Search

Search Results

• 201. [Article] Monitoring design for riparian forests in the Pacific Northwest : research plan

  The goal of this project is to recommend a broadly-acceptale efficient and effective methodology for characterizing streamside riparian attributes in forested settings at the site grain for regional monitoring. ...

  Citation × Citation Citation Abstract Copy Title: Monitoring design for riparian forests in the Pacific Northwest : research plan Author: Bollman, Mike, National Health and Environmental Effects Laboratory., Oregon State University, Stepp, Jennifer, United States. Environmental Protection Agency. ǂb Office of Research and Development, United States. Forest Service, Barker, Jerry R., Bradshaw, Gay, Ringold, Paul L., Cline, Steven Paul, Carson, Ward, Dynamac Corporation, Fiorella, Maria R. The goal of this project is to recommend a broadly-acceptale efficient and effective methodology for characterizing streamside riparian attributes in forested settings at the site grain for regional monitoring. The authors consider monitoring design in the context of three interacting constraints: ecological functions, capabilities of technologies, and user needs. The focus is on fine grained remote methods. Comparison between candidate selected monitoring systems provides for an initial formulation of a monitoring design. A series of evaluations of these initial formulations provides for an initial recommendation. With the state's interest in the status of coastal fishes, and the programmatic interest of EPA's Western Ecology Division, the areas selected for study are in the Oregon coastal province and the Willamette basin. Title: Monitoring design for riparian forests in the Pacific Northwest : research plan Author: Bollman, Mike, National Health and Environmental Effects Laboratory., Oregon State University, Stepp, Jennifer, United States. Environmental Protection Agency. ǂb Office of Research and Development, United States. Forest Service, Barker, Jerry R., Bradshaw, Gay, Ringold, Paul L., Cline, Steven Paul, Carson, Ward, Dynamac Corporation, Fiorella, Maria R. The goal of this project is to recommend a broadly-acceptale efficient and effective methodology for characterizing streamside riparian attributes in forested settings at the site grain for regional monitoring. The authors consider monitoring design in the context of three interacting constraints: ecological functions, capabilities of technologies, and user needs. The focus is on fine grained remote methods. Comparison between candidate selected monitoring systems provides for an initial formulation of a monitoring design. A series of evaluations of these initial formulations provides for an initial recommendation. With the state's interest in the status of coastal fishes, and the programmatic interest of EPA's Western Ecology Division, the areas selected for study are in the Oregon coastal province and the Willamette basin. Close

• 202. [Article] Terrestrial lichen and bryophyte communities of the Blue Mountains in Northeast Oregon

  Although terrestrial lichens and bryophytes are common in upland plant communities of the Blue Mountains in northeast Oregon, research on cryptogam communities in this region is wanting. Studies have shown ...

  Citation × Citation Citation Abstract Copy Title: Terrestrial lichen and bryophyte communities of the Blue Mountains in Northeast Oregon Author: Hardman, Amanda Although terrestrial lichens and bryophytes are common in upland plant communities of the Blue Mountains in northeast Oregon, research on cryptogam communities in this region is wanting. Studies have shown that lichens and bryophytes can reduce soil erosion and increase soil fertility in other semiarid habitats of North America. Understanding the particular roles terrestrial lichens and bryophytes play in their ecosystems and how they react to anthropogenic disturbances is part of making sound management decisions. Managers in the Blue Mountains are now dealing with heavy fuel loads in forested habitats that were impacted by mountain pine beetles, western spruce budworm infestations, Douglas fir dwarf mistletoe, and drought from the 1970's into the 1990's. To better understand how cryptogam communities respond to fuels reduction treatments in insect impacted Abies grandis classified forests of the central Blue Mountains, we compared species composition of logged and burned stands to stands that have not been treated in forty years. We found early colonizing species to be much more frequent in treated sites (logged and burned) while later seral species occurred more often in untreated stands. Because untreated stands had more microsite heterogeneity (coarse woody debris as well as bare soils) there was generally a higher diversity of species than in treated sites. A comparison of the composition of cryptogam communities in these degraded forests to 'healthy' stands in the central Blue Mountains is difficult because unaffected stands are scarce and literature on such communities previous to the insect epidemics is lacking. To get a better idea of the potential that exists for terrestrial lichen and bryophyte community composition, this research was expanded to other common upland habitats in the area. In total 53 sites in five different plant community types were investigated (Abies grandis, Pinus ponderosa, Pinus contorta, Poa secunda grasslands, and Artemisia rigida steppe). Lichen and bryophyte composition and environmental characteristics were compared across sites using multivariate analyses. This research has provided some basic information on community composition in upland habitats of the Blue Mountains. Soil characteristics had the strongest correlation to community composition. Habitats with sparsely vegetated, shallow, rocky soils (bunchgrass, Artemisia rigida, Pinus ponderosa) had very different cryptogam presence than those with deep soils covered by coarse woody debris and denser vegetation (Abies grandis and Pinus contorta forests). While investigating dry bunchgrass habitat of the region an unattached form of Grimmia ovalis was found on many sites with shallow soils and sparse vegetation. Although this moss is commonly known on rock in western North America, it has not yet been reported as unattached in North America. It has, however, been recorded from Africa and Venezuela. Unattached mosses, or moss balls, form when a force, such as frost heaving, cleaves a moss clump from a substrate. That same force, or another, will rotate the clump exposing alternating sides to growth. The formation of moss balls in northeast Oregon are likely created by freeze thaw cycles. More research on their biology and habitat is needed to verify this theory. Title: Terrestrial lichen and bryophyte communities of the Blue Mountains in Northeast Oregon Author: Hardman, Amanda Although terrestrial lichens and bryophytes are common in upland plant communities of the Blue Mountains in northeast Oregon, research on cryptogam communities in this region is wanting. Studies have shown that lichens and bryophytes can reduce soil erosion and increase soil fertility in other semiarid habitats of North America. Understanding the particular roles terrestrial lichens and bryophytes play in their ecosystems and how they react to anthropogenic disturbances is part of making sound management decisions. Managers in the Blue Mountains are now dealing with heavy fuel loads in forested habitats that were impacted by mountain pine beetles, western spruce budworm infestations, Douglas fir dwarf mistletoe, and drought from the 1970's into the 1990's. To better understand how cryptogam communities respond to fuels reduction treatments in insect impacted Abies grandis classified forests of the central Blue Mountains, we compared species composition of logged and burned stands to stands that have not been treated in forty years. We found early colonizing species to be much more frequent in treated sites (logged and burned) while later seral species occurred more often in untreated stands. Because untreated stands had more microsite heterogeneity (coarse woody debris as well as bare soils) there was generally a higher diversity of species than in treated sites. A comparison of the composition of cryptogam communities in these degraded forests to 'healthy' stands in the central Blue Mountains is difficult because unaffected stands are scarce and literature on such communities previous to the insect epidemics is lacking. To get a better idea of the potential that exists for terrestrial lichen and bryophyte community composition, this research was expanded to other common upland habitats in the area. In total 53 sites in five different plant community types were investigated (Abies grandis, Pinus ponderosa, Pinus contorta, Poa secunda grasslands, and Artemisia rigida steppe). Lichen and bryophyte composition and environmental characteristics were compared across sites using multivariate analyses. This research has provided some basic information on community composition in upland habitats of the Blue Mountains. Soil characteristics had the strongest correlation to community composition. Habitats with sparsely vegetated, shallow, rocky soils (bunchgrass, Artemisia rigida, Pinus ponderosa) had very different cryptogam presence than those with deep soils covered by coarse woody debris and denser vegetation (Abies grandis and Pinus contorta forests). While investigating dry bunchgrass habitat of the region an unattached form of Grimmia ovalis was found on many sites with shallow soils and sparse vegetation. Although this moss is commonly known on rock in western North America, it has not yet been reported as unattached in North America. It has, however, been recorded from Africa and Venezuela. Unattached mosses, or moss balls, form when a force, such as frost heaving, cleaves a moss clump from a substrate. That same force, or another, will rotate the clump exposing alternating sides to growth. The formation of moss balls in northeast Oregon are likely created by freeze thaw cycles. More research on their biology and habitat is needed to verify this theory. Close

• 203. [Article] Carbon Dynamics in Response to Land Cover Change in Tropical Peatlands, Kalimantan, Indonesia

  This study focuses in providing the knowledge on carbon (C) stocks, emission and ecosystem productivity related to land use/land cover change in tropical peatlands. The field research activities were ...

  Citation × Citation Citation Abstract Copy Title: Carbon Dynamics in Response to Land Cover Change in Tropical Peatlands, Kalimantan, Indonesia Author: Basuki, Imam This study focuses in providing the knowledge on carbon (C) stocks, emission and ecosystem productivity related to land use/land cover change in tropical peatlands. The field research activities were conducted for about 17 months between August 2013 to December 2015, at Pematang Gadung peat dome (peat depth up to 10.5 m), Ketapang Regency, West Kalimantan, Indonesia. The objectives of this study were: a). to quantify C stocks of tropical coastal peat swamp forest, and the potential impact of forest degradation due to draining and logging activities on the forest’s carbon stocks; b). to examine the change in ecosystem C stocks and the potential C emissions in relation to land conversion from intact peat swamp forest (PSF) to logged peat forest (LPSF), early seral (ES) and oil palm plantation (OP); and c). to estimate net primary production (NPP) and net ecosystem production (NEP) in peat swamp forests, logged peat forest, early seral and smallholder - oil palm plantations. The intact peat forest sites have higher total aboveground C stocks (125 Mg C ha-1) than the logged peat forest sites (77 Mg C ha-1). Mean depths of the LPSF was 725 cm and the PSF was 915 cm (p= 0.06). Mean peat carbon stocks at PSF was 4,243 Mg C ha-1, higher than at LPSF that was 3,675 Mg C ha-1. Logging and draining had reduced the biomass of trees and the peat carbon pools. My study demonstrated that tropical coastal PSF has the largest total carbon stocks among terrestrial ecosystems on earth. The large carbon stocks and high rates of PSF degradation, points to the relevance for inclusion of PSF in nationally appropriate climate change mitigation and adaptation strategies. The mean ecosystem carbon stock for the PSF sites was 4,401 Mg C ha-1. Ecosystem C stocks of LPSF, ES and OP was 3,768, 3,147, and 3,442 Mg C ha-1, respectively. PSF stocks was significantly higher than the degraded land covers. At all sites, soils comprised > 96% of the mean ecosystem carbon stock. Using the estimation based on ecosystem carbon loss to total peat depths, the conversion of PSF to LPSF, ES and OP was estimated to result in a net loss of 1,982, 4,259 and 3,176 Mg C-CO2 ha-1, respectively. My results confirm that land cover change significantly impacted soil properties and reduced ecosystem carbon stocks. The tropical peatlands need urgent and significant efforts in conservation and restoration, to regain its function as a C sink and mitigate climate change. I found that land use/land cover change resulted in large shifts in NPP and NEP. LPSF, ES and OP have significantly lower NPP (11.1 Mg C ha-1 yr-1, 10.8 Mg C ha-1 yr-1 and 3.7 Mg C ha-1 yr-1, respectively) than PSF (13.2 Mg C ha-1 yr-1). ES showed lower heterotrophic respiration (30.7 Mg CO2 ha-1 yr-1) than PSF, LPSF and OP (37.7 Mg CO2 ha-1 yr-1, 40.7 Mg CO2 ha-1 yr-1, 38.7 Mg CO2 ha-1 yr-1, respectively). LPSF and OP were net carbon sources; they have negative mean NEP values (-0.1 Mg CO2-e ha-1 yr-1 and -25.1 Mg CO2-e ha-1 yr-1, respectively). In contrast PSF and ES were net carbon sinks (10.8 Mg CO2-e ha-1 yr-1 and 9.1 CCO2 ha-1 yr-1, respectively). PSF is among the most productive of terrestrial ecosystems, with an NPP exceeding that of many tropical rain forests and similar to the most productive mangrove ecosystems. I found that land use decreases productivity of the LPSF and OP sites. The ES had a similar NEP to the PSF, but frequent fires in this ecosystem likely offset carbon gains during the fire intervals. Land use change and forest degradation have shifted tropical PSFs from net carbon sinks to net carbon sources. My study demonstrated that land conversion in tropical peat swamp forests should be halted and degraded peatlands need to be restored in order to mitigate climate change. Title: Carbon Dynamics in Response to Land Cover Change in Tropical Peatlands, Kalimantan, Indonesia Author: Basuki, Imam This study focuses in providing the knowledge on carbon (C) stocks, emission and ecosystem productivity related to land use/land cover change in tropical peatlands. The field research activities were conducted for about 17 months between August 2013 to December 2015, at Pematang Gadung peat dome (peat depth up to 10.5 m), Ketapang Regency, West Kalimantan, Indonesia. The objectives of this study were: a). to quantify C stocks of tropical coastal peat swamp forest, and the potential impact of forest degradation due to draining and logging activities on the forest’s carbon stocks; b). to examine the change in ecosystem C stocks and the potential C emissions in relation to land conversion from intact peat swamp forest (PSF) to logged peat forest (LPSF), early seral (ES) and oil palm plantation (OP); and c). to estimate net primary production (NPP) and net ecosystem production (NEP) in peat swamp forests, logged peat forest, early seral and smallholder - oil palm plantations. The intact peat forest sites have higher total aboveground C stocks (125 Mg C ha-1) than the logged peat forest sites (77 Mg C ha-1). Mean depths of the LPSF was 725 cm and the PSF was 915 cm (p= 0.06). Mean peat carbon stocks at PSF was 4,243 Mg C ha-1, higher than at LPSF that was 3,675 Mg C ha-1. Logging and draining had reduced the biomass of trees and the peat carbon pools. My study demonstrated that tropical coastal PSF has the largest total carbon stocks among terrestrial ecosystems on earth. The large carbon stocks and high rates of PSF degradation, points to the relevance for inclusion of PSF in nationally appropriate climate change mitigation and adaptation strategies. The mean ecosystem carbon stock for the PSF sites was 4,401 Mg C ha-1. Ecosystem C stocks of LPSF, ES and OP was 3,768, 3,147, and 3,442 Mg C ha-1, respectively. PSF stocks was significantly higher than the degraded land covers. At all sites, soils comprised > 96% of the mean ecosystem carbon stock. Using the estimation based on ecosystem carbon loss to total peat depths, the conversion of PSF to LPSF, ES and OP was estimated to result in a net loss of 1,982, 4,259 and 3,176 Mg C-CO2 ha-1, respectively. My results confirm that land cover change significantly impacted soil properties and reduced ecosystem carbon stocks. The tropical peatlands need urgent and significant efforts in conservation and restoration, to regain its function as a C sink and mitigate climate change. I found that land use/land cover change resulted in large shifts in NPP and NEP. LPSF, ES and OP have significantly lower NPP (11.1 Mg C ha-1 yr-1, 10.8 Mg C ha-1 yr-1 and 3.7 Mg C ha-1 yr-1, respectively) than PSF (13.2 Mg C ha-1 yr-1). ES showed lower heterotrophic respiration (30.7 Mg CO2 ha-1 yr-1) than PSF, LPSF and OP (37.7 Mg CO2 ha-1 yr-1, 40.7 Mg CO2 ha-1 yr-1, 38.7 Mg CO2 ha-1 yr-1, respectively). LPSF and OP were net carbon sources; they have negative mean NEP values (-0.1 Mg CO2-e ha-1 yr-1 and -25.1 Mg CO2-e ha-1 yr-1, respectively). In contrast PSF and ES were net carbon sinks (10.8 Mg CO2-e ha-1 yr-1 and 9.1 CCO2 ha-1 yr-1, respectively). PSF is among the most productive of terrestrial ecosystems, with an NPP exceeding that of many tropical rain forests and similar to the most productive mangrove ecosystems. I found that land use decreases productivity of the LPSF and OP sites. The ES had a similar NEP to the PSF, but frequent fires in this ecosystem likely offset carbon gains during the fire intervals. Land use change and forest degradation have shifted tropical PSFs from net carbon sinks to net carbon sources. My study demonstrated that land conversion in tropical peat swamp forests should be halted and degraded peatlands need to be restored in order to mitigate climate change. Close

• 204. [Article] Realized and potential climate responses of lichen and bryophyte communities in a national forest inventory

  Climate and terrestrial vegetation have had mutual feedbacks for nearly five hundred million years, yet both are now departing from recent historical norms, with uncertain implications for forest ecosystems. ...

  Citation × Citation Citation Abstract Copy Title: Realized and potential climate responses of lichen and bryophyte communities in a national forest inventory Author: Smith, Robert J. Climate and terrestrial vegetation have had mutual feedbacks for nearly five hundred million years, yet both are now departing from recent historical norms, with uncertain implications for forest ecosystems. This dissertation outlines the current and potential future climate responses of lichen and bryophyte communities in the United States as part of a national forest inventory. The first task was to identify influences on carbon and nitrogen storage of moss and lichen “ground layers” in subarctic interior Alaska. Nutrient stores were more sensitive to local vegetation and topography than regional macroclimate. Nutrients and biomass were greatest among apparently less disturbed stands. This suggests that climatic changes could diminish ground layer nutrient storage indirectly if they promote intensifying wildfire regimes or expansions of competitive vascular vegetation. Turning to focus on species diversity, the next task was to quantify the strength of relationship between epiphytic lichen community composition and macroclimate across the 4,000 km-long swath of the U.S. Pacific coastal states. The strongest fitting lichen response gradients involved precipitation, temperature, and a heat-moisture index. Lichen indicator species (diagnostic of ten defined climate zones) emerged as useful monitoring tools because their abundance changes could signal shifting climate zone boundaries. After establishing key present-day climatic relationships, the next task was to pinpoint nationwide locations where epiphytic lichen communities will be most vulnerable to species losses under current and future warming scenarios. Novel niche-based metrics revealed greatest vulnerability among supposedly “warm-adapted” communities in southern/lowland locations, contrary to usual assumptions centering on cooler northern/montane habitats. Vulnerability analyses can steer conservation and monitoring attention to specific locations where warming is most expected to affect ecological communities. The final task, to anticipate how warming will impact individual lichen performance, was addressed by quantifying how experimental climate treatments (whole-ecosystem warming and CO2 additions) affected growth of the boreal epiphytic lichen species Evernia mesomorpha. Over just one year, incremental warming and concurrent drying caused progressive growth declines and biomass losses among individual transplants. Such warming-induced biomass losses of epiphytic lichens could precede local population extinctions and regional range contractions. Overall, this dissertation weaves together multiple lines of evidence from nutrient, diversity and growth responses to indicate the ecological effects of climate and climatic changes on vegetation in a national forest inventory context. This work suggests a pathway for integrating lichen and bryophyte responses into nationwide climate monitoring to address emergent interactions between humans, vegetation, and the global climate commons. Title: Realized and potential climate responses of lichen and bryophyte communities in a national forest inventory Author: Smith, Robert J. Climate and terrestrial vegetation have had mutual feedbacks for nearly five hundred million years, yet both are now departing from recent historical norms, with uncertain implications for forest ecosystems. This dissertation outlines the current and potential future climate responses of lichen and bryophyte communities in the United States as part of a national forest inventory. The first task was to identify influences on carbon and nitrogen storage of moss and lichen “ground layers” in subarctic interior Alaska. Nutrient stores were more sensitive to local vegetation and topography than regional macroclimate. Nutrients and biomass were greatest among apparently less disturbed stands. This suggests that climatic changes could diminish ground layer nutrient storage indirectly if they promote intensifying wildfire regimes or expansions of competitive vascular vegetation. Turning to focus on species diversity, the next task was to quantify the strength of relationship between epiphytic lichen community composition and macroclimate across the 4,000 km-long swath of the U.S. Pacific coastal states. The strongest fitting lichen response gradients involved precipitation, temperature, and a heat-moisture index. Lichen indicator species (diagnostic of ten defined climate zones) emerged as useful monitoring tools because their abundance changes could signal shifting climate zone boundaries. After establishing key present-day climatic relationships, the next task was to pinpoint nationwide locations where epiphytic lichen communities will be most vulnerable to species losses under current and future warming scenarios. Novel niche-based metrics revealed greatest vulnerability among supposedly “warm-adapted” communities in southern/lowland locations, contrary to usual assumptions centering on cooler northern/montane habitats. Vulnerability analyses can steer conservation and monitoring attention to specific locations where warming is most expected to affect ecological communities. The final task, to anticipate how warming will impact individual lichen performance, was addressed by quantifying how experimental climate treatments (whole-ecosystem warming and CO2 additions) affected growth of the boreal epiphytic lichen species Evernia mesomorpha. Over just one year, incremental warming and concurrent drying caused progressive growth declines and biomass losses among individual transplants. Such warming-induced biomass losses of epiphytic lichens could precede local population extinctions and regional range contractions. Overall, this dissertation weaves together multiple lines of evidence from nutrient, diversity and growth responses to indicate the ecological effects of climate and climatic changes on vegetation in a national forest inventory context. This work suggests a pathway for integrating lichen and bryophyte responses into nationwide climate monitoring to address emergent interactions between humans, vegetation, and the global climate commons. Close

• 205. [Article] Ultraviolet radiation as an environmental stressor of amphibians

  My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial ...

  Citation × Citation Citation Abstract Copy Title: Ultraviolet radiation as an environmental stressor of amphibians Author: Bancroft, Betsy A. My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial and aquatic systems. I used meta-analysis to quantify the effects of UVB radiation on a diversity of aquatic organisms (Chapter 2). UVB negatively affects aquatic organisms by reducing both survival and growth. In particular, UVB reduces growth of embryos more than any other life history stage. Some taxonomic groups may be more affected by UVB radiation than others. In our analysis, the growth of members of the kingdom Protozoa was suppressed by UVB radiation to a greater degree than any other kingdom. These analyses suggest that UVB is an important stressor in both freshwater and marine systems. Amphibians are a common component of freshwater systems and are experiencing world-wide population declines. These declines may be due to a number of causes including habitat loss, introduced species, global climate change, disease, toxic chemicals and UVB radiation. I used meta-analytic techniques to quantify the effects of UVB radiation on amphibians. By synthesizing the results of 41 articles on the effects of UVB radiation on amphibians (Chapter 3), I found a nearly 2-fold reduction in survival of amphibians exposed to UVB radiation. Salamanders (caudates) appear to be more susceptible to damage from UVB than frogs or toads (anurans). Moreover, survival of larvae was much lower than survival of embryos or metamorphic individuals under UVB radiation. In addition, I used factorial meta-analytic techniques to explore the interaction between UVB radiation and other stressors in amphibian habitats. UVB radiation acted synergistically with other stressors to reduce survival of amphibians. Behavioral avoidance of UVB radiation may help mediate the negative effects of UVB radiation on amphibians. In aquatic systems, behavioral avoidance usually requires movement out of shallow water, where UVB levels can be high, into deeper waters with lower UVB transmittance. However, these two microhabitats have very different thermal profiles, creating a trade-off between exploiting warm waters with high UVB levels and avoiding UVB by seeking cooler, deeper regions of ponds. I explored the microhabitat use of larvae of four species through a series of laboratory experiments, field experiments, and observational field transects at three different amphibian habitats (Chapter 4). Larvae did not avoid UVB radiation in either the laboratory or field experiments. Larvae in thermal gradients selected relatively high temperatures regardless of the UVB exposure at these temperatures. In field transects, salamander larvae were most common in deeper, cooler waters where UVB levels were lower. In contrast, anuran larvae were frequently observed in the warmer and shallower regions of each habitat. These regions also had the highest UVB levels, suggesting that anuran larvae are exposed to high levels of UVB due to thermoregulatory behavior. Behavioral avoidance of UVB radiation is not the only mechanism amphibians may use to prevent damage from UVB. Pigments such as melanin may allow larvae to exploit warm shallow waters by absorbing harmful UVB radiation before it causes cellular damage. I tested the efficacy of melanin as a photoprotective pigment in the larvae of two species, Rana cascadae and Pseudacris regilla (Chapter 5). I found no evidence of a photoprotective function for melanin in these larvae. In contrast, lighter colored tadpoles grew more under UVB radiation compared to darker colored tadpoles. Overall, exposure to UVB reduced survival of P. regilla larvae and reduced growth of R. cascadae larvae. Larvae of both of these species were frequently observed in very shallow water with intense solar radiation. This thesis emphasizes the importance of UVB radiation as an environmental stressor in aquatic habitats. Many aquatic organisms are negatively affected by UVB exposure. My thesis work quantitatively demonstrated that UVB radiation is one factor that reduces survival of amphibians and suggests that some species are exposed to high levels of UVB radiation in natural habitats. While UVB radiation is not the sole cause of amphibian population declines, my work suggests that UVB radiation is an important stressor for amphibians that should not be overlooked. In addition, UVB radiation is clearly an important stressor for many other aquatic organisms. Future work should consider the effects of UVB in aquatic systems, particularly the effects of UVB radiation on community structure and ecosystem function. Title: Ultraviolet radiation as an environmental stressor of amphibians Author: Bancroft, Betsy A. My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial and aquatic systems. I used meta-analysis to quantify the effects of UVB radiation on a diversity of aquatic organisms (Chapter 2). UVB negatively affects aquatic organisms by reducing both survival and growth. In particular, UVB reduces growth of embryos more than any other life history stage. Some taxonomic groups may be more affected by UVB radiation than others. In our analysis, the growth of members of the kingdom Protozoa was suppressed by UVB radiation to a greater degree than any other kingdom. These analyses suggest that UVB is an important stressor in both freshwater and marine systems. Amphibians are a common component of freshwater systems and are experiencing world-wide population declines. These declines may be due to a number of causes including habitat loss, introduced species, global climate change, disease, toxic chemicals and UVB radiation. I used meta-analytic techniques to quantify the effects of UVB radiation on amphibians. By synthesizing the results of 41 articles on the effects of UVB radiation on amphibians (Chapter 3), I found a nearly 2-fold reduction in survival of amphibians exposed to UVB radiation. Salamanders (caudates) appear to be more susceptible to damage from UVB than frogs or toads (anurans). Moreover, survival of larvae was much lower than survival of embryos or metamorphic individuals under UVB radiation. In addition, I used factorial meta-analytic techniques to explore the interaction between UVB radiation and other stressors in amphibian habitats. UVB radiation acted synergistically with other stressors to reduce survival of amphibians. Behavioral avoidance of UVB radiation may help mediate the negative effects of UVB radiation on amphibians. In aquatic systems, behavioral avoidance usually requires movement out of shallow water, where UVB levels can be high, into deeper waters with lower UVB transmittance. However, these two microhabitats have very different thermal profiles, creating a trade-off between exploiting warm waters with high UVB levels and avoiding UVB by seeking cooler, deeper regions of ponds. I explored the microhabitat use of larvae of four species through a series of laboratory experiments, field experiments, and observational field transects at three different amphibian habitats (Chapter 4). Larvae did not avoid UVB radiation in either the laboratory or field experiments. Larvae in thermal gradients selected relatively high temperatures regardless of the UVB exposure at these temperatures. In field transects, salamander larvae were most common in deeper, cooler waters where UVB levels were lower. In contrast, anuran larvae were frequently observed in the warmer and shallower regions of each habitat. These regions also had the highest UVB levels, suggesting that anuran larvae are exposed to high levels of UVB due to thermoregulatory behavior. Behavioral avoidance of UVB radiation is not the only mechanism amphibians may use to prevent damage from UVB. Pigments such as melanin may allow larvae to exploit warm shallow waters by absorbing harmful UVB radiation before it causes cellular damage. I tested the efficacy of melanin as a photoprotective pigment in the larvae of two species, Rana cascadae and Pseudacris regilla (Chapter 5). I found no evidence of a photoprotective function for melanin in these larvae. In contrast, lighter colored tadpoles grew more under UVB radiation compared to darker colored tadpoles. Overall, exposure to UVB reduced survival of P. regilla larvae and reduced growth of R. cascadae larvae. Larvae of both of these species were frequently observed in very shallow water with intense solar radiation. This thesis emphasizes the importance of UVB radiation as an environmental stressor in aquatic habitats. Many aquatic organisms are negatively affected by UVB exposure. My thesis work quantitatively demonstrated that UVB radiation is one factor that reduces survival of amphibians and suggests that some species are exposed to high levels of UVB radiation in natural habitats. While UVB radiation is not the sole cause of amphibian population declines, my work suggests that UVB radiation is an important stressor for amphibians that should not be overlooked. In addition, UVB radiation is clearly an important stressor for many other aquatic organisms. Future work should consider the effects of UVB in aquatic systems, particularly the effects of UVB radiation on community structure and ecosystem function. Close

• 206. [Article] The Response and Effect of Emergent Coastal Vegetation to Sedimentation and the Distribution of Coastal Vegetation Communities along Environmental Gradients

  Coastal marsh vegetation is an important component in maintaining marsh stability that is threatened by changes in sedimentation, sea level rise, natural and anthropogenic disturbances, and competition ...

  Citation × Citation Citation Abstract Copy Title: The Response and Effect of Emergent Coastal Vegetation to Sedimentation and the Distribution of Coastal Vegetation Communities along Environmental Gradients Author: Lemein, Todd Coastal marsh vegetation is an important component in maintaining marsh stability that is threatened by changes in sedimentation, sea level rise, natural and anthropogenic disturbances, and competition from invasive species. Vegetation has been demonstrated to reduce wave energy, increase sedimentation, and decrease erosion in tidal environments under a range of conditions. Similarities and differences between the morphology of vegetation species may play an important role in understanding the mechanism between vegetation, sedimentation, and wave energy. Diversity of species within vegetation communities has been shown to reduce the success of biological invasions from invasive species as well as increase the ability of the community to adapt to environmental changes such as inundation period (period of time vegetation is submerged partially or fully by water). The species present along coastal marshes and specifically at the interface between vegetated marsh and unvegetated mudflat provide an opportunity to better understand the interactions between vegetation and its physical setting. In this dissertation I focus on the species and vegetation communities that are present at this interface of the terrestrial and aquatic boundary to better understand how plant communities may be characterized, how they respond to disturbance, how they are distributed, and how they may influence the physical environment in which they grow. In Chapter two, I explore the ability to use image analysis and the lateral obstruction of vegetation to describe a species density, height and diameter and evaluate the tradeoffs in using image analysis over more traditional methods. In Chapter three, I evaluate the response of an emergent vegetation species, threesquare bulrush (Schoenoplectus pungens), to different depths of complete burial as could be expected from extreme storms, hurricanes, tsunamis, or restoration efforts involving sediment amendment. Chapter four describes the distribution of coastal marsh communities of the Laurentian Great Lakes along an elevational gradient beginning at the terrestrial and aquatic boundary, identifying patterns of wetland distribution, species composition, and exotic plant invasion. In Chapter five, I conclude the dissertation with an evaluation of the effects of two morphologically distinct species of emergent marsh vegetation, threesquare bulrush and Lyngbye’s sedge (Carex lyngbyei), on the sedimentation rate and variability in Tillamook Bay, OR and compare the results to the current understanding of vegetation-sediment feedback. In Chapter two, I found that for morphologically simple species, such as S. pungens, image analysis of lateral obstruction can be used to determine important morphological characteristics of a stand of vegetation including the mean stem height, density, and mean diameter. The method provides a description of the vertical variation in morphologic structure, providing a rapid analytic tool for exploring the effects of vegetation on wave and sediment interaction. However, I note that more morphologically complex species, such as sedges and grasses may not be as easily described using image analysis. In Chapter three, I determined that aboveground biomass of S. pungens would return to pre-disturbance levels following burial by up to 40 cm of mineral sediment after two years. Vegetation was observed to survive burials depths of up to 80 cm, although initially at much lower density. The aboveground height of stems were statistically similar to unburied controls after two years, which is important for the continuation of ecosystem services such as wave attenuation. The results suggest that S. pungens is capable of returning to pre-disturbance levels of biomass following large natural sedimentation events such as extreme storms, hurricanes, or tsunamis, and that burying portions of marshes with sediment as a restoration tool is not likely to harm the buried vegetation. In Chapter four I refine and describe 21 coastal vegetation communities in the Laurentian Great Lakes and the ecological gradients along which they are distributed. Latitude, agricultural intensity, site geomorphology, substrate, and water depth were found to be the significant variables that determined community distribution. Additionally, we observed an expansion of invasive plant species near areas of high anthropogenic activity such as farms and urban centers. In Chapter five, I found that there were species-specific differences in sedimentation rate and variability in Tillamook Bay, OR. Schoenoplectus pungens was found to retain more sediment than C. lyngbyei. Sedimentation rate was observed to be variable by location within the estuary. Two patterns of sediment accumulation were observed. The first occurred along vegetation gradients, with increased sedimentation farther into vegetation beds. In the second pattern, sediment accumulation was observed to be greatest at the marsh/mudflat boundary where vegetation was dense and then decreased with increasing depth into the vegetation. In conclusion, this dissertation explores the interaction of emergent wetland vegetation with environmental factors. Image analysis provides a new tool for rapid characterization of vegetation structure, a burial experiment documents Schoenoplectus pungens’ tolerance to sand burial, a field study at Tillamook, OR documents the relationship between sediment accumulation and emergent vegetation beds, and a wetland classification is developed for coastal wetlands along the Great Lakes, which includes plant communities dominated by S. pungens. Title: The Response and Effect of Emergent Coastal Vegetation to Sedimentation and the Distribution of Coastal Vegetation Communities along Environmental Gradients Author: Lemein, Todd Coastal marsh vegetation is an important component in maintaining marsh stability that is threatened by changes in sedimentation, sea level rise, natural and anthropogenic disturbances, and competition from invasive species. Vegetation has been demonstrated to reduce wave energy, increase sedimentation, and decrease erosion in tidal environments under a range of conditions. Similarities and differences between the morphology of vegetation species may play an important role in understanding the mechanism between vegetation, sedimentation, and wave energy. Diversity of species within vegetation communities has been shown to reduce the success of biological invasions from invasive species as well as increase the ability of the community to adapt to environmental changes such as inundation period (period of time vegetation is submerged partially or fully by water). The species present along coastal marshes and specifically at the interface between vegetated marsh and unvegetated mudflat provide an opportunity to better understand the interactions between vegetation and its physical setting. In this dissertation I focus on the species and vegetation communities that are present at this interface of the terrestrial and aquatic boundary to better understand how plant communities may be characterized, how they respond to disturbance, how they are distributed, and how they may influence the physical environment in which they grow. In Chapter two, I explore the ability to use image analysis and the lateral obstruction of vegetation to describe a species density, height and diameter and evaluate the tradeoffs in using image analysis over more traditional methods. In Chapter three, I evaluate the response of an emergent vegetation species, threesquare bulrush (Schoenoplectus pungens), to different depths of complete burial as could be expected from extreme storms, hurricanes, tsunamis, or restoration efforts involving sediment amendment. Chapter four describes the distribution of coastal marsh communities of the Laurentian Great Lakes along an elevational gradient beginning at the terrestrial and aquatic boundary, identifying patterns of wetland distribution, species composition, and exotic plant invasion. In Chapter five, I conclude the dissertation with an evaluation of the effects of two morphologically distinct species of emergent marsh vegetation, threesquare bulrush and Lyngbye’s sedge (Carex lyngbyei), on the sedimentation rate and variability in Tillamook Bay, OR and compare the results to the current understanding of vegetation-sediment feedback. In Chapter two, I found that for morphologically simple species, such as S. pungens, image analysis of lateral obstruction can be used to determine important morphological characteristics of a stand of vegetation including the mean stem height, density, and mean diameter. The method provides a description of the vertical variation in morphologic structure, providing a rapid analytic tool for exploring the effects of vegetation on wave and sediment interaction. However, I note that more morphologically complex species, such as sedges and grasses may not be as easily described using image analysis. In Chapter three, I determined that aboveground biomass of S. pungens would return to pre-disturbance levels following burial by up to 40 cm of mineral sediment after two years. Vegetation was observed to survive burials depths of up to 80 cm, although initially at much lower density. The aboveground height of stems were statistically similar to unburied controls after two years, which is important for the continuation of ecosystem services such as wave attenuation. The results suggest that S. pungens is capable of returning to pre-disturbance levels of biomass following large natural sedimentation events such as extreme storms, hurricanes, or tsunamis, and that burying portions of marshes with sediment as a restoration tool is not likely to harm the buried vegetation. In Chapter four I refine and describe 21 coastal vegetation communities in the Laurentian Great Lakes and the ecological gradients along which they are distributed. Latitude, agricultural intensity, site geomorphology, substrate, and water depth were found to be the significant variables that determined community distribution. Additionally, we observed an expansion of invasive plant species near areas of high anthropogenic activity such as farms and urban centers. In Chapter five, I found that there were species-specific differences in sedimentation rate and variability in Tillamook Bay, OR. Schoenoplectus pungens was found to retain more sediment than C. lyngbyei. Sedimentation rate was observed to be variable by location within the estuary. Two patterns of sediment accumulation were observed. The first occurred along vegetation gradients, with increased sedimentation farther into vegetation beds. In the second pattern, sediment accumulation was observed to be greatest at the marsh/mudflat boundary where vegetation was dense and then decreased with increasing depth into the vegetation. In conclusion, this dissertation explores the interaction of emergent wetland vegetation with environmental factors. Image analysis provides a new tool for rapid characterization of vegetation structure, a burial experiment documents Schoenoplectus pungens’ tolerance to sand burial, a field study at Tillamook, OR documents the relationship between sediment accumulation and emergent vegetation beds, and a wetland classification is developed for coastal wetlands along the Great Lakes, which includes plant communities dominated by S. pungens. Close

• 207. [Article] Hydrologic and Land Cover Effects on Sources and Fate of In-Stream Fluorescent Dissolved Organic Matter

  Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM ...

  Citation × Citation Citation Abstract Copy Title: Hydrologic and Land Cover Effects on Sources and Fate of In-Stream Fluorescent Dissolved Organic Matter Author: Lee, Baek Soo P. Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM compositions in catchments of the western U.S. are poorly understood. UV and fluorescent spectroscopy is a simpler, faster, and less expensive DOM fingerprinting technique compared to techniques, such as nuclear magnetic resonance (NMR) spectroscopy or wet chemical fractionation, and could be useful for characterizing complex DOM chemistry. However, only 1 % of DOM is estimated to be fluorescent, and the utility of UV and fluorescent spectroscopy for DOM characterization needs to be further investigated. This dissertation applied UV and fluorescent spectroscopy to examine hydrologic and land cover controls on DOM chemistry in streams of 45 catchments in the forested headwaters and a mixed landscape of the Willamette River Basin, Oregon, based on two years of monitoring. This dissertation contributes three major findings. First, freezing of water alters DOM chemistry by preferentially precipitating aromatic DOM. Second, UV and fluorescent spectroscopy was able to discriminate DOM delivered from highly processed, proteinrich deep subsurface sources during dry seasons especially in forested headwater streams of the H. J. Andrews Experimental Forest (HJA), where nitrogen inputs are very low. In addition, fluorescent DOM chemistry differed among watersheds with varying forest management history. Third, although fluorescent DOM in a headwater forested system differed among land use history, fluorescent DOM composition did not vary among streams draining a well-mixed landscape of urban, pasture/hay, forest, and agricultural land cover types in the central Willamette River Basin, where nitrogen inputs to streams are relatively high. Dissolved organic carbon (DOC) concentration decreased and the fluorescent index indicated an increase in terrestrial sources of DOM from small (1st and 2nd order) to large (4th to 6th order) streams. A protein-like DOM component that was detected in the headwater forested study site (HJA) was not detected in stream samples from the middle basin study site. These findings indicate that in-stream respiration, fueled by nutrient additions from agriculture runoff, consumes bioavailable, labile DOM (proteins) preferentially relative to more recalcitrant, terrestrial sources of DOM along water flow paths from headwater streams to major rivers. This study shows the clear applicability of the fluorescent characterization of DOM in identifying hydrologic and landscape controls as well as varying DOM chemistry and functions throughout watershed ecosystems. Title: Hydrologic and Land Cover Effects on Sources and Fate of In-Stream Fluorescent Dissolved Organic Matter Author: Lee, Baek Soo P. Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM compositions in catchments of the western U.S. are poorly understood. UV and fluorescent spectroscopy is a simpler, faster, and less expensive DOM fingerprinting technique compared to techniques, such as nuclear magnetic resonance (NMR) spectroscopy or wet chemical fractionation, and could be useful for characterizing complex DOM chemistry. However, only 1 % of DOM is estimated to be fluorescent, and the utility of UV and fluorescent spectroscopy for DOM characterization needs to be further investigated. This dissertation applied UV and fluorescent spectroscopy to examine hydrologic and land cover controls on DOM chemistry in streams of 45 catchments in the forested headwaters and a mixed landscape of the Willamette River Basin, Oregon, based on two years of monitoring. This dissertation contributes three major findings. First, freezing of water alters DOM chemistry by preferentially precipitating aromatic DOM. Second, UV and fluorescent spectroscopy was able to discriminate DOM delivered from highly processed, proteinrich deep subsurface sources during dry seasons especially in forested headwater streams of the H. J. Andrews Experimental Forest (HJA), where nitrogen inputs are very low. In addition, fluorescent DOM chemistry differed among watersheds with varying forest management history. Third, although fluorescent DOM in a headwater forested system differed among land use history, fluorescent DOM composition did not vary among streams draining a well-mixed landscape of urban, pasture/hay, forest, and agricultural land cover types in the central Willamette River Basin, where nitrogen inputs to streams are relatively high. Dissolved organic carbon (DOC) concentration decreased and the fluorescent index indicated an increase in terrestrial sources of DOM from small (1st and 2nd order) to large (4th to 6th order) streams. A protein-like DOM component that was detected in the headwater forested study site (HJA) was not detected in stream samples from the middle basin study site. These findings indicate that in-stream respiration, fueled by nutrient additions from agriculture runoff, consumes bioavailable, labile DOM (proteins) preferentially relative to more recalcitrant, terrestrial sources of DOM along water flow paths from headwater streams to major rivers. This study shows the clear applicability of the fluorescent characterization of DOM in identifying hydrologic and landscape controls as well as varying DOM chemistry and functions throughout watershed ecosystems. Close

• 208. [Article] Spatial variability of African dust in soils in a montane tropical landscape in Puerto Rico

  Access to this item has been restricted by repository administrators at the request of the publisher, Elsevier, until July 23, 2017.

  Citation × Citation Citation Abstract Copy Title: Spatial variability of African dust in soils in a montane tropical landscape in Puerto Rico Author: McClintock, M. A., Porder, S., Brocard, G., Willenbring, J., Pett-Ridge, J. C., Tamayo, C. Access to this item has been restricted by repository administrators at the request of the publisher, Elsevier, until July 23, 2017. Title: Spatial variability of African dust in soils in a montane tropical landscape in Puerto Rico Author: McClintock, M. A., Porder, S., Brocard, G., Willenbring, J., Pett-Ridge, J. C., Tamayo, C. Access to this item has been restricted by repository administrators at the request of the publisher, Elsevier, until July 23, 2017. Close

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

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

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

• 210. [Article] Constraining surface carbon fluxes using in situ measurements of carbonyl sulfide and carbon dioxide

  This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291944-9224.

  Citation × Citation Citation Abstract Copy Title: Constraining surface carbon fluxes using in situ measurements of carbonyl sulfide and carbon dioxide Author: Yakir, D., Gupta, M., Berkelhammer, M., Noone, D., Montzka, S., Chen, H., Asaf, D., Still, C., Provencal, R. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291944-9224. Title: Constraining surface carbon fluxes using in situ measurements of carbonyl sulfide and carbon dioxide Author: Yakir, D., Gupta, M., Berkelhammer, M., Noone, D., Montzka, S., Chen, H., Asaf, D., Still, C., Provencal, R. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291944-9224. Close