Search

Search Results

• 1. [Article] History, Current Conditions, and Wetland Restoration at Killin Wetlands Natural Area, Washington County, Oregon

  In September 2014, the Metro Natural Area Program engaged The Wetland Conservancy to develop a scientific assessment of Metro’s 590-acre Killin Wetlands Natural Area. Metro acquired the lands comprising ...

  Citation × Citation Citation Abstract Copy Title: History, Current Conditions, and Wetland Restoration at Killin Wetlands Natural Area, Washington County, Oregon Author: Christy, John A. Year: 2015 In September 2014, the Metro Natural Area Program engaged The Wetland Conservancy to develop a scientific assessment of Metro’s 590-acre Killin Wetlands Natural Area. Metro acquired the lands comprising the KWNA between 2000 and 2012 with funds from two voterapproved open space bond measures. Since 2000, Metro has sought to advance natural area restoration at the site, focusing on the suppression of non-native pasture weeds and planting of native trees and shrubs in higher parts of the floodplain and its edges. Most uplands in Metro ownership have been maintained in agriculture through leased partnerships with local farmers. Metro and its partners have observed the effects of persistent flooding at the site, which began prior to Metro’s acquisition of the property. Most notable has been the decline of the once abundant Geyer willow stand, a prominent and valued feature of the site. In February 2014, Metro convened several key scientists familiar with the wetland, and its underlying Labish soil, to discuss what was known about the Killin Wetlands and possible next steps in advancing restoration there. That discussion focused on the subsidence of organic soils, caused by artificial drainage, and led to the recommendation that a review of regional peat soil wetlands would be an important step in developing an informed plan for preserving and restoring Killin Wetlands. This report presents that review. Title: History, Current Conditions, and Wetland Restoration at Killin Wetlands Natural Area, Washington County, Oregon Author: Christy, John A. Year: 2015 In September 2014, the Metro Natural Area Program engaged The Wetland Conservancy to develop a scientific assessment of Metro’s 590-acre Killin Wetlands Natural Area. Metro acquired the lands comprising the KWNA between 2000 and 2012 with funds from two voterapproved open space bond measures. Since 2000, Metro has sought to advance natural area restoration at the site, focusing on the suppression of non-native pasture weeds and planting of native trees and shrubs in higher parts of the floodplain and its edges. Most uplands in Metro ownership have been maintained in agriculture through leased partnerships with local farmers. Metro and its partners have observed the effects of persistent flooding at the site, which began prior to Metro’s acquisition of the property. Most notable has been the decline of the once abundant Geyer willow stand, a prominent and valued feature of the site. In February 2014, Metro convened several key scientists familiar with the wetland, and its underlying Labish soil, to discuss what was known about the Killin Wetlands and possible next steps in advancing restoration there. That discussion focused on the subsidence of organic soils, caused by artificial drainage, and led to the recommendation that a review of regional peat soil wetlands would be an important step in developing an informed plan for preserving and restoring Killin Wetlands. This report presents that review. Close

• 2. [Article] Riparian Vegetation Assemblages and Associated Landscape Factors Across an Urbanizing Metropolitan Area

  While diverse, native riparian vegetation provides important functions, it remains unclear to what extent these assemblages can persist in urban areas, and under what conditions. We characterized forested ...

  Citation × Citation Citation Abstract Copy Title: Riparian Vegetation Assemblages and Associated Landscape Factors Across an Urbanizing Metropolitan Area Author: Von Behren, Christa, Dietrich, Andrew Evans, Yeakley, J. Alan Year: 2014 While diverse, native riparian vegetation provides important functions, it remains unclear to what extent these assemblages can persist in urban areas, and under what conditions. We characterized forested riparian vegetation communities across an urbanizing metropolitan area and examined their relationships with surrounding land cover. We hypothesized that native and hydrophilic species assemblages would correlate with forest cover in the landscape. For each of 30 sites in the Portland–Vancouver metro area, we recorded vegetation at 1-cm intervals along 3 transects using the line-intercept method. Land cover was characterized at 2 scales: within 500 m of each site and across the entire watershed. Multivariate analyses were used to evaluate relationships between species composition and land cover patterns. A classification tree was created to determine landscape predictors of riparian community type. Results indicated a strong relationship between watershed land cover and vegetation diversity and structural complexity. Our hypothesis of native species association with landscape forest cover in urban riparian areas was supported, but we found no clear relationship between land cover and wetland indicator status. Our results suggest that high watershed forest cover (at least 15%) may enable the persistence of functionally diverse, native riparian vegetation communities in urban landscapes. Keywords: Pacific Northwest, plant diversity, plant ecology, riparian forest, urban ecology, urban watersheds. Title: Riparian Vegetation Assemblages and Associated Landscape Factors Across an Urbanizing Metropolitan Area Author: Von Behren, Christa, Dietrich, Andrew Evans, Yeakley, J. Alan Year: 2014 While diverse, native riparian vegetation provides important functions, it remains unclear to what extent these assemblages can persist in urban areas, and under what conditions. We characterized forested riparian vegetation communities across an urbanizing metropolitan area and examined their relationships with surrounding land cover. We hypothesized that native and hydrophilic species assemblages would correlate with forest cover in the landscape. For each of 30 sites in the Portland–Vancouver metro area, we recorded vegetation at 1-cm intervals along 3 transects using the line-intercept method. Land cover was characterized at 2 scales: within 500 m of each site and across the entire watershed. Multivariate analyses were used to evaluate relationships between species composition and land cover patterns. A classification tree was created to determine landscape predictors of riparian community type. Results indicated a strong relationship between watershed land cover and vegetation diversity and structural complexity. Our hypothesis of native species association with landscape forest cover in urban riparian areas was supported, but we found no clear relationship between land cover and wetland indicator status. Our results suggest that high watershed forest cover (at least 15%) may enable the persistence of functionally diverse, native riparian vegetation communities in urban landscapes. Keywords: Pacific Northwest, plant diversity, plant ecology, riparian forest, urban ecology, urban watersheds. Close

• 3. [Article] Use of Distance Weighted Metrics to Investigate Landscape-Stream Temperature Relationships Across Different Temporal Scales

  Stream ecosystems have experienced significant negative impacts from land use, resource exploitation, and urban development. Statistical models allow researchers to explore the relationships between these ...

  Citation × Citation Citation Abstract Copy Title: Use of Distance Weighted Metrics to Investigate Landscape-Stream Temperature Relationships Across Different Temporal Scales Author: Watson, Eric Craig Year: 2016 Stream ecosystems have experienced significant negative impacts from land use, resource exploitation, and urban development. Statistical models allow researchers to explore the relationships between these landscape variables and stream conditions. Weighting the relevant landscape variables based on hydrologically defined distances offers a potential method of increasing the predictive capacity of statistical models. Using observations from three grouped watersheds in the Portland Metro Area (n=66), I have explored the use of three different weighting schemes against the standard method of taking an areal average. These four different model groups were applied to four stream temperature metrics: mean seven-day moving average maximum daily temperature (Mean7dTmax), number of days exceeding 17.8 °C (Tmax7d>17.8), mean daily range in stream temperature (Range_DTR), and the coefficient of variation in maximum daily temperature (CV_Tmax). These metrics were quantified for the 2011 dry season. The strength of these model groups were also examined at a monthly basis for each of the four months within the dry season. The results demonstrate mixed effectiveness of the weighting schemes, dependent on both the stream temperature metric being predicted as well as the time scale under investigation. Models for Mean7dTmax showed no benefit from the inclusion of distance weighted metrics, while models for Range_DTR consistently improved using distance weighted explanatory variables. Trends in the models for 7dTmax>17.8 and CV_Tmax varied based on temporal scale. Additionally, all model groups demonstrated greater explanatory power in early summer months than in late summer months. Title: Use of Distance Weighted Metrics to Investigate Landscape-Stream Temperature Relationships Across Different Temporal Scales Author: Watson, Eric Craig Year: 2016 Stream ecosystems have experienced significant negative impacts from land use, resource exploitation, and urban development. Statistical models allow researchers to explore the relationships between these landscape variables and stream conditions. Weighting the relevant landscape variables based on hydrologically defined distances offers a potential method of increasing the predictive capacity of statistical models. Using observations from three grouped watersheds in the Portland Metro Area (n=66), I have explored the use of three different weighting schemes against the standard method of taking an areal average. These four different model groups were applied to four stream temperature metrics: mean seven-day moving average maximum daily temperature (Mean7dTmax), number of days exceeding 17.8 °C (Tmax7d>17.8), mean daily range in stream temperature (Range_DTR), and the coefficient of variation in maximum daily temperature (CV_Tmax). These metrics were quantified for the 2011 dry season. The strength of these model groups were also examined at a monthly basis for each of the four months within the dry season. The results demonstrate mixed effectiveness of the weighting schemes, dependent on both the stream temperature metric being predicted as well as the time scale under investigation. Models for Mean7dTmax showed no benefit from the inclusion of distance weighted metrics, while models for Range_DTR consistently improved using distance weighted explanatory variables. Trends in the models for 7dTmax>17.8 and CV_Tmax varied based on temporal scale. Additionally, all model groups demonstrated greater explanatory power in early summer months than in late summer months. Close

• 4. [Article] Historical and Existing Vascular and Bryophyte Flora, Former Blue Heron Paper Mill, Willamette Falls, Oregon City, Oregon

  Willamette Falls has long been a focus of botanical interest, but industrial development at the site has limited public access for over a century. The closure of the Blue Heron paper mill on the south ...

  Citation × Citation Citation Abstract Copy Title: Historical and Existing Vascular and Bryophyte Flora, Former Blue Heron Paper Mill, Willamette Falls, Oregon City, Oregon Author: Christy, John A., Gaddis, Philip Year: 2015 Willamette Falls has long been a focus of botanical interest, but industrial development at the site has limited public access for over a century. The closure of the Blue Heron paper mill on the south bank of the river, and proposed redevelopment of the site, has given planners an opportunity to revisit this part of the falls and identify its current flora. As part of the preconstruction planning process for public access to the falls, Metro contracted John Christy to document the historical and existing vascular flora on the site, and Philip Gaddis joined us to document the bryophyte flora. For millennia, the falls has been a magnet for fishing, settlement, and more recent industrial development. Photographs by Carleton Watkins show that the south bank of the river at Willamette Falls had been modified for industrial uses as early as 1867. Infrastructure included dams and spillways to create a boat basin, and millraces to power a sawmill, gristmill, and woolen mill. Later, paper mills and electrical generating stations were built on both sides of the falls. These activities concentrated at the falls have impacted all native habitat except vertical cliff faces on basalt outcrops along the river. Significant portions of the shoreline at the Blue Heron site have been modified by fill. Remaining habitat in natural or semi-natural condition includes areas hydrated by tidal action of the Willamette River, areas of seasonal or perennial seepage below spillways and the old grinders, and basalt outcrops with varying exposures. The basalt outcrops are a relic of the Bretz or Missoula Floods (Allen et al. 1986), and exposures along this part of the Willamette River provide outlier habitat for both mesic and xeric species more common in the Columbia River Gorge (Detling 1958). Willamette Falls has a similar history to that of Niagara Falls in terms of industrial development, presence of a rock substrate supporting disjunct populations of rare plants, and botanical exploration that occurred primarily between 1885 and 1915 (Eckel 2013). Title: Historical and Existing Vascular and Bryophyte Flora, Former Blue Heron Paper Mill, Willamette Falls, Oregon City, Oregon Author: Christy, John A., Gaddis, Philip Year: 2015 Willamette Falls has long been a focus of botanical interest, but industrial development at the site has limited public access for over a century. The closure of the Blue Heron paper mill on the south bank of the river, and proposed redevelopment of the site, has given planners an opportunity to revisit this part of the falls and identify its current flora. As part of the preconstruction planning process for public access to the falls, Metro contracted John Christy to document the historical and existing vascular flora on the site, and Philip Gaddis joined us to document the bryophyte flora. For millennia, the falls has been a magnet for fishing, settlement, and more recent industrial development. Photographs by Carleton Watkins show that the south bank of the river at Willamette Falls had been modified for industrial uses as early as 1867. Infrastructure included dams and spillways to create a boat basin, and millraces to power a sawmill, gristmill, and woolen mill. Later, paper mills and electrical generating stations were built on both sides of the falls. These activities concentrated at the falls have impacted all native habitat except vertical cliff faces on basalt outcrops along the river. Significant portions of the shoreline at the Blue Heron site have been modified by fill. Remaining habitat in natural or semi-natural condition includes areas hydrated by tidal action of the Willamette River, areas of seasonal or perennial seepage below spillways and the old grinders, and basalt outcrops with varying exposures. The basalt outcrops are a relic of the Bretz or Missoula Floods (Allen et al. 1986), and exposures along this part of the Willamette River provide outlier habitat for both mesic and xeric species more common in the Columbia River Gorge (Detling 1958). Willamette Falls has a similar history to that of Niagara Falls in terms of industrial development, presence of a rock substrate supporting disjunct populations of rare plants, and botanical exploration that occurred primarily between 1885 and 1915 (Eckel 2013). Close

• 5. [Article] Relationships Between Environmental Governance and Water Quality in a Growing Metropolitan Area of the Pacific Northwest, USA

  We investigate relationships between environmental governance and water quality in two adjacent growing metropolitan areas in the western US. While the Portland, Oregon and Vancouver, Washington metro ...

  Citation × Citation Citation Abstract Copy Title: Relationships Between Environmental Governance and Water Quality in a Growing Metropolitan Area of the Pacific Northwest, USA Author: Chang, Heejun, Thiers, Paul R., Netusil, Noelwah R., Yeakley, J. Alan, Rollwagen-Bollens, Gretchen, Bollens, Steve, Singh, Sonia Year: 2014 We investigate relationships between environmental governance and water quality in two adjacent growing metropolitan areas in the western US. While the Portland, Oregon and Vancouver, Washington metro areas share many common biophysical characteristics, they have different land development histories and water governance structures, providing a unique opportunity for examining how differences in governance might affect environmental quality. We conceptualize possible linkages in which water quality influences governance directly, using monitoring efforts as a metric, and indirectly by using the change in the sale price of single-family residential properties. Governance may then influence water quality directly through riparian restoration resulting from monitoring results and indirectly through land use policy.We investigate evidence to substantiate these linkages. Our results showed that changes in monitoring regimes and land development patterns differed in response to differences in growth management policy and environmental governance systems. Our results also showed similarities in environmental quality responses to varying governance systems. For example, we found that sales prices responded positively to improved water quality (e.g., increases in DO and reductions in bacteria counts) in both cities. Furthermore, riparian restoration efforts improved over time for both cities, indicating the positive effect of governance on this land-based resource that may result in improved water quality. However, as of yet, there were no substantial differences across study areas in water temperature over time, despite an expansion of these urban areas of more than 20%over 24 years. The mechanisms by which water quality was maintained was similar in the sense that both cities benefited from riparian restoration, but different in the sense that Portland benefited indirectly from land use policy. A combination of long-term legacy effects of land development, and a relatively short history of riparian restoration in both the Portland and Vancouver regions, may have masked any subtle differences between study areas. An alternative explanation is that both cities exhibited combinations of positive indirect and direct water quality governance that resulted in maintenance of water quality in the face of increased urban growth. These findings suggest that a much longer-term water quality monitoring effort is needed to identify the effectiveness of alternative land development and water governance policies Title: Relationships Between Environmental Governance and Water Quality in a Growing Metropolitan Area of the Pacific Northwest, USA Author: Chang, Heejun, Thiers, Paul R., Netusil, Noelwah R., Yeakley, J. Alan, Rollwagen-Bollens, Gretchen, Bollens, Steve, Singh, Sonia Year: 2014 We investigate relationships between environmental governance and water quality in two adjacent growing metropolitan areas in the western US. While the Portland, Oregon and Vancouver, Washington metro areas share many common biophysical characteristics, they have different land development histories and water governance structures, providing a unique opportunity for examining how differences in governance might affect environmental quality. We conceptualize possible linkages in which water quality influences governance directly, using monitoring efforts as a metric, and indirectly by using the change in the sale price of single-family residential properties. Governance may then influence water quality directly through riparian restoration resulting from monitoring results and indirectly through land use policy.We investigate evidence to substantiate these linkages. Our results showed that changes in monitoring regimes and land development patterns differed in response to differences in growth management policy and environmental governance systems. Our results also showed similarities in environmental quality responses to varying governance systems. For example, we found that sales prices responded positively to improved water quality (e.g., increases in DO and reductions in bacteria counts) in both cities. Furthermore, riparian restoration efforts improved over time for both cities, indicating the positive effect of governance on this land-based resource that may result in improved water quality. However, as of yet, there were no substantial differences across study areas in water temperature over time, despite an expansion of these urban areas of more than 20%over 24 years. The mechanisms by which water quality was maintained was similar in the sense that both cities benefited from riparian restoration, but different in the sense that Portland benefited indirectly from land use policy. A combination of long-term legacy effects of land development, and a relatively short history of riparian restoration in both the Portland and Vancouver regions, may have masked any subtle differences between study areas. An alternative explanation is that both cities exhibited combinations of positive indirect and direct water quality governance that resulted in maintenance of water quality in the face of increased urban growth. These findings suggest that a much longer-term water quality monitoring effort is needed to identify the effectiveness of alternative land development and water governance policies Close