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• 21. [Article] A Practitioner’s Handbook: Optimizing Conservation and Improving Mitigation Through the Use of Progressive Approaches

  The information contained in this report was prepared as part of NCHRP Project 25-25, Task 67, National Cooperative Highway Research Program, Transportation Research Board. SPECIAL NOTE: This report IS ...

  Citation × Citation Citation Abstract Copy Title: A Practitioner’s Handbook: Optimizing Conservation and Improving Mitigation Through the Use of Progressive Approaches Author: NatureServe, Cambridge Systematics, Inc., Institute for Natural Resources, Resources for the Future, Environmental Law Institute The information contained in this report was prepared as part of NCHRP Project 25-25, Task 67, National Cooperative Highway Research Program, Transportation Research Board. SPECIAL NOTE: This report IS NOT an official publication of the National Cooperative Highway Research Program, Transportation Research Board, National Research Council, or The National Academies. Title: A Practitioner’s Handbook: Optimizing Conservation and Improving Mitigation Through the Use of Progressive Approaches Author: NatureServe, Cambridge Systematics, Inc., Institute for Natural Resources, Resources for the Future, Environmental Law Institute The information contained in this report was prepared as part of NCHRP Project 25-25, Task 67, National Cooperative Highway Research Program, Transportation Research Board. SPECIAL NOTE: This report IS NOT an official publication of the National Cooperative Highway Research Program, Transportation Research Board, National Research Council, or The National Academies. Close

• 22. [Article] Restoration of native upland prairies: Habitat for Fender’s blue butterfly (Icaricia icarioides fenderi)

  Our project goal is to promote the abundance of the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) by recreating upland prairie habitat in former agricultural land at Finley National ...

  Citation × Citation Citation Abstract Copy Title: Restoration of native upland prairies: Habitat for Fender’s blue butterfly (Icaricia icarioides fenderi) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Our project goal is to promote the abundance of the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) by recreating upland prairie habitat in former agricultural land at Finley National Wildlife Refuge, Corvallis, Oregon. To achieve this goal we initiated the following three studies. Study One: Experimental Investigation on the Effectiveness of Restoration Treatments Our approach was to set up experimental field plots in a former agricultural field into which we sowed seeds of native grasses and dicots in the fall for two years, 2003 and 2004. Objective one: Investigate the effect of carbon banding on abundance of sowed native species and non-native species. Carbon banding is a treatment used by Willamette Valley grass seed farmers to promote seedling establishment of agricultural grasses and inhibit seedling establishment of weeds. Objective two: Investigate the effect of the sowing sequence of native dicot and grass species on the abundance and species richness of the sowed species. Our experiments were designed to test the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. Objective three: Investigate the effect of the sowing sequence of the native dicot and grass species on the abundance of non-native species. Study Two: Monoculture Sowing of Native Species Compare the cover of non-native species and the cover of native species one and two years after sowing native species in monocultures. Study Three: Buffer Sowing of Native Grasses Monitor the abundance of the native grasses sowed in the buffer areas outside the experimental plots. Carbon banding had no significant effect on cover of non-native species or on cover and species richness of sowed native dicots or grasses after both the first and second growing seasons. However, carbon banding tended to reduce the cover of the annual Clarkia rhomboidea after the first growing season. Our results supported the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. The sowing sequences tested did not affect cover and species richness of grasses but did affect cover and species richness of dicot species. Both dicot cover and dicot species richness were greater when sowed a year ahead of the grasses. Eriophyllum lanatum had significantly greater cover when sowed a year before the grasses. Average cover of sowed dicots was significantly greater when dicots were sowed with grasses compared to when dicots were sowed into a year-old stand of grasses. In particular, Madia gracilis and Prunella vulgaris var. lanceolata had less cover when sowed into the existing stand of grass. Species richness of all native species (grasses + dicots) was significantly less when dicots were sowed into a year-old stand of grasses. However, total cover and species richness of sowed native species (grasses + dicots) were not significantly different whether dicots were sowed a year ahead of the grasses or whether dicots and grasses were sowed together. Average cover of sowed native dicots after two years was always greater than the cover of sowed native grasses except when dicots were sowed a year after the grasses. After two growing seasons, non-native cover did not significantly vary among the three sowing sequences of sowing grasses and dicots at the same time, sowing grasses into existing dicot vegetation, and sowing grasses into existing dicot vegetation. The first year after sowing the monocultures (Study two), Collinsia grandiflora had the highest cover, greatly surpassing the next top performers, Sanguisorba occidentalis and Madia gracilis, all of which are annual species. In general, the cover of individual species sowed in monocultures decreased the second year after sowing. Only seven species, all of which were perennials, out of the 26 sowed species increased in cover. Two of these species Eriophyllum lanatum and Prunella vulgaris var. lanceolata were the top performers for 2005, but their cover did not reach the levels of the top performers in 2004. Title: Restoration of native upland prairies: Habitat for Fender’s blue butterfly (Icaricia icarioides fenderi) Author: Wilson, Mark V., Clark, Deborah Louise, 1950- Our project goal is to promote the abundance of the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) by recreating upland prairie habitat in former agricultural land at Finley National Wildlife Refuge, Corvallis, Oregon. To achieve this goal we initiated the following three studies. Study One: Experimental Investigation on the Effectiveness of Restoration Treatments Our approach was to set up experimental field plots in a former agricultural field into which we sowed seeds of native grasses and dicots in the fall for two years, 2003 and 2004. Objective one: Investigate the effect of carbon banding on abundance of sowed native species and non-native species. Carbon banding is a treatment used by Willamette Valley grass seed farmers to promote seedling establishment of agricultural grasses and inhibit seedling establishment of weeds. Objective two: Investigate the effect of the sowing sequence of native dicot and grass species on the abundance and species richness of the sowed species. Our experiments were designed to test the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. Objective three: Investigate the effect of the sowing sequence of the native dicot and grass species on the abundance of non-native species. Study Two: Monoculture Sowing of Native Species Compare the cover of non-native species and the cover of native species one and two years after sowing native species in monocultures. Study Three: Buffer Sowing of Native Grasses Monitor the abundance of the native grasses sowed in the buffer areas outside the experimental plots. Carbon banding had no significant effect on cover of non-native species or on cover and species richness of sowed native dicots or grasses after both the first and second growing seasons. However, carbon banding tended to reduce the cover of the annual Clarkia rhomboidea after the first growing season. Our results supported the hypothesis that our native grasses are more aggressive than the target native dicots in the initial stages of restoration. The sowing sequences tested did not affect cover and species richness of grasses but did affect cover and species richness of dicot species. Both dicot cover and dicot species richness were greater when sowed a year ahead of the grasses. Eriophyllum lanatum had significantly greater cover when sowed a year before the grasses. Average cover of sowed dicots was significantly greater when dicots were sowed with grasses compared to when dicots were sowed into a year-old stand of grasses. In particular, Madia gracilis and Prunella vulgaris var. lanceolata had less cover when sowed into the existing stand of grass. Species richness of all native species (grasses + dicots) was significantly less when dicots were sowed into a year-old stand of grasses. However, total cover and species richness of sowed native species (grasses + dicots) were not significantly different whether dicots were sowed a year ahead of the grasses or whether dicots and grasses were sowed together. Average cover of sowed native dicots after two years was always greater than the cover of sowed native grasses except when dicots were sowed a year after the grasses. After two growing seasons, non-native cover did not significantly vary among the three sowing sequences of sowing grasses and dicots at the same time, sowing grasses into existing dicot vegetation, and sowing grasses into existing dicot vegetation. The first year after sowing the monocultures (Study two), Collinsia grandiflora had the highest cover, greatly surpassing the next top performers, Sanguisorba occidentalis and Madia gracilis, all of which are annual species. In general, the cover of individual species sowed in monocultures decreased the second year after sowing. Only seven species, all of which were perennials, out of the 26 sowed species increased in cover. Two of these species Eriophyllum lanatum and Prunella vulgaris var. lanceolata were the top performers for 2005, but their cover did not reach the levels of the top performers in 2004. Close

• 23. [Article] Astragalus peckii Population Establishment: Developing Protocols for Seed Germination, Seedling Cultivation, and Planting

  Astragalus peckii Piper is a threatened Oregon endemic in the pea family (Fabaceae). This species faces extinction due to loss of habitat. Recovery efforts include augmenting existing populations and creating ...

  Citation × Citation Citation Abstract Copy Title: Astragalus peckii Population Establishment: Developing Protocols for Seed Germination, Seedling Cultivation, and Planting Author: Pearson, Tabitha Astragalus peckii Piper is a threatened Oregon endemic in the pea family (Fabaceae). This species faces extinction due to loss of habitat. Recovery efforts include augmenting existing populations and creating new ones. The purpose of this study was to determine the best methodology for population augmentation of Astragalus peckii by evaluating methodologies for 1) seed germination and seedling cultivation, and 2) transplant survival and seed emergence. Older seeds required manual scarification to induce germination while younger seeds germinated without treatment. Seedlings were placed in three soil treatments with varying ratios of potting mix and native soil. Seedlings experienced high rates of mortality unrelated to treatment. Seeds and seedlings were planted in the fall along four transects of varying disturbance and previous species occupation. Spring survival rates provided little evidence for an increase in population size of Astragalus peckii in the four transects after planting. Title: Astragalus peckii Population Establishment: Developing Protocols for Seed Germination, Seedling Cultivation, and Planting Author: Pearson, Tabitha Astragalus peckii Piper is a threatened Oregon endemic in the pea family (Fabaceae). This species faces extinction due to loss of habitat. Recovery efforts include augmenting existing populations and creating new ones. The purpose of this study was to determine the best methodology for population augmentation of Astragalus peckii by evaluating methodologies for 1) seed germination and seedling cultivation, and 2) transplant survival and seed emergence. Older seeds required manual scarification to induce germination while younger seeds germinated without treatment. Seedlings were placed in three soil treatments with varying ratios of potting mix and native soil. Seedlings experienced high rates of mortality unrelated to treatment. Seeds and seedlings were planted in the fall along four transects of varying disturbance and previous species occupation. Spring survival rates provided little evidence for an increase in population size of Astragalus peckii in the four transects after planting. Close

• 24. [Article] Final report: Restoration of Fender’s blue butterfly and its prairie ecosystem: Management applications of fire to Baskett Slough NWR

  We tested the recolonization ability of the Fender’s blue butterfly and monitored the vegetation response to a management-scale prescribed fire at the Baskett Slough National Wildlife Refuge, western Oregon. ...

  Citation × Citation Citation Abstract Copy Title: Final report: Restoration of Fender’s blue butterfly and its prairie ecosystem: Management applications of fire to Baskett Slough NWR Author: Wilson, Mark V., Clark, Deborah Louise, 1950- We tested the recolonization ability of the Fender’s blue butterfly and monitored the vegetation response to a management-scale prescribed fire at the Baskett Slough National Wildlife Refuge, western Oregon. The prescribed fire successfully cut shrub cover in half, but also reduced the size of Festuca roemeri, a dominant native grass. Although the fire killed all Fender’s blue butterfly larvae, as expected, adult females were able to recolonize the burned area from a nearby, unburned patch. These results support predictions that the Fender’s blue butterfly can recolonize burned areas for a distance of at least 100 m. Title: Final report: Restoration of Fender’s blue butterfly and its prairie ecosystem: Management applications of fire to Baskett Slough NWR Author: Wilson, Mark V., Clark, Deborah Louise, 1950- We tested the recolonization ability of the Fender’s blue butterfly and monitored the vegetation response to a management-scale prescribed fire at the Baskett Slough National Wildlife Refuge, western Oregon. The prescribed fire successfully cut shrub cover in half, but also reduced the size of Festuca roemeri, a dominant native grass. Although the fire killed all Fender’s blue butterfly larvae, as expected, adult females were able to recolonize the burned area from a nearby, unburned patch. These results support predictions that the Fender’s blue butterfly can recolonize burned areas for a distance of at least 100 m. Close

• 25. [Article] Effects of Soil Nutrients and Fire on Seedling Establishment of Native Prairie Species

  We sought to determine 1) the relationship between seedling establishment rates of target native prairie species and field levels of three soil nutrients (phosphate, nitrate, and ammonium) recorded in ...

  Citation × Citation Citation Abstract Copy Title: Effects of Soil Nutrients and Fire on Seedling Establishment of Native Prairie Species Author: Clark, Deborah Louise, 1950- We sought to determine 1) the relationship between seedling establishment rates of target native prairie species and field levels of three soil nutrients (phosphate, nitrate, and ammonium) recorded in fall, winter, and summer, 2) the effect of fire on these three nutrients, and 3) the overall effect of fire on seedling establishment rates of the target native prairie species. Seedling establishment rates were not significantly correlated with soil nitrate or ammonium. Phosphate was significantly correlated with seedling establishment rates but the direction and strength of the relationship depended on the species, with three species showing positive relationships and three species showing negative relationships. Soil phosphate increased significantly in the burned plots compared to the unburned plots, soil ammonium decreased significantly in the burned plots, and soil nitrate showed no significant differences. These nutrient patterns successfully predicted the overall fire effects on seedling establishment in a separate experiment. The three species with positive correlations between seedling establishment and phosphate had greater seedling establishment rates in the burned plots compared to the unburned plots (two significantly, P≤0.1), and the three species with negative correlations had fewer seeds establish in the burned plots (two significantly (P ≤ 0.1). Title: Effects of Soil Nutrients and Fire on Seedling Establishment of Native Prairie Species Author: Clark, Deborah Louise, 1950- We sought to determine 1) the relationship between seedling establishment rates of target native prairie species and field levels of three soil nutrients (phosphate, nitrate, and ammonium) recorded in fall, winter, and summer, 2) the effect of fire on these three nutrients, and 3) the overall effect of fire on seedling establishment rates of the target native prairie species. Seedling establishment rates were not significantly correlated with soil nitrate or ammonium. Phosphate was significantly correlated with seedling establishment rates but the direction and strength of the relationship depended on the species, with three species showing positive relationships and three species showing negative relationships. Soil phosphate increased significantly in the burned plots compared to the unburned plots, soil ammonium decreased significantly in the burned plots, and soil nitrate showed no significant differences. These nutrient patterns successfully predicted the overall fire effects on seedling establishment in a separate experiment. The three species with positive correlations between seedling establishment and phosphate had greater seedling establishment rates in the burned plots compared to the unburned plots (two significantly, P≤0.1), and the three species with negative correlations had fewer seeds establish in the burned plots (two significantly (P ≤ 0.1). Close

• 26. [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

• 27. [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

• 28. [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

• 29. [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

• 30. [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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