Search

Search Results

• 1. [Article] Traits, neighbors, and species performance in prairie restoration

  Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial ...

  Citation × Citation Citation Abstract Copy Title: Traits, neighbors, and species performance in prairie restoration Author: Roberts, R. E., Wilson, Mark V., Clark, Deborah Louise, 1950- Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial forbs, and grasses? Do the relationships between traits and performance depend on neighboring functional groups? Location: A former agricultural field, being restored to native upland prairie, in the Willamette Valley of western Oregon USA. Methods: Twenty-eight native species, representing three functional groups, were sown in seven different combinations. The following summer the performance of each species was measured. Eleven functional traits were measured from plants in the laboratory and in the field. Correlations between individual traits and performance variables were measured and stepwise regression techniques were used to determine which sets of traits were most strongly related to performance. Results: Sets of traits explained up to 56% of variation in cover, and up to 48% of variation in establishment frequency. The relationships between traits and performance were influenced by functional group identity, and the functional group identity of neighboring species also influenced species’ cover and the relationships between traits and cover. Species’ establishment rate in monoculture was the trait most strongly correlated to both establishment and cover in mixtures. In multi-trait models, annual forb functional group identity was strongly related to establishment in mixtures, and height, leaf weight ratio at 7 days, and seed mass were strongly related to cover. Conclusions: Based on the strength of the statistical models, multiple-trait models should be a useful way of predicting the performance of species prior to sowing in restoration. The functional group identity of each species as well as the other species being sown may need to be taken into account when making predictions. Title: Traits, neighbors, and species performance in prairie restoration Author: Roberts, R. E., Wilson, Mark V., Clark, Deborah Louise, 1950- Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial forbs, and grasses? Do the relationships between traits and performance depend on neighboring functional groups? Location: A former agricultural field, being restored to native upland prairie, in the Willamette Valley of western Oregon USA. Methods: Twenty-eight native species, representing three functional groups, were sown in seven different combinations. The following summer the performance of each species was measured. Eleven functional traits were measured from plants in the laboratory and in the field. Correlations between individual traits and performance variables were measured and stepwise regression techniques were used to determine which sets of traits were most strongly related to performance. Results: Sets of traits explained up to 56% of variation in cover, and up to 48% of variation in establishment frequency. The relationships between traits and performance were influenced by functional group identity, and the functional group identity of neighboring species also influenced species’ cover and the relationships between traits and cover. Species’ establishment rate in monoculture was the trait most strongly correlated to both establishment and cover in mixtures. In multi-trait models, annual forb functional group identity was strongly related to establishment in mixtures, and height, leaf weight ratio at 7 days, and seed mass were strongly related to cover. Conclusions: Based on the strength of the statistical models, multiple-trait models should be a useful way of predicting the performance of species prior to sowing in restoration. The functional group identity of each species as well as the other species being sown may need to be taken into account when making predictions. Close

• 2. [Article] Plant traits – a tool for restoration?

  Question: Most results of restoration efforts are species-specific and/or site-specific and therefore are not general enough to be easily applied to other species and other sites. Our research addresses ...

  Citation × Citation Citation Abstract Copy Title: Plant traits – a tool for restoration? Author: Wilson, Mark V., Kaye, Thomas N., Roberts, Rachel, Dunwiddie, Peter W., Clark, Deborah Louise, 1950-, Stanley, Amanda Question: Most results of restoration efforts are species-specific and/or site-specific and therefore are not general enough to be easily applied to other species and other sites. Our research addresses the issue of species-specific results by investigating the feasibility of using plant traits instead of taxonomic species to characterize species responses to restoration treatments. Specifically, we test the explanatory power of plant traits, one necessary prerequisite for the development of predictive and general plant trait models. Location: Ten remnant bunchgrass prairie sites in the Pacific Northwest of North America (Oregon and Washington, USA; British Columbia, Canada). Methods: We developed two types of quantitative models for each of 10 prairie restoration sites: 1) plant trait models, which related plant traits to species field responses following restoration management treatments, and 2) species identity models, which related species taxonomic identity to species field responses following restoration management treatments. Species identity models determined the maximum amount of variability of field responses that can be explained by differences in individual species’ responses to management treatments. Plant trait models determined what proportion of this explanatory power can be attributed to plant traits. This approach contrasts with approaches often used in other plant trait studies that describe how traits vary with environmental conditions. Specifically, we used these two models to address the following questions: 1) How much of the variability in field responses of plants to restoration management treatments is explained by plant traits? 2) How well do plant traits explain the variability of field responses following restoration management treatments compared to models relating field responses to species identity? Our approach was to measure two aspects of explanatory power: R2 (variability explained) and AIC (a measure of model fit that accounts for parsimony, i.e., how well a model fits the data with relatively few explanatory variables). Results: 1) The plant trait models (relating plant traits with plant field responses) explained much of the variability within each of the ten restoration sites, with R2 values ranging between 31% and 69%. 2) The species identity models (relating species taxonomic identity with plant field responses) explained between 47% and 74% of variability in field performance (R2). Thus, the plant trait models explained nearly as much variability as the species identity models. In seven out of nine sites, the plant trait models were superior to the species identity models as measured by AIC; that is, the trait models did well at explaining variability with less model complexity (i.e., fewer explanatory variables). Conclusion: Development of general and predictive plant trait models is a multi-step process. Strong explanatory power by plant trait models, both on an absolute scale and as compared to species identity models, supports the feasibility of using plant traits instead of species taxonomic identity as a common language to characterize plant field responses to restoration treatments. Such high explanatory power is one necessary pre-requisite for the development of predictive and general plant trait models. Our results also indicate that the plant trait models are site-specific even though all sites were upland bunchgrass remnant prairies. We discuss the next steps in the development of more general and predictive models: incorporating environmental factors into the plant trait models to address the issue of site-specificity and testing the power of these models to predict vegetation responses. Title: Plant traits – a tool for restoration? Author: Wilson, Mark V., Kaye, Thomas N., Roberts, Rachel, Dunwiddie, Peter W., Clark, Deborah Louise, 1950-, Stanley, Amanda Question: Most results of restoration efforts are species-specific and/or site-specific and therefore are not general enough to be easily applied to other species and other sites. Our research addresses the issue of species-specific results by investigating the feasibility of using plant traits instead of taxonomic species to characterize species responses to restoration treatments. Specifically, we test the explanatory power of plant traits, one necessary prerequisite for the development of predictive and general plant trait models. Location: Ten remnant bunchgrass prairie sites in the Pacific Northwest of North America (Oregon and Washington, USA; British Columbia, Canada). Methods: We developed two types of quantitative models for each of 10 prairie restoration sites: 1) plant trait models, which related plant traits to species field responses following restoration management treatments, and 2) species identity models, which related species taxonomic identity to species field responses following restoration management treatments. Species identity models determined the maximum amount of variability of field responses that can be explained by differences in individual species’ responses to management treatments. Plant trait models determined what proportion of this explanatory power can be attributed to plant traits. This approach contrasts with approaches often used in other plant trait studies that describe how traits vary with environmental conditions. Specifically, we used these two models to address the following questions: 1) How much of the variability in field responses of plants to restoration management treatments is explained by plant traits? 2) How well do plant traits explain the variability of field responses following restoration management treatments compared to models relating field responses to species identity? Our approach was to measure two aspects of explanatory power: R2 (variability explained) and AIC (a measure of model fit that accounts for parsimony, i.e., how well a model fits the data with relatively few explanatory variables). Results: 1) The plant trait models (relating plant traits with plant field responses) explained much of the variability within each of the ten restoration sites, with R2 values ranging between 31% and 69%. 2) The species identity models (relating species taxonomic identity with plant field responses) explained between 47% and 74% of variability in field performance (R2). Thus, the plant trait models explained nearly as much variability as the species identity models. In seven out of nine sites, the plant trait models were superior to the species identity models as measured by AIC; that is, the trait models did well at explaining variability with less model complexity (i.e., fewer explanatory variables). Conclusion: Development of general and predictive plant trait models is a multi-step process. Strong explanatory power by plant trait models, both on an absolute scale and as compared to species identity models, supports the feasibility of using plant traits instead of species taxonomic identity as a common language to characterize plant field responses to restoration treatments. Such high explanatory power is one necessary pre-requisite for the development of predictive and general plant trait models. Our results also indicate that the plant trait models are site-specific even though all sites were upland bunchgrass remnant prairies. We discuss the next steps in the development of more general and predictive models: incorporating environmental factors into the plant trait models to address the issue of site-specificity and testing the power of these models to predict vegetation responses. Close

• 3. [Article] Final report [year one]: Control of Brachypodium sylvaticum and restoration of rare native upland prairie habitat at Butterfly Meadows, Benton County ODA 1342 GR

  Our project goal is to protect and restore rare Willamette Valley upland prairie habitat at Butterfly Meadows (Benton County) from invasion by the noxious weed Brachypodium sylvaticum (false brome). Native ...

  Citation × Citation Citation Abstract Copy Title: Final report [year one]: Control of Brachypodium sylvaticum and restoration of rare native upland prairie habitat at Butterfly Meadows, Benton County ODA 1342 GR Author: Johnson, Deborah, Pfund, Fred, Hammond, Paul, Wilson, Mark V., Vomocil, Marc, Kaye, Tom, Clark, Deborah Louise, 1950-, Kelpsas, Bruce Our project goal is to protect and restore rare Willamette Valley upland prairie habitat at Butterfly Meadows (Benton County) from invasion by the noxious weed Brachypodium sylvaticum (false brome). Native prairies, which once dominated the landscape of the Willamette Valley, are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. One of the largest remaining parcels of native upland prairie, Butterfly Meadows (Benton County), is being invaded by Brachypodium sylvaticum. This site is one of the three most important remaining habitats for the Fender’s blue butterfly and Kincaid’s lupine, listed as Endangered and Threatened respectively. We propose to develop and implement herbicide treatments that control Brachypodium sylvaticum without harming native prairie vegetation. We will also develop and implement measures to reestablish native species from seed after removal of Brachypodium sylvaticum. Conifers and mature shrubs that have encroached on the meadow, both on the edge and in the complex, will be removed by mechanical means or girdling. We propose to construct a buffer zone between the boundary of Butterfly Meadows and the neighboring intact forest and recently clear-cut areas, which are continuing sources of seed of Brachypodium sylvaticum invading Butterfly Meadows. This buffer zone will extend into both Starker Forest owned portions and OSU owned portions. To determine the success of control of Brachypodium sylvaticum and woody species and restoration of native vegetation, we will monitor changes in abundance of Brachypodium sylvaticum, woody species, and native vegetation. We will use monitoring results to adjust future Brachypodium sylvaticum control measures and native vegetation restoration measures as needed. Title: Final report [year one]: Control of Brachypodium sylvaticum and restoration of rare native upland prairie habitat at Butterfly Meadows, Benton County ODA 1342 GR Author: Johnson, Deborah, Pfund, Fred, Hammond, Paul, Wilson, Mark V., Vomocil, Marc, Kaye, Tom, Clark, Deborah Louise, 1950-, Kelpsas, Bruce Our project goal is to protect and restore rare Willamette Valley upland prairie habitat at Butterfly Meadows (Benton County) from invasion by the noxious weed Brachypodium sylvaticum (false brome). Native prairies, which once dominated the landscape of the Willamette Valley, are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. One of the largest remaining parcels of native upland prairie, Butterfly Meadows (Benton County), is being invaded by Brachypodium sylvaticum. This site is one of the three most important remaining habitats for the Fender’s blue butterfly and Kincaid’s lupine, listed as Endangered and Threatened respectively. We propose to develop and implement herbicide treatments that control Brachypodium sylvaticum without harming native prairie vegetation. We will also develop and implement measures to reestablish native species from seed after removal of Brachypodium sylvaticum. Conifers and mature shrubs that have encroached on the meadow, both on the edge and in the complex, will be removed by mechanical means or girdling. We propose to construct a buffer zone between the boundary of Butterfly Meadows and the neighboring intact forest and recently clear-cut areas, which are continuing sources of seed of Brachypodium sylvaticum invading Butterfly Meadows. This buffer zone will extend into both Starker Forest owned portions and OSU owned portions. To determine the success of control of Brachypodium sylvaticum and woody species and restoration of native vegetation, we will monitor changes in abundance of Brachypodium sylvaticum, woody species, and native vegetation. We will use monitoring results to adjust future Brachypodium sylvaticum control measures and native vegetation restoration measures as needed. Close

• 4. [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

• 5. [Article] Promoting regeneration of native species In Willamette Valley upland prairies

  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: Promoting regeneration of native species In Willamette Valley upland prairies Author: 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. The focus of this investigation was to address this need. The general approach was to sow seeds of native species into experimental field plots, which had been burned once, burned repeatedly, mowed, or unmanaged at three sites at Baskett Slough National Wildlife Refuge. Seedling numbers were then counted one growing season after sowing. To investigate mechanisms for the regeneration responses of species to management treatments, selected abiotic and biotic factors potentially important for seed regeneration were measured in the field plots. Seedling establishment rates in unmanaged plots were relatively small, averaging 9.7% for all three sites. Only one species, Danthonia californica, showed a positive response to the mowing treatment. Of the 13 species sowed in the burn plots, six species (Bromus carinatus, Elymus glacus, Festuca roemeri/rubra, Clarkia quadrivulera, Prunella vulgaris, Sidalcea campestris) had significant more seedlings in the burn plots compared to the unmanaged plots. Seedling establishment of two species, Danthonia californica and Potentilla gracilis, was significantly lower with burn treatments. The other five species showed no significant responses to the burn treatments: Carex tumicola, Calochortus tolmiei, Zygadensus venenosus, Balsamorhiza deltoidea, and Agoseris grandilflora. The strongest fire effects were generally in plots that had been burned only once, rather than plots burned more than once. Abundance of litter and vegetation were the factors that were most often related, both positively and negatively, with seedling establishment rates. Based on the results of this investigation, prescribed burning, rather than mowing, is a more viable management option to promote regeneration of native species from seed in upland prairies. However, prescribed burning must be used with caution as it can reduce seedling establishment rates for some species. Sowing seeds in unmanaged sites is an option, but sowing rates need to be high to compensate for the small seedling establishment rates in unmanaged prairies. Title: Promoting regeneration of native species In Willamette Valley upland prairies Author: 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. The focus of this investigation was to address this need. The general approach was to sow seeds of native species into experimental field plots, which had been burned once, burned repeatedly, mowed, or unmanaged at three sites at Baskett Slough National Wildlife Refuge. Seedling numbers were then counted one growing season after sowing. To investigate mechanisms for the regeneration responses of species to management treatments, selected abiotic and biotic factors potentially important for seed regeneration were measured in the field plots. Seedling establishment rates in unmanaged plots were relatively small, averaging 9.7% for all three sites. Only one species, Danthonia californica, showed a positive response to the mowing treatment. Of the 13 species sowed in the burn plots, six species (Bromus carinatus, Elymus glacus, Festuca roemeri/rubra, Clarkia quadrivulera, Prunella vulgaris, Sidalcea campestris) had significant more seedlings in the burn plots compared to the unmanaged plots. Seedling establishment of two species, Danthonia californica and Potentilla gracilis, was significantly lower with burn treatments. The other five species showed no significant responses to the burn treatments: Carex tumicola, Calochortus tolmiei, Zygadensus venenosus, Balsamorhiza deltoidea, and Agoseris grandilflora. The strongest fire effects were generally in plots that had been burned only once, rather than plots burned more than once. Abundance of litter and vegetation were the factors that were most often related, both positively and negatively, with seedling establishment rates. Based on the results of this investigation, prescribed burning, rather than mowing, is a more viable management option to promote regeneration of native species from seed in upland prairies. However, prescribed burning must be used with caution as it can reduce seedling establishment rates for some species. Sowing seeds in unmanaged sites is an option, but sowing rates need to be high to compensate for the small seedling establishment rates in unmanaged prairies. Close