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• 1. [Article] The Response of Zooplankton Communities in Montane Lakes of Different Fish Stocking Histories to Atmospheric Nitrogen Deposition Simulations

  Freshwater ecosystems are subject to a wide variety of stressors, which can have complex interactions and result in ecological surprises. Non-native fish introductions have drastically reduced the number ...

  Citation × Citation Citation Abstract Copy Title: The Response of Zooplankton Communities in Montane Lakes of Different Fish Stocking Histories to Atmospheric Nitrogen Deposition Simulations Author: Brittain, Jeffrey Thomas Year: 2015 Freshwater ecosystems are subject to a wide variety of stressors, which can have complex interactions and result in ecological surprises. Non-native fish introductions have drastically reduced the number of naturally fishless lakes and have resulted in cascading food web repercussions in aquatic and terrestrial habitats. Additional anthropogenic influences that result from increases in global airborne emissions also threaten wildlife habitat. Atmospheric nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of wilderness ecosystems. Planktonic communities have shown declines in response to predation and shifts in composition as a result of nutrient inputs and acidification, both of which are potential fates of nitrogen deposition. This study identified the response of zooplankton communities from two lakes (fish present vs. absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance event in mesocosms. The experiment used a 2 x 2 factorial design with acid and nitrogen treatments. Treatments resulted in significantly elevated nitrogen and decreased pH conditions from control mesocosms over 42 days, indicating that the treatment effects were achieved. Results indicate that zooplankton communities from lakes with different food web structure respond differently to the singular effects of acid and nitrogen addition. Surprisingly, the interaction of the two stressors was related to increases in community metrics (e.g., abundance, biomass, body size, richness, and Shannon-Weiner diversity) for both lake types. This work can aid management decisions as agencies look to restore more aquatic montane habitats to their historic fishless states, and assess their abilities to recover and afford resistance to atmospheric pollution. Title: The Response of Zooplankton Communities in Montane Lakes of Different Fish Stocking Histories to Atmospheric Nitrogen Deposition Simulations Author: Brittain, Jeffrey Thomas Year: 2015 Freshwater ecosystems are subject to a wide variety of stressors, which can have complex interactions and result in ecological surprises. Non-native fish introductions have drastically reduced the number of naturally fishless lakes and have resulted in cascading food web repercussions in aquatic and terrestrial habitats. Additional anthropogenic influences that result from increases in global airborne emissions also threaten wildlife habitat. Atmospheric nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of wilderness ecosystems. Planktonic communities have shown declines in response to predation and shifts in composition as a result of nutrient inputs and acidification, both of which are potential fates of nitrogen deposition. This study identified the response of zooplankton communities from two lakes (fish present vs. absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance event in mesocosms. The experiment used a 2 x 2 factorial design with acid and nitrogen treatments. Treatments resulted in significantly elevated nitrogen and decreased pH conditions from control mesocosms over 42 days, indicating that the treatment effects were achieved. Results indicate that zooplankton communities from lakes with different food web structure respond differently to the singular effects of acid and nitrogen addition. Surprisingly, the interaction of the two stressors was related to increases in community metrics (e.g., abundance, biomass, body size, richness, and Shannon-Weiner diversity) for both lake types. This work can aid management decisions as agencies look to restore more aquatic montane habitats to their historic fishless states, and assess their abilities to recover and afford resistance to atmospheric pollution. Close

• 2. [Article] Community level impacts associated with the invasion of English ivy (Hedera spp.) in Forest Park: a look at the impacts of ivy on community composition and soil moisture.

  Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species ...

  Citation × Citation Citation Abstract Copy Title: Community level impacts associated with the invasion of English ivy (Hedera spp.) in Forest Park: a look at the impacts of ivy on community composition and soil moisture. Author: Copp, Sara Rose Year: 2014 Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species to exploit limiting resources making the community prone to invasion. In the Pacific Northwest, urban forests characterized with limited light and seasonally limited soil moisture are being dominated by nonnative English ivy (Hedera spp). Three observational studies were conducted in the Southern end of Forest Park within the Balch Creek Subwatershed in Portland, Oregon in order to understand 1) how English ivy changes over three growing seasons, 2) how the native understory composition responds to English ivy, 3) if the dominance of English ivy reduces soil moisture to neighboring plants, 4) how English ivy and two co-occurring native herbs (Hydrophyllum tenuipes and Vancouveria hexandra) physiologically respond to seasonal changes in soil moisture. Percent cover of the understory community was collected in both 2010 and 2013 growing seasons in 54 plots in order to understand the change in cover over time. Community response and the relationship with soil moisture was analyzed using percent cover of the understory community and associated environmental variables including soil moisture collected in 128 plots during the 2013 field season. Finally, 15 plots with co-occurring Hedera spp, H. tenuipes and V. hexandra were sampled for stomatal conductance, leaf water potential, and associated environmental variables. Results show ivy cover increases on average 14% between 2010 and 2013 while native understory cover increased on average < 1%. Once ivy forms dense cover over 44% there is a reduction of native richness, diversity and herb cover while also an increase in available soil moisture and deciduous canopy cover. There were disparate impacts to different functional groups and between species. As functional group, the herbaceous community was the most impacted by ivy invasion. The shrubs and fern community had a variable response to ivy invasion. Many of the fern and shrub species least impacted by ivy also had associations with high soil moisture and deciduous canopy cover. Finally, data suggests that ivy does not take advantage of seasonally limiting soil moisture to invade the understory community. This study indicates that English ivy is both efficient at water use and may have the ability to obtain water from distant locations throughout the forest. Once established, ivy has the ability to alter the community composition. Ivy removal and habitat restoration are essential in order to maintain and enhance biodiversity in Forest Park. Title: Community level impacts associated with the invasion of English ivy (Hedera spp.) in Forest Park: a look at the impacts of ivy on community composition and soil moisture. Author: Copp, Sara Rose Year: 2014 Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species to exploit limiting resources making the community prone to invasion. In the Pacific Northwest, urban forests characterized with limited light and seasonally limited soil moisture are being dominated by nonnative English ivy (Hedera spp). Three observational studies were conducted in the Southern end of Forest Park within the Balch Creek Subwatershed in Portland, Oregon in order to understand 1) how English ivy changes over three growing seasons, 2) how the native understory composition responds to English ivy, 3) if the dominance of English ivy reduces soil moisture to neighboring plants, 4) how English ivy and two co-occurring native herbs (Hydrophyllum tenuipes and Vancouveria hexandra) physiologically respond to seasonal changes in soil moisture. Percent cover of the understory community was collected in both 2010 and 2013 growing seasons in 54 plots in order to understand the change in cover over time. Community response and the relationship with soil moisture was analyzed using percent cover of the understory community and associated environmental variables including soil moisture collected in 128 plots during the 2013 field season. Finally, 15 plots with co-occurring Hedera spp, H. tenuipes and V. hexandra were sampled for stomatal conductance, leaf water potential, and associated environmental variables. Results show ivy cover increases on average 14% between 2010 and 2013 while native understory cover increased on average < 1%. Once ivy forms dense cover over 44% there is a reduction of native richness, diversity and herb cover while also an increase in available soil moisture and deciduous canopy cover. There were disparate impacts to different functional groups and between species. As functional group, the herbaceous community was the most impacted by ivy invasion. The shrubs and fern community had a variable response to ivy invasion. Many of the fern and shrub species least impacted by ivy also had associations with high soil moisture and deciduous canopy cover. Finally, data suggests that ivy does not take advantage of seasonally limiting soil moisture to invade the understory community. This study indicates that English ivy is both efficient at water use and may have the ability to obtain water from distant locations throughout the forest. Once established, ivy has the ability to alter the community composition. Ivy removal and habitat restoration are essential in order to maintain and enhance biodiversity in Forest Park. Close

• 3. [Article] Green Roofs and Urban Biodiversity: Their Role as Invertebrate Habitat and the Effect of Design on Beetle Community

  With over half the world's population now living in cities, urban areas represent one of earth's few ecosystems that are increasing in extent, and are sites of altered biogeochemical cycles, habitat fragmentation, ...

  Citation × Citation Citation Abstract Copy Title: Green Roofs and Urban Biodiversity: Their Role as Invertebrate Habitat and the Effect of Design on Beetle Community Author: Gonsalves, Sydney Marie Year: 2016 With over half the world's population now living in cities, urban areas represent one of earth's few ecosystems that are increasing in extent, and are sites of altered biogeochemical cycles, habitat fragmentation, and changes in biodiversity. However, urban green spaces, including green roofs, can also provide important pools of biodiversity and contribute to regional gamma diversity, while novel species assemblages can enhance some ecosystem services. Green roofs may also mitigate species loss in urban areas and have been shown to support a surprising diversity of invertebrates, including rare and endangered species. In the first part of this study I reviewed the literature on urban invertebrate communities and diversity to better understand the role of green roofs in providing habitat in the context of the larger urban mosaic. My review concluded that, while other factors such as surrounding land use and connectivity are also important to specific invertebrate taxa, local habitat variables contribute substantially to the structure and diversity of urban invertebrate communities. The importance of local habitat variables in urban green spaces and strong support for the habitat complexity hypothesis in a number of other ecosystems has led to proposals that "biodiverse" roofs--those intentionally designed with varied substrate depth, greater plant diversity, or added elements such as logs or stones--would support greater invertebrate diversity, but there is currently limited peer reviewed data to support this. In order to address the habitat complexity hypothesis in the context of green roofs, in the second part of this study I surveyed three roofs designed primarily for stormwater management, three biodiverse roofs, and five ground-level green spaces, from March until September of 2014 in the Portland metropolitan area. Beetles (Coleoptera) were sampled bi-weekly as representatives of total species diversity. Biodiverse roofs had greater richness, abundance, and diversity of beetle species compared to stormwater roofs, but were not more diverse than ground sites. Both biodiverse roofs and ground sites had approximately 20% native beetle species while stormwater roofs had only 5%. Functional diversity was also higher on biodiverse roofs with an average of seven trophic groups represented, while stormwater roofs averaged only three. Ground sites, biodiverse roofs, and stormwater roofs each grouped distinctively in terms of beetle community composition and biodiverse roof communities were found to be positively correlated with roof age, percent plant cover, average plant height, and plant species richness. These results support the findings of previous studies on the importance of local variables in structuring urban invertebrate communities and suggest that biodiverse design can reliably increase greenroof diversity, with the caution that they remain no replacement for ground level conservation. Title: Green Roofs and Urban Biodiversity: Their Role as Invertebrate Habitat and the Effect of Design on Beetle Community Author: Gonsalves, Sydney Marie Year: 2016 With over half the world's population now living in cities, urban areas represent one of earth's few ecosystems that are increasing in extent, and are sites of altered biogeochemical cycles, habitat fragmentation, and changes in biodiversity. However, urban green spaces, including green roofs, can also provide important pools of biodiversity and contribute to regional gamma diversity, while novel species assemblages can enhance some ecosystem services. Green roofs may also mitigate species loss in urban areas and have been shown to support a surprising diversity of invertebrates, including rare and endangered species. In the first part of this study I reviewed the literature on urban invertebrate communities and diversity to better understand the role of green roofs in providing habitat in the context of the larger urban mosaic. My review concluded that, while other factors such as surrounding land use and connectivity are also important to specific invertebrate taxa, local habitat variables contribute substantially to the structure and diversity of urban invertebrate communities. The importance of local habitat variables in urban green spaces and strong support for the habitat complexity hypothesis in a number of other ecosystems has led to proposals that "biodiverse" roofs--those intentionally designed with varied substrate depth, greater plant diversity, or added elements such as logs or stones--would support greater invertebrate diversity, but there is currently limited peer reviewed data to support this. In order to address the habitat complexity hypothesis in the context of green roofs, in the second part of this study I surveyed three roofs designed primarily for stormwater management, three biodiverse roofs, and five ground-level green spaces, from March until September of 2014 in the Portland metropolitan area. Beetles (Coleoptera) were sampled bi-weekly as representatives of total species diversity. Biodiverse roofs had greater richness, abundance, and diversity of beetle species compared to stormwater roofs, but were not more diverse than ground sites. Both biodiverse roofs and ground sites had approximately 20% native beetle species while stormwater roofs had only 5%. Functional diversity was also higher on biodiverse roofs with an average of seven trophic groups represented, while stormwater roofs averaged only three. Ground sites, biodiverse roofs, and stormwater roofs each grouped distinctively in terms of beetle community composition and biodiverse roof communities were found to be positively correlated with roof age, percent plant cover, average plant height, and plant species richness. These results support the findings of previous studies on the importance of local variables in structuring urban invertebrate communities and suggest that biodiverse design can reliably increase greenroof diversity, with the caution that they remain no replacement for ground level conservation. Close

• 4. [Article] Plant Nitrogen Concentration and Isotopic Composition in Residential Lawns Across Seven US Cities

  Human drivers are often proposed to be stronger than biophysical drivers in influencing ecosystem structure and function in highly urbanized areas. In residential land cover, private yards are influenced ...

  Citation × Citation Citation Abstract Copy Title: Plant Nitrogen Concentration and Isotopic Composition in Residential Lawns Across Seven US Cities Author: Trammell, Tara, Pataki, Diane E., Cavender-Bares, Jeannine, Groffman, Peter M., Hall, Sharon J. Year: 2016 Human drivers are often proposed to be stronger than biophysical drivers in influencing ecosystem structure and function in highly urbanized areas. In residential land cover, private yards are influenced by individual homeowner preferences and actions while also experiencing large-scale human and biophysical drivers. We studied plant nitrogen (%N) and N stable isotopic composition (δ15N) in residential yards and paired native ecosystems in seven cities across the US that span major ecological biomes and climatic regions: Baltimore, Boston, Los Angeles, Miami, Minneapolis-St. Paul, Phoenix, and Salt Lake City. We found that residential lawns in three cities had enriched plant δ15N (P < 0.03) and in six cities higher plant N (%) relative to the associated native ecosystems (P < 0.05). Plant δ15N was progressively depleted across a gradient of urban density classes in Baltimore and Boston (P < 0.05). Lawn fertilization was associated with depleted plant δ15N in Boston and Los Angeles (P < 0.05), and organic fertilizer additions were associated with enriched plant δ15N in Los Angeles and Salt Lake City (P < 0.04). Plant δ15N was significantly enriched as a function of housing age in Baltimore (r2 = 0.27, P < 0.02), Boston (r2 = 0.27, P < 0.01), and Los Angeles (r2 = 0.34, P < 0.01). These patterns in plant δ15N and plant N (%) across these cities suggests that N sources to lawns, as well as greater rates of N cycling combined with subsequent N losses, may be important drivers of plant N dynamics in lawn ecosystems at the national scale. Title: Plant Nitrogen Concentration and Isotopic Composition in Residential Lawns Across Seven US Cities Author: Trammell, Tara, Pataki, Diane E., Cavender-Bares, Jeannine, Groffman, Peter M., Hall, Sharon J. Year: 2016 Human drivers are often proposed to be stronger than biophysical drivers in influencing ecosystem structure and function in highly urbanized areas. In residential land cover, private yards are influenced by individual homeowner preferences and actions while also experiencing large-scale human and biophysical drivers. We studied plant nitrogen (%N) and N stable isotopic composition (δ15N) in residential yards and paired native ecosystems in seven cities across the US that span major ecological biomes and climatic regions: Baltimore, Boston, Los Angeles, Miami, Minneapolis-St. Paul, Phoenix, and Salt Lake City. We found that residential lawns in three cities had enriched plant δ15N (P < 0.03) and in six cities higher plant N (%) relative to the associated native ecosystems (P < 0.05). Plant δ15N was progressively depleted across a gradient of urban density classes in Baltimore and Boston (P < 0.05). Lawn fertilization was associated with depleted plant δ15N in Boston and Los Angeles (P < 0.05), and organic fertilizer additions were associated with enriched plant δ15N in Los Angeles and Salt Lake City (P < 0.04). Plant δ15N was significantly enriched as a function of housing age in Baltimore (r2 = 0.27, P < 0.02), Boston (r2 = 0.27, P < 0.01), and Los Angeles (r2 = 0.34, P < 0.01). These patterns in plant δ15N and plant N (%) across these cities suggests that N sources to lawns, as well as greater rates of N cycling combined with subsequent N losses, may be important drivers of plant N dynamics in lawn ecosystems at the national scale. Close

• 5. [Article] Spatial and Temporal Variability of Contaminants Within Estuarine Sediments and Native Olympia Oysters: A Contrast Between a Developed and an Undeveloped Estuary

  Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from ...

  Citation × Citation Citation Abstract Copy Title: Spatial and Temporal Variability of Contaminants Within Estuarine Sediments and Native Olympia Oysters: A Contrast Between a Developed and an Undeveloped Estuary Author: Granek, Elise F., Conn, Katherine E., Nilsen, Elena B., Pillsbury, Lori, Strecker, Angela L., Rumrill, Steven S., Fish, William Year: 2016 Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from industrial, municipal, and urban lands, accidental spills, and atmospheric deposition. The diversity of potential sources contributes to the likelihood of contaminated marine waters and sediments and increases the probability of uptake by marine organisms. Despite widespread recognition of direct and indirect pathways for contaminant deposition and organismal exposure in coastal systems, spatial and temporal variability in contaminant composition, deposition, and uptake patterns are still poorly known. We investigated these patterns for a suite of persistent legacy contaminants including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chemicals of emerging concern including pharmaceuticals within two Oregon coastal estuaries (Coos and Netarts Bays). In the more urbanized Coos Bay, native Olympia oyster (Ostrea lurida) tissue had approximately twice the number of PCB congeners at over seven times the total concentration, yet fewer PBDEs at one-tenth the concentration as compared to the more rural Netarts Bay. Different pharmaceutical suites were detected during each sampling season. Variability in contaminant types and concentrations across seasons and between species and media (organisms versus sediment) indicates the limitation of using indicator species and/or sampling annually to determine contaminant loads at a site or for specific species. The results indicate the prevalence of legacy contaminants and CECs in relatively undeveloped coastal environments highlighting the need to improve policy and management actions to reduce contaminant releases into estuarine and marine waters and to deal with legacy compounds that remain long after prohibition of use. Our results point to the need for better understanding of the ecological and human health risks of exposure to the diverse cocktail of pollutants and harmful compounds that will continue to leach from estuarine sediments over time. Title: Spatial and Temporal Variability of Contaminants Within Estuarine Sediments and Native Olympia Oysters: A Contrast Between a Developed and an Undeveloped Estuary Author: Granek, Elise F., Conn, Katherine E., Nilsen, Elena B., Pillsbury, Lori, Strecker, Angela L., Rumrill, Steven S., Fish, William Year: 2016 Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from industrial, municipal, and urban lands, accidental spills, and atmospheric deposition. The diversity of potential sources contributes to the likelihood of contaminated marine waters and sediments and increases the probability of uptake by marine organisms. Despite widespread recognition of direct and indirect pathways for contaminant deposition and organismal exposure in coastal systems, spatial and temporal variability in contaminant composition, deposition, and uptake patterns are still poorly known. We investigated these patterns for a suite of persistent legacy contaminants including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chemicals of emerging concern including pharmaceuticals within two Oregon coastal estuaries (Coos and Netarts Bays). In the more urbanized Coos Bay, native Olympia oyster (Ostrea lurida) tissue had approximately twice the number of PCB congeners at over seven times the total concentration, yet fewer PBDEs at one-tenth the concentration as compared to the more rural Netarts Bay. Different pharmaceutical suites were detected during each sampling season. Variability in contaminant types and concentrations across seasons and between species and media (organisms versus sediment) indicates the limitation of using indicator species and/or sampling annually to determine contaminant loads at a site or for specific species. The results indicate the prevalence of legacy contaminants and CECs in relatively undeveloped coastal environments highlighting the need to improve policy and management actions to reduce contaminant releases into estuarine and marine waters and to deal with legacy compounds that remain long after prohibition of use. Our results point to the need for better understanding of the ecological and human health risks of exposure to the diverse cocktail of pollutants and harmful compounds that will continue to leach from estuarine sediments over time. Close

• 6. [Article] Convergence of Microclimate in Residential Landscapes Across Diverse Cities in the United States

  Context The urban heat island (UHI) is a welldocumented pattern of warming in cities relative to rural areas. Most UHI research utilizes remote sensing methods at large scales, or climate sensors in single ...

  Citation × Citation Citation Abstract Copy Title: Convergence of Microclimate in Residential Landscapes Across Diverse Cities in the United States Author: Hall, Sharon J., Learned, J, Ruddell, Benjamin, Larson, Kelli L., Cavender-Bares, Jeannine, Bettez, Neil D., Groffman, Peter M., Grove, J. Morgan, Heffernan, James B., Hobbie, Sarah E., Larson, Kristen, Morse, Jennifer L., Neill, Christopher, Nelson, Kristen C., O'Neil-Dunne, Jarlath, Ogden, Laura A., Pataki, Diane E., Pearse, William D., Polsky, Colin, Chowdhury, Rinku Roy, Steele, Meredith K., Trammell, Tara Year: 2015 Context The urban heat island (UHI) is a welldocumented pattern of warming in cities relative to rural areas. Most UHI research utilizes remote sensing methods at large scales, or climate sensors in single cities surrounded by standardized land cover. Relatively few studies have explored continental-scale climatic patterns within common urban microenvironments such as residential landscapes that may affect human comfort. Objectives We tested the urban homogenization hypothesis which states that structure and function in cities exhibit ecological ‘‘sameness’’ across diverse regions relative to the native ecosystems they replaced. Methods We deployed portable micrometeorological sensors to compare air temperature and humidity in residential yards and native landscapes across six U.S. cities that span a range of climates (Phoenix, AZ; Los Angeles, CA; Minneapolis-St. Paul, MN; Boston, MA; Baltimore, MD; and Miami, FL). Results Microclimate in residential ecosystems was more similar among cities than among native ecosystems, particularly during the calm morning hours. Maximum regional actual evapotranspiration (AET) was related to the morning residential microclimate effect. Residential yards in cities with maximum AET \50–65 cm/year (Phoenix and Los Angeles) were generally cooler and more humid than nearby native shrublands during summer mornings, while yards in cities above this threshold were generally warmer (Baltimore and Miami) and drier (Miami) than native forests. On average, temperature and absolute humidity were *6 % less variable among residential ecosystems than among native ecosystems from diverse regions. Conclusions These data suggest that common residential land cover and structural characteristics lead to microclimatic convergence across diverse regions at the continental scale. Title: Convergence of Microclimate in Residential Landscapes Across Diverse Cities in the United States Author: Hall, Sharon J., Learned, J, Ruddell, Benjamin, Larson, Kelli L., Cavender-Bares, Jeannine, Bettez, Neil D., Groffman, Peter M., Grove, J. Morgan, Heffernan, James B., Hobbie, Sarah E., Larson, Kristen, Morse, Jennifer L., Neill, Christopher, Nelson, Kristen C., O'Neil-Dunne, Jarlath, Ogden, Laura A., Pataki, Diane E., Pearse, William D., Polsky, Colin, Chowdhury, Rinku Roy, Steele, Meredith K., Trammell, Tara Year: 2015 Context The urban heat island (UHI) is a welldocumented pattern of warming in cities relative to rural areas. Most UHI research utilizes remote sensing methods at large scales, or climate sensors in single cities surrounded by standardized land cover. Relatively few studies have explored continental-scale climatic patterns within common urban microenvironments such as residential landscapes that may affect human comfort. Objectives We tested the urban homogenization hypothesis which states that structure and function in cities exhibit ecological ‘‘sameness’’ across diverse regions relative to the native ecosystems they replaced. Methods We deployed portable micrometeorological sensors to compare air temperature and humidity in residential yards and native landscapes across six U.S. cities that span a range of climates (Phoenix, AZ; Los Angeles, CA; Minneapolis-St. Paul, MN; Boston, MA; Baltimore, MD; and Miami, FL). Results Microclimate in residential ecosystems was more similar among cities than among native ecosystems, particularly during the calm morning hours. Maximum regional actual evapotranspiration (AET) was related to the morning residential microclimate effect. Residential yards in cities with maximum AET \50–65 cm/year (Phoenix and Los Angeles) were generally cooler and more humid than nearby native shrublands during summer mornings, while yards in cities above this threshold were generally warmer (Baltimore and Miami) and drier (Miami) than native forests. On average, temperature and absolute humidity were *6 % less variable among residential ecosystems than among native ecosystems from diverse regions. Conclusions These data suggest that common residential land cover and structural characteristics lead to microclimatic convergence across diverse regions at the continental scale. Close

• 7. [Article] Riparian Wetland Plant Response to Livestock Exclusion in the Lower Columbia River Basin

  The purpose of this study was to examine the characteristics of riparian plant communities along a gradient of livestock exclusion in the Lower Columbia River Basin (LCRB) located in the Pacific Northwest ...

  Citation × Citation Citation Abstract Copy Title: Riparian Wetland Plant Response to Livestock Exclusion in the Lower Columbia River Basin Author: Kidd, S. A., Yeakley, J. Alan Year: 2015 The purpose of this study was to examine the characteristics of riparian plant communities along a gradient of livestock exclusion in the Lower Columbia River Basin (LCRB) located in the Pacific Northwest region of the United States. Livestock exclusion from riparian wetlands is a common passive restoration technique. Few studies, however, have focused on the effects of livestock grazing or the exclusion of livestock grazing on these ecosystems. Vegetation community composition was examined in two passive restoration sites, three and 13 years since livestock exclusion, and in a reference site with continued livestock grazing. We hypothesized native plant species richness would be lower in the excluded wetlands than in the grazed wetland due to the competitive exclusion from an increase in non-native plant dominance in the absence of grazing. The grazed wetland had significantly (P < 0.02) greater mean total species richness (23.3 ± 1.6; mean ± 1 standard error), native (10.2 ± 0.5), and non-native (12 ± 1.5) species richness than both the excluded wetlands. Mean total species richness did not differ significantly (P = 0.088) between the three-year (12 ± 1.4) and 13-year (5.5 ± 2.3) excluded wetlands. Mean native and non-native species richness also did not differ significantly (native P = 0.088. non-native P = 0.064) between the three-year (native 6.3 ± 0.6, non-native 5 ± 2.3) and 13-year (native 2.8 ± 1.3, non-native 2.7 ± 1.1) excluded wetlands. However, native species abundance as indicated by percent cover was significantly (P < 0.02) lower in the 13-year excluded wetland (4.2 ± 2.0%) than both the three-year excluded (51.5 ± 3.9%) and grazed (23.2 ± 3.3%) wetlands. The invasive grass, Phalaris arundinacea (reed canarygrass), was found to be the dominant vegetation cover in all three wetlands, with average relative cover ranging from 95.2 ± 2.0% at the 13-year exclusion site to 52.8 ± 4.1% at the grazing site, and 43.0 ± 4.0% cover at the three-year exclusion site. These observations suggest that livestock exclusion alone may be an ineffective strategy for restoring riparian plant communities in regions such as LCRB where invasive species like reed canarygrass are abundant. More effective management alternatives might include short-term livestock exclusion and reintroduced targeted grazing to both reduce livestock impacts and control reed canarygrass dominance. Title: Riparian Wetland Plant Response to Livestock Exclusion in the Lower Columbia River Basin Author: Kidd, S. A., Yeakley, J. Alan Year: 2015 The purpose of this study was to examine the characteristics of riparian plant communities along a gradient of livestock exclusion in the Lower Columbia River Basin (LCRB) located in the Pacific Northwest region of the United States. Livestock exclusion from riparian wetlands is a common passive restoration technique. Few studies, however, have focused on the effects of livestock grazing or the exclusion of livestock grazing on these ecosystems. Vegetation community composition was examined in two passive restoration sites, three and 13 years since livestock exclusion, and in a reference site with continued livestock grazing. We hypothesized native plant species richness would be lower in the excluded wetlands than in the grazed wetland due to the competitive exclusion from an increase in non-native plant dominance in the absence of grazing. The grazed wetland had significantly (P < 0.02) greater mean total species richness (23.3 ± 1.6; mean ± 1 standard error), native (10.2 ± 0.5), and non-native (12 ± 1.5) species richness than both the excluded wetlands. Mean total species richness did not differ significantly (P = 0.088) between the three-year (12 ± 1.4) and 13-year (5.5 ± 2.3) excluded wetlands. Mean native and non-native species richness also did not differ significantly (native P = 0.088. non-native P = 0.064) between the three-year (native 6.3 ± 0.6, non-native 5 ± 2.3) and 13-year (native 2.8 ± 1.3, non-native 2.7 ± 1.1) excluded wetlands. However, native species abundance as indicated by percent cover was significantly (P < 0.02) lower in the 13-year excluded wetland (4.2 ± 2.0%) than both the three-year excluded (51.5 ± 3.9%) and grazed (23.2 ± 3.3%) wetlands. The invasive grass, Phalaris arundinacea (reed canarygrass), was found to be the dominant vegetation cover in all three wetlands, with average relative cover ranging from 95.2 ± 2.0% at the 13-year exclusion site to 52.8 ± 4.1% at the grazing site, and 43.0 ± 4.0% cover at the three-year exclusion site. These observations suggest that livestock exclusion alone may be an ineffective strategy for restoring riparian plant communities in regions such as LCRB where invasive species like reed canarygrass are abundant. More effective management alternatives might include short-term livestock exclusion and reintroduced targeted grazing to both reduce livestock impacts and control reed canarygrass dominance. Close

• 8. [Article] Climate-Suitable Planting as a Strategy for Maintaining Forest Productivity and Functional Diversity

  Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity ...

  Citation × Citation Citation Abstract Copy Title: Climate-Suitable Planting as a Strategy for Maintaining Forest Productivity and Functional Diversity Author: Duveneck, Matthew Joshua, Scheller, Robert M. Year: 2015 Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity in forests under current management and climate change. We evaluated the efficacy of planting climate-suitable tree species (CSP), those tree species with current or historic distributions immediately south of a focal landscape, to maintain or increase aboveground biomass, productivity, and species and functional diversity. We modeled forest change with the LANDIS-II forest simulation model for 100 years (2000–2100) at a 2-ha cell resolution and five-year time steps within two landscapes in the Great Lakes region (northeastern Minnesota and northern lower Michigan, USA). We compared current climate to low- and high-emission futures. We simulated a low-emission climate future with the Intergovernmental Panel on Climate Change (IPCC) 2007 B1 emission scenario and the Parallel Climate Model Global Circulation Model (GCM). We simulated a high-emission climate future with the IPCC A1FI emission scenario and the Geophysical Fluid Dynamics Laboratory (GFDL) GCM. We compared current forest management practices (business-asusual) to CSP management. In the CSP scenario, we simulated a target planting of 5.28% and 4.97% of forested area per five-year time step in the Minnesota and Michigan landscapes, respectively. We found that simulated CSP species successfully established in both landscapes under all climate scenarios. The presence of CSP species generally increased simulated aboveground biomass. Species diversity increased due to CSP; however, the effect on functional diversity was variable. Because the planted species were functionally similar to many native species, CSP did not result in a consistent increase nor decrease in functional diversity. These results provide an assessment of the potential efficacy and limitations of CSP management. These results have management implications for sites where diversity and productivity are expected to decline. Future efforts to restore a specific species or forest type may not be possible, but CSP may sustain a more general ecosystem service (e.g., aboveground biomass). Title: Climate-Suitable Planting as a Strategy for Maintaining Forest Productivity and Functional Diversity Author: Duveneck, Matthew Joshua, Scheller, Robert M. Year: 2015 Within the time frame of the longevity of tree species, climate change will change faster than the ability of natural tree migration. Migration lags may result in reduced productivity and reduced diversity in forests under current management and climate change. We evaluated the efficacy of planting climate-suitable tree species (CSP), those tree species with current or historic distributions immediately south of a focal landscape, to maintain or increase aboveground biomass, productivity, and species and functional diversity. We modeled forest change with the LANDIS-II forest simulation model for 100 years (2000–2100) at a 2-ha cell resolution and five-year time steps within two landscapes in the Great Lakes region (northeastern Minnesota and northern lower Michigan, USA). We compared current climate to low- and high-emission futures. We simulated a low-emission climate future with the Intergovernmental Panel on Climate Change (IPCC) 2007 B1 emission scenario and the Parallel Climate Model Global Circulation Model (GCM). We simulated a high-emission climate future with the IPCC A1FI emission scenario and the Geophysical Fluid Dynamics Laboratory (GFDL) GCM. We compared current forest management practices (business-asusual) to CSP management. In the CSP scenario, we simulated a target planting of 5.28% and 4.97% of forested area per five-year time step in the Minnesota and Michigan landscapes, respectively. We found that simulated CSP species successfully established in both landscapes under all climate scenarios. The presence of CSP species generally increased simulated aboveground biomass. Species diversity increased due to CSP; however, the effect on functional diversity was variable. Because the planted species were functionally similar to many native species, CSP did not result in a consistent increase nor decrease in functional diversity. These results provide an assessment of the potential efficacy and limitations of CSP management. These results have management implications for sites where diversity and productivity are expected to decline. Future efforts to restore a specific species or forest type may not be possible, but CSP may sustain a more general ecosystem service (e.g., aboveground biomass). Close

• 9. [Article] Fish Species Introductions Provide Novel Insights into the Patterns and Drivers of Phylogenetic Structure in Freshwaters

  Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. ...

  Citation × Citation Citation Abstract Copy Title: Fish Species Introductions Provide Novel Insights into the Patterns and Drivers of Phylogenetic Structure in Freshwaters Author: Strecker, Angela L., Olden, Julian D. Year: 2014 Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin's naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species. Title: Fish Species Introductions Provide Novel Insights into the Patterns and Drivers of Phylogenetic Structure in Freshwaters Author: Strecker, Angela L., Olden, Julian D. Year: 2014 Despite long-standing interest of terrestrial ecologists, freshwater ecosystems are a fertile, yet unappreciated, testing ground for applying community phylogenetics to uncover mechanisms of species assembly. We quantify phylogenetic clustering and overdispersion of native and non-native fishes of a large river basin in the American Southwest to test for the mechanisms (environmental filtering versus competitive exclusion) and spatial scales influencing community structure. Contrary to expectations, non-native species were phylogenetically clustered and related to natural environmental conditions, whereas native species were not phylogenetically structured, likely reflecting human-related changes to the basin. The species that are most invasive (in terms of ecological impacts) tended to be the most phylogenetically divergent from natives across watersheds, but not within watersheds, supporting the hypothesis that Darwin's naturalization conundrum is driven by the spatial scale. Phylogenetic distinctiveness may facilitate non-native establishment at regional scales, but environmental filtering restricts local membership to closely related species with physiological tolerances for current environments. By contrast, native species may have been phylogenetically clustered in historical times, but species loss from contemporary populations by anthropogenic activities has likely shaped the phylogenetic signal. Our study implies that fundamental mechanisms of community assembly have changed, with fundamental consequences for the biogeography of both native and non-native species. Close

• 10. [Article] An Investigation of Invasion: Boater Knowledge Concerning Aquatic Invasive Species and the Influence of the New Zealand Mud Snail on Benthic Food Webs

  Invasive species are second only to habitat loss as a leading cause of native species displacement and the management of invasive species costs hundreds of billions annually. Invasion is often conceptualized ...

  Citation × Citation Citation Abstract Copy Title: An Investigation of Invasion: Boater Knowledge Concerning Aquatic Invasive Species and the Influence of the New Zealand Mud Snail on Benthic Food Webs Author: Cimino, Samuel Anthony Year: 2016 Invasive species are second only to habitat loss as a leading cause of native species displacement and the management of invasive species costs hundreds of billions annually. Invasion is often conceptualized as a series of stages (Transport, Introduction, Establishment, and Spread), which encourages ecologists to isolate factors that might enable a species to pass from one stage to another and therefore guide prevention or impact management. This thesis addresses each stage of invasion and attempts to determine where management might succeed in preventing invasion or minimizing impacts. The transport and introduction of aquatic invasive species (AIS) was analyzed by conducting a three tier human subjects survey at Tenmile Lake, Oregon over a two year period in which a public boat wash station was built and installed. Assessing boater knowledge of AIS and understanding proper boat cleaning procedure is useful in determining the threat of transport and introduction as overland boater movements is a major vector of AIS. The comparison between pre- and post- boat wash surveys indicate that there is a disconnect between what boaters say they will do and how they actually behave. While 75.9% of boaters from the pre-survey claimed they would use a boat wash station at Tenmile Lake, only 38.5% of post-survey boaters were observed using the station. Furthermore, the surveys identified knowledge gaps of boaters' awareness of AIS. More than 20.0% of boaters surveyed could not verbally name any AIS. To better understand the establishment and spread stages of invasion, I examined the influence of a specific AIS, the New Zealand mud snail (Potamopyrgus antipodarum; NZMS), on benthic food webs throughout three very different aquatic ecosystems (lakes, rivers, and estuaries). Samples of benthic lake, river, and estuarine invertebrates were collected, identified, and counted, and stable isotope analyses (SIA) were conducted on several components of the food web. NZMS densities were found to be dynamic, with population densities fluctuating over time and between locations. A significant negative relationship between NZMS density and community diversity across all ecosystems was found. However, the densities of specific feeding groups had varying positive (omnivores) and negative (herbivores) correlations with NZMS densities. Furthermore, SIA indicated that NZMS don't appear to be competing with native macroinvertebrates for the same food source. NZMS were found to have different influences on each invaded ecosystem, thus management of this particular AIS is difficult once established and spreading. The results of this thesis suggest that prevention of the transport and introduction of NZMS needs to be the focus for future management. Preventative management should include public outreach regarding AIS and proper boat cleaning procedure, and management should also emphasize the need for regional policies and regulations on the transport of AIS rather than site or state specific policies and regulations. Title: An Investigation of Invasion: Boater Knowledge Concerning Aquatic Invasive Species and the Influence of the New Zealand Mud Snail on Benthic Food Webs Author: Cimino, Samuel Anthony Year: 2016 Invasive species are second only to habitat loss as a leading cause of native species displacement and the management of invasive species costs hundreds of billions annually. Invasion is often conceptualized as a series of stages (Transport, Introduction, Establishment, and Spread), which encourages ecologists to isolate factors that might enable a species to pass from one stage to another and therefore guide prevention or impact management. This thesis addresses each stage of invasion and attempts to determine where management might succeed in preventing invasion or minimizing impacts. The transport and introduction of aquatic invasive species (AIS) was analyzed by conducting a three tier human subjects survey at Tenmile Lake, Oregon over a two year period in which a public boat wash station was built and installed. Assessing boater knowledge of AIS and understanding proper boat cleaning procedure is useful in determining the threat of transport and introduction as overland boater movements is a major vector of AIS. The comparison between pre- and post- boat wash surveys indicate that there is a disconnect between what boaters say they will do and how they actually behave. While 75.9% of boaters from the pre-survey claimed they would use a boat wash station at Tenmile Lake, only 38.5% of post-survey boaters were observed using the station. Furthermore, the surveys identified knowledge gaps of boaters' awareness of AIS. More than 20.0% of boaters surveyed could not verbally name any AIS. To better understand the establishment and spread stages of invasion, I examined the influence of a specific AIS, the New Zealand mud snail (Potamopyrgus antipodarum; NZMS), on benthic food webs throughout three very different aquatic ecosystems (lakes, rivers, and estuaries). Samples of benthic lake, river, and estuarine invertebrates were collected, identified, and counted, and stable isotope analyses (SIA) were conducted on several components of the food web. NZMS densities were found to be dynamic, with population densities fluctuating over time and between locations. A significant negative relationship between NZMS density and community diversity across all ecosystems was found. However, the densities of specific feeding groups had varying positive (omnivores) and negative (herbivores) correlations with NZMS densities. Furthermore, SIA indicated that NZMS don't appear to be competing with native macroinvertebrates for the same food source. NZMS were found to have different influences on each invaded ecosystem, thus management of this particular AIS is difficult once established and spreading. The results of this thesis suggest that prevention of the transport and introduction of NZMS needs to be the focus for future management. Preventative management should include public outreach regarding AIS and proper boat cleaning procedure, and management should also emphasize the need for regional policies and regulations on the transport of AIS rather than site or state specific policies and regulations. Close