synthesizing these results into scientific conclusions. • We are integrating these results, where there is sufficient support, into concrete and defensible management recommendations Our goal is to develop an ability to predict key aspects of prairie restoration performance, such as establishment rates, based on knowing species traits, site conditions, and maintenance. These predictions can then be converted into management recommendations, such as which species to sow and which site preparation and maintenance regimes should be followed to maximize native plant abundance and minimize non-native plant abundance at a given site. The two components of our project –plant traits and the database– are crucial to this goal. • Without the generalization that traits allow, understanding of wetland restoration increases slowly and expensively, one case study at a time. • The organization of the database will increase the power and efficiency of revealing the relationships between plant traits and plant performance. Perhaps even more important is the role of the database as a first step in developing a Web-based expert system for managers wishing to plan wetland restorations Title: Progress report II: Restoring prairies: A synthesis of studies on vegetation and invasive species in support of effective management (Year two) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Willamette Valley wetland and upland prairies are some of the most endangered ecosystems in the United States, and provide habitat for many federally listed species. Because these are dynamic systems, subject to ecological succession and invasion by aggressive non-native species, prairies require active management to maintain management goals. This is true of all Willamette Valley prairies, whether intact, degraded, or reestablished. Yet restoration and conservation efforts often lack experimental validation. Our overall objective for this project is to synthesize the scientific information now available relevant to the prairie restoration efforts of the West Eugene Wetlands project and, where there is sufficient support, develop concrete and defensible management recommendations Successful ecosystem restoration requires establishing and maintaining native plants. In turn, plant establishment hinges on having suitable environmental conditions, using species with adequate germination rates, and reducing competitive pressure from nonnative plants. In year one of this project, we synthesized the wealth of data in the West Eugene Wetlands establishment data set on plant abundance after sowing native species during wetland restoration (Wilson 2004). In year two, we will build and expand on these results in several important ways: • We are generalizing these results through the investigation of plant traits that consistently correspond to the patterns of establishment and vigor. • We are systematically compiling the results from year one and year two of this project into a public database. We are adding to this database findings from similar ecosystems, both in the Willamette Valley and elsewhere. • We are considering further the role of microsite variability on seedling establishment patterns. • We are synthesizing these results into scientific conclusions. • We are integrating these results, where there is sufficient support, into concrete and defensible management recommendations Our goal is to develop an ability to predict key aspects of prairie restoration performance, such as establishment rates, based on knowing species traits, site conditions, and maintenance. These predictions can then be converted into management recommendations, such as which species to sow and which site preparation and maintenance regimes should be followed to maximize native plant abundance and minimize non-native plant abundance at a given site. The two components of our project –plant traits and the database– are crucial to this goal. • Without the generalization that traits allow, understanding of wetland restoration increases slowly and expensively, one case study at a time. • The organization of the database will increase the power and efficiency of revealing the relationships between plant traits and plant performance. Perhaps even more important is the role of the database as a first step in developing a Web-based expert system for managers wishing to plan wetland restorations Close

• 4. [Article] Progress report [I]: Restoring prairies: A synthesis of studies on vegetation and invasive species in support of effective management (Year two)

  Willamette Valley wetland and upland prairies are some of the most endangered ecosystems in the United States, and provide habitat for many federally listed species. These are dynamic systems, subject ...

  Citation × Citation Citation Abstract Copy Title: Progress report [I]: Restoring prairies: A synthesis of studies on vegetation and invasive species in support of effective management (Year two) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Willamette Valley wetland and upland prairies are some of the most endangered ecosystems in the United States, and provide habitat for many federally listed species. These are dynamic systems, subject to ecological succession and invasion by aggressive non-native species, and require active management to maintain management goals. This is true of all Willamette Valley prairies, whether intact, degraded, or reestablished. Yet restoration and conservation efforts often lack experimental validation. Our overall objective is to synthesize the scientific information now available pertinent to the prairie restoration efforts of the West Eugene Wetlands Program (WEWP) and, where there is sufficient support, develop concrete and defensible management recommendations. Successful ecosystem restoration requires establishing and maintaining native plants. In turn, plant establishment hinges on having suitable environmental conditions, using species with adequate germination and growth rates, and reducing competitive pressure from non-native plants (Figure 1). In year one of this project, we synthesized the wealth of plant establishment data during wetland restoration in the West Eugene Wetlands Program. In year two, we are building and expanding on these results in several important ways: • We are generalizing these results through the investigation of plant traits (Table 1) that consistently correspond to the patterns of establishment and vigor (Figure 1). • We are systematically compiling the results from year one and year two of this project into a public database. We are adding to this database findings from similar ecosystems, both in the Willamette Valley and elsewhere. • We are considering further the role of microsite variability on seedling establishment patterns. • We are synthesizing these results into scientific conclusions. • We are integrating these results, where there is sufficient support, into concrete and defensible management recommendations Our goal is to develop an ability to predict key aspects of prairie restoration performance, such as establishment rates, based on species traits, site conditions, and maintenance. These predictions can then be restated as management recommendations, such as which species to sow and site preparation and maintenance regimes to follow to maximize native plant abundance and minimize non-native plant abundance at a given site. The two components of our project–plant traits and the database–are crucial to this goal. • Without the generalization that traits allow, understanding of wetland restoration increases slowly and expensively, one case study at a time. • The organization of the database will increase the power and efficiency of revealing the relationships between plant traits and plant performance. Perhaps even more important is the role of the database as a first step in developing a Web-based expert system for managers wishing to plan wetland restorations. Title: Progress report [I]: Restoring prairies: A synthesis of studies on vegetation and invasive species in support of effective management (Year two) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Willamette Valley wetland and upland prairies are some of the most endangered ecosystems in the United States, and provide habitat for many federally listed species. These are dynamic systems, subject to ecological succession and invasion by aggressive non-native species, and require active management to maintain management goals. This is true of all Willamette Valley prairies, whether intact, degraded, or reestablished. Yet restoration and conservation efforts often lack experimental validation. Our overall objective is to synthesize the scientific information now available pertinent to the prairie restoration efforts of the West Eugene Wetlands Program (WEWP) and, where there is sufficient support, develop concrete and defensible management recommendations. Successful ecosystem restoration requires establishing and maintaining native plants. In turn, plant establishment hinges on having suitable environmental conditions, using species with adequate germination and growth rates, and reducing competitive pressure from non-native plants (Figure 1). In year one of this project, we synthesized the wealth of plant establishment data during wetland restoration in the West Eugene Wetlands Program. In year two, we are building and expanding on these results in several important ways: • We are generalizing these results through the investigation of plant traits (Table 1) that consistently correspond to the patterns of establishment and vigor (Figure 1). • We are systematically compiling the results from year one and year two of this project into a public database. We are adding to this database findings from similar ecosystems, both in the Willamette Valley and elsewhere. • We are considering further the role of microsite variability on seedling establishment patterns. • We are synthesizing these results into scientific conclusions. • We are integrating these results, where there is sufficient support, into concrete and defensible management recommendations Our goal is to develop an ability to predict key aspects of prairie restoration performance, such as establishment rates, based on species traits, site conditions, and maintenance. These predictions can then be restated as management recommendations, such as which species to sow and site preparation and maintenance regimes to follow to maximize native plant abundance and minimize non-native plant abundance at a given site. The two components of our project–plant traits and the database–are crucial to this goal. • Without the generalization that traits allow, understanding of wetland restoration increases slowly and expensively, one case study at a time. • The organization of the database will increase the power and efficiency of revealing the relationships between plant traits and plant performance. Perhaps even more important is the role of the database as a first step in developing a Web-based expert system for managers wishing to plan wetland restorations. Close

• 5. [Article] Controlling woody vegetation in wetland prairies, 1994-1999

  Wetland prairies of the Willamette Valley, among the rarest of Oregon’s ecosystems, are threatened by invasion of woody species and non-native pest species. Because fire has been important in maintaining ...

  Citation × Citation Citation Abstract Copy Title: Controlling woody vegetation in wetland prairies, 1994-1999 Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Wetland prairies of the Willamette Valley, among the rarest of Oregon’s ecosystems, are threatened by invasion of woody species and non-native pest species. Because fire has been important in maintaining Willamette Valley prairies for at least 1000 years, prescribed burning is a top choice of managers for preventing encroachment of woody species. However, the effects of prescribed burning on present day wetland prairie communities, with their mix of native and non-native species, are not clear. Moreover, because strict governmental requirements for smoke management hinder prescribed burning, natural-area managers are considering alternatives to fire, like mowing and hand removal of woody plants. The present study explored the ecological interactions of a wetland prairie by experimentally testing the responses of burning, hand-removal of woody species, and mowing with removal of cut material on woody plants and key native and non-native grasses and forbs. We evaluated these perturbations for their effectiveness in meeting management objectives of reducing abundance of woody species, reducing or preventing an increase in abundance of nonnative pest species, and increasing or at least maintaining native species’ abundance. After three treatments periods (1994, 1996, and 1998) the following patterns emerged: • Woody species Burning and hand-removal consistently caused the greatest reduction in cover of woody species. Mowing with removal of cut material did not reduce the abundance of woody species compared to the control. As woody plant cover decreased, plant mortality increased, indicating that treatments influenced woody plant cover at least partially through changes in survival. • Native herbaceous species All management treatments consistently failed to significantly increase the cover of Deschampsia cespitosa, while burning decreased the number of inflorescences. As a group, native graminoid flowering consistently showed no significant responses to the management treatments. Although burning and hand-removal significantly increased the cover of native forbs as group after the second treatment period in 1997, native forbs showed no significant responses to treatments in 1999. • Non-native herbaceous species Response of non-native forb cover to management treatments has been inconsistent during the five year study period with no significant differences in 1995, significant reductions by burning and hand-removal in 1997, and increases with mowing in 1997. Mowing consistently increased flowering of nonnative graminoids as a group. Overall no treatment was clearly superior in fulfilling restoration objectives. Burning was effective in reducing woody cover and did not promote non-native herbaceous, but it reduced the flowering the dominant native grass, Deschampsia cespitosa. Hand-removal woody species was also effective at reducing woody cover and sometimes promoted the abundance of some native species at different times, but it also at times promoted non-native herbaceous species. Because mowing with removal of cut material was ineffective in reducing woody cover and tended to promote non-native herbaceous species, this treatment is not a recommended management strategy. Title: Controlling woody vegetation in wetland prairies, 1994-1999 Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Wetland prairies of the Willamette Valley, among the rarest of Oregon’s ecosystems, are threatened by invasion of woody species and non-native pest species. Because fire has been important in maintaining Willamette Valley prairies for at least 1000 years, prescribed burning is a top choice of managers for preventing encroachment of woody species. However, the effects of prescribed burning on present day wetland prairie communities, with their mix of native and non-native species, are not clear. Moreover, because strict governmental requirements for smoke management hinder prescribed burning, natural-area managers are considering alternatives to fire, like mowing and hand removal of woody plants. The present study explored the ecological interactions of a wetland prairie by experimentally testing the responses of burning, hand-removal of woody species, and mowing with removal of cut material on woody plants and key native and non-native grasses and forbs. We evaluated these perturbations for their effectiveness in meeting management objectives of reducing abundance of woody species, reducing or preventing an increase in abundance of nonnative pest species, and increasing or at least maintaining native species’ abundance. After three treatments periods (1994, 1996, and 1998) the following patterns emerged: • Woody species Burning and hand-removal consistently caused the greatest reduction in cover of woody species. Mowing with removal of cut material did not reduce the abundance of woody species compared to the control. As woody plant cover decreased, plant mortality increased, indicating that treatments influenced woody plant cover at least partially through changes in survival. • Native herbaceous species All management treatments consistently failed to significantly increase the cover of Deschampsia cespitosa, while burning decreased the number of inflorescences. As a group, native graminoid flowering consistently showed no significant responses to the management treatments. Although burning and hand-removal significantly increased the cover of native forbs as group after the second treatment period in 1997, native forbs showed no significant responses to treatments in 1999. • Non-native herbaceous species Response of non-native forb cover to management treatments has been inconsistent during the five year study period with no significant differences in 1995, significant reductions by burning and hand-removal in 1997, and increases with mowing in 1997. Mowing consistently increased flowering of nonnative graminoids as a group. Overall no treatment was clearly superior in fulfilling restoration objectives. Burning was effective in reducing woody cover and did not promote non-native herbaceous, but it reduced the flowering the dominant native grass, Deschampsia cespitosa. Hand-removal woody species was also effective at reducing woody cover and sometimes promoted the abundance of some native species at different times, but it also at times promoted non-native herbaceous species. Because mowing with removal of cut material was ineffective in reducing woody cover and tended to promote non-native herbaceous species, this treatment is not a recommended management strategy. Close

• 6. [Article] Increasing the abundance of rare native wetland prairie species

  Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species ...

  Citation × Citation Citation Abstract Copy Title: Increasing the abundance of rare native wetland prairie species Author: Goodridge, Jennifer, Wilson, Mark V., Clark, Deborah Louise, 1950- Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species are urgently needed, particularly those strategies that promote the regeneration of native species from seed. Fire may be an important factor in promoting regeneration of native species from seed because of its historical role in maintaining the prairie landscape. The study objectives were (1) to determine the effect of prescribed burning on regeneration of native species from seed, and (2) to establish predictive relationships between easily measured plant traits and seedling establishment rates in the field. The general approach was to sow seeds of target wetland prairie species during the fall into experimental field plots already established at the Danebo Wetland, Eugene, OR. Seedling establishment rates were then compared between burned and unburned plots the following spring. To establish predictive relationships these seedling establishment rates were related to selected seed and seedling traits measured under laboratory conditions. Overall seedling establishment rates showed no significant differences between burned (7.0%) and unburned plots (8.7%), although for the seven species showing positive responses to prescribed burning, the increase was approximately doubled in the burned plots. Burning significantly increased the seedling establishment rates of three species, Wyethia angustifolia, Grindelia integrifolia, and Danthonia californica. Seedling establishment significantly decreased with burning for one species, Sidalcea campestris. For three of the four endangered, threatened or rare species, Aster curtus, Horkelia congesta, and Sidalcea cusickii var. purpurea, seedling establishment rates were smaller in the burned plots compared to the unburned plots, although the differences were not significant. Lomatium bradshawii had no seedlings establish in either the burned or the unburned plots. Plant weight 7 days after germination was the best trait at predicting field seedling establishment rates for both the burned plots and the unburned plots, explaining a significant amount of variation in establishment rates: 70% for the burned plots and 45% for the unburned plots. This model could be used by managers to choose species for sowing in burned and unburned prairies or to estimate seeding rates at burned and unburned sites. Title: Increasing the abundance of rare native wetland prairie species Author: Goodridge, Jennifer, Wilson, Mark V., Clark, Deborah Louise, 1950- Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species are urgently needed, particularly those strategies that promote the regeneration of native species from seed. Fire may be an important factor in promoting regeneration of native species from seed because of its historical role in maintaining the prairie landscape. The study objectives were (1) to determine the effect of prescribed burning on regeneration of native species from seed, and (2) to establish predictive relationships between easily measured plant traits and seedling establishment rates in the field. The general approach was to sow seeds of target wetland prairie species during the fall into experimental field plots already established at the Danebo Wetland, Eugene, OR. Seedling establishment rates were then compared between burned and unburned plots the following spring. To establish predictive relationships these seedling establishment rates were related to selected seed and seedling traits measured under laboratory conditions. Overall seedling establishment rates showed no significant differences between burned (7.0%) and unburned plots (8.7%), although for the seven species showing positive responses to prescribed burning, the increase was approximately doubled in the burned plots. Burning significantly increased the seedling establishment rates of three species, Wyethia angustifolia, Grindelia integrifolia, and Danthonia californica. Seedling establishment significantly decreased with burning for one species, Sidalcea campestris. For three of the four endangered, threatened or rare species, Aster curtus, Horkelia congesta, and Sidalcea cusickii var. purpurea, seedling establishment rates were smaller in the burned plots compared to the unburned plots, although the differences were not significant. Lomatium bradshawii had no seedlings establish in either the burned or the unburned plots. Plant weight 7 days after germination was the best trait at predicting field seedling establishment rates for both the burned plots and the unburned plots, explaining a significant amount of variation in establishment rates: 70% for the burned plots and 45% for the unburned plots. This model could be used by managers to choose species for sowing in burned and unburned prairies or to estimate seeding rates at burned and unburned sites. Close

• 7. [Article] Controlling woody vegetation in wetland prairies, 1994-2001

  Wetland prairies of the Willamette Valley, among the rarest of Oregon’s ecosystems, are threatened by invasion of woody species and non-native pest species. Because fire has been important in maintaining ...

  Citation × Citation Citation Abstract Copy Title: Controlling woody vegetation in wetland prairies, 1994-2001 Author: Clark, Deborah Louise, 1950- Wetland prairies of the Willamette Valley, among the rarest of Oregon’s ecosystems, are threatened by invasion of woody species and non-native pest species. Because fire has been important in maintaining Willamette Valley prairies for at least 1000 years, prescribed burning is a top choice of managers for preventing encroachment of woody species. However, the effects of prescribed burning on present day wetland prairie communities, with their mix of native and non-native species, are not clear. Moreover, because strict governmental requirements for smoke management hinder prescribed burning, natural-area managers are considering alternatives to fire, like mowing and hand-removal of woody plants. The present study explored the ecological interactions of a wetland prairie by experimentally testing the responses of burning, hand-removal of woody species, and mowing with removal of cut material on woody plants and key native and non-native grasses and forbs. We evaluated these perturbations for their effectiveness in meeting management objectives of reducing abundance of woody species, reducing or preventing an increase in abundance of nonnative pest species, and increasing or at least maintaining native species’ abundance. After four treatments periods (1994, 1996, 1998, and 2000) the following patterns emerged: • Woody species Burning and hand-removal of woody plants every two years consistently decreased the cover of woody species, even with a gradual increase in the controls to over double 1994 levels. The change in woody cover after mowing with removal of cut material was not significantly different from that in the control. As woody plant cover decreased, plant mortality increased, indicating that treatments influenced woody plant cover at least partially through changes in survival. • Native herbaceous species None of the treatments had a significant effect after four treatment periods on the proportional change in cover or in number of inflorescences of Deschampsia cespitosa, although the change in number of inflorescences was consistently less than that in the control, including a significant decrease with burning in 1997. As a group, native graminoid species showed no significant differences in flowering response to treatments during any of the four treatment periods. However, burning and mowing consistently promoted flowering of Juncus tenuis. The cover of native forbs as a group was not significantly different from that of the control, with the exception of 1997, where cover increased with burning and hand-removal. Even though native forbs as a group have generally not shown significant differences, individual native forb species have shown positive responses to treatments: Sidalcea cusickii, spp. purpurea, Eriophyllum lanatum, and Sisyrinchium idahoensis. • Non-native herbaceous species Both hand-removal and mowing promoted flowering of non-native graminoids as a group. In contrast, burning maintained levels of flowering of non-native graminoids similar to that of the controls. Cover of non-native forbs as a group showed no significant treatment differences except for 1997, in which significant reductions in cover occurred after burning and hand-removal. The results to date show that prescribed burning is the best option of the three tested management treatments for achieving the restoration goals for native wetland prairies. Because mowing with removal of cut material was ineffective in reducing woody cover and tended to promote non-native herbaceous species, this treatment should be avoided. Title: Controlling woody vegetation in wetland prairies, 1994-2001 Author: Clark, Deborah Louise, 1950- Wetland prairies of the Willamette Valley, among the rarest of Oregon’s ecosystems, are threatened by invasion of woody species and non-native pest species. Because fire has been important in maintaining Willamette Valley prairies for at least 1000 years, prescribed burning is a top choice of managers for preventing encroachment of woody species. However, the effects of prescribed burning on present day wetland prairie communities, with their mix of native and non-native species, are not clear. Moreover, because strict governmental requirements for smoke management hinder prescribed burning, natural-area managers are considering alternatives to fire, like mowing and hand-removal of woody plants. The present study explored the ecological interactions of a wetland prairie by experimentally testing the responses of burning, hand-removal of woody species, and mowing with removal of cut material on woody plants and key native and non-native grasses and forbs. We evaluated these perturbations for their effectiveness in meeting management objectives of reducing abundance of woody species, reducing or preventing an increase in abundance of nonnative pest species, and increasing or at least maintaining native species’ abundance. After four treatments periods (1994, 1996, 1998, and 2000) the following patterns emerged: • Woody species Burning and hand-removal of woody plants every two years consistently decreased the cover of woody species, even with a gradual increase in the controls to over double 1994 levels. The change in woody cover after mowing with removal of cut material was not significantly different from that in the control. As woody plant cover decreased, plant mortality increased, indicating that treatments influenced woody plant cover at least partially through changes in survival. • Native herbaceous species None of the treatments had a significant effect after four treatment periods on the proportional change in cover or in number of inflorescences of Deschampsia cespitosa, although the change in number of inflorescences was consistently less than that in the control, including a significant decrease with burning in 1997. As a group, native graminoid species showed no significant differences in flowering response to treatments during any of the four treatment periods. However, burning and mowing consistently promoted flowering of Juncus tenuis. The cover of native forbs as a group was not significantly different from that of the control, with the exception of 1997, where cover increased with burning and hand-removal. Even though native forbs as a group have generally not shown significant differences, individual native forb species have shown positive responses to treatments: Sidalcea cusickii, spp. purpurea, Eriophyllum lanatum, and Sisyrinchium idahoensis. • Non-native herbaceous species Both hand-removal and mowing promoted flowering of non-native graminoids as a group. In contrast, burning maintained levels of flowering of non-native graminoids similar to that of the controls. Cover of non-native forbs as a group showed no significant treatment differences except for 1997, in which significant reductions in cover occurred after burning and hand-removal. The results to date show that prescribed burning is the best option of the three tested management treatments for achieving the restoration goals for native wetland prairies. Because mowing with removal of cut material was ineffective in reducing woody cover and tended to promote non-native herbaceous species, this treatment should be avoided. 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• 8. [Article] Native wetland, riparian, and upland plant communities and their biota in the Willamette Valley, Oregon

  As part of the Willamette Basin Geographic Initiative Program, the Environmental Protection Agency (EPA) funded The Nature Conservancy of Oregon to inventory, classify, and map native wetland and riparian ...

  Citation × Citation Citation Abstract Copy Title: Native wetland, riparian, and upland plant communities and their biota in the Willamette Valley, Oregon Author: Alverson, Edward R., VanderSchaaf, Dick, Kagan, James S., Christy, John A., Titus, John H. As part of the Willamette Basin Geographic Initiative Program, the Environmental Protection Agency (EPA) funded The Nature Conservancy of Oregon to inventory, classify, and map native wetland and riparian plant communities and their threatened biota in the Willamette Valley. Between October 1994 and September 1996, we evaluated 172 wetland and riparian sites throughout the Willamette Valley. A site is a stream or river reach or wetland area that was inventoried at one to many locations. Of these sites, 21 are high-quality remnants important for future protection and restoration efforts. We identified 153 natural communities as occurring in native wetland and riparian habitats, of which 101 are new to the plant community classification of the Oregon Natural Heritage Program. Twenty-six species of rare animals and 23 species of rare plants occur in the Willamette Valley. Thirty-two species of rare plants and animals appear to be directly dependent on wetland and riparian communities in the Willamette Valley, and twenty-two species are dependent on upland communities in the Willamette Valley. Mapping of presettlement vegetation in the Willamette Valley indicates that 456,119 hectares (1,127,071 ac) of wetland and riparian habitat have been lost overall, with 12 communities impacted in particular. As for uplands, 732,432 hectares (1,809,841 ac) of habitat have been lost overall, with 7 natural communities impacted in particular. We recommend local citizen involvement, land purchases and restoration as means of protecting and restoring remnant ecosystems and their biota in the Willamette Valley. Title: Native wetland, riparian, and upland plant communities and their biota in the Willamette Valley, Oregon Author: Alverson, Edward R., VanderSchaaf, Dick, Kagan, James S., Christy, John A., Titus, John H. As part of the Willamette Basin Geographic Initiative Program, the Environmental Protection Agency (EPA) funded The Nature Conservancy of Oregon to inventory, classify, and map native wetland and riparian plant communities and their threatened biota in the Willamette Valley. Between October 1994 and September 1996, we evaluated 172 wetland and riparian sites throughout the Willamette Valley. A site is a stream or river reach or wetland area that was inventoried at one to many locations. Of these sites, 21 are high-quality remnants important for future protection and restoration efforts. We identified 153 natural communities as occurring in native wetland and riparian habitats, of which 101 are new to the plant community classification of the Oregon Natural Heritage Program. Twenty-six species of rare animals and 23 species of rare plants occur in the Willamette Valley. Thirty-two species of rare plants and animals appear to be directly dependent on wetland and riparian communities in the Willamette Valley, and twenty-two species are dependent on upland communities in the Willamette Valley. Mapping of presettlement vegetation in the Willamette Valley indicates that 456,119 hectares (1,127,071 ac) of wetland and riparian habitat have been lost overall, with 12 communities impacted in particular. As for uplands, 732,432 hectares (1,809,841 ac) of habitat have been lost overall, with 7 natural communities impacted in particular. We recommend local citizen involvement, land purchases and restoration as means of protecting and restoring remnant ecosystems and their biota in the Willamette Valley. Close

• 9. [Article] Environmental indicators for the Oregon plan for salmon and watersheds

  The INR worked with the Oregon Department of Environmental Quality, the Oregon Department of Fish and Wildlife, and the federal Environmental Protection Agency to propose an integrated study design for ...

  Citation × Citation Citation Abstract Copy Title: Environmental indicators for the Oregon plan for salmon and watersheds Author: Dent, Liz, Salwasser, Hal, Achterman, Gail The INR worked with the Oregon Department of Environmental Quality, the Oregon Department of Fish and Wildlife, and the federal Environmental Protection Agency to propose an integrated study design for collecting data on Native Fish, Indexes of Biotic Integrity and Water Quality, and Riparian Area Condition and Function. Estimated costs are provided at various scales. The reporting time frame will depend on the indicator and the sample design. A reporting time frame of 5–10 years would allow ecosystems to respond perceptibly to both natural disturbances and management activities and policies. Shorter reporting periods are likely to reveal very little change and yet increase costs. Title: Environmental indicators for the Oregon plan for salmon and watersheds Author: Dent, Liz, Salwasser, Hal, Achterman, Gail The INR worked with the Oregon Department of Environmental Quality, the Oregon Department of Fish and Wildlife, and the federal Environmental Protection Agency to propose an integrated study design for collecting data on Native Fish, Indexes of Biotic Integrity and Water Quality, and Riparian Area Condition and Function. Estimated costs are provided at various scales. The reporting time frame will depend on the indicator and the sample design. A reporting time frame of 5–10 years would allow ecosystems to respond perceptibly to both natural disturbances and management activities and policies. Shorter reporting periods are likely to reveal very little change and yet increase costs. Close