Search

Search Results

• 1. [Article] SmithRobertJ2017.pdf

  Citation × Citation Citation Abstract Copy Title: SmithRobertJ2017.pdf Author: Smith, Robert J. Title: SmithRobertJ2017.pdf Author: Smith, Robert J. Close

• 2. [Article] SmithRobertJ_DataAndCode.zip

  Citation × Citation Citation Abstract Copy Title: SmithRobertJ_DataAndCode.zip Author: Smith, Robert J. Title: SmithRobertJ_DataAndCode.zip Author: Smith, Robert J. Close

• 3. [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

• 4. [Article] A simple tool for estimating throughfall nitrogen deposition in forests of western North America using lichens

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: A simple tool for estimating throughfall nitrogen deposition in forests of western North America using lichens Author: Ahuja, Suraj, Fenn, Mark E., Berryman, Shanti, Hutten, Martin A., McMurray, Jill A., Schirokauer, David, Root, Heather T., Jovan, Sarah, Geiser, Linda H., Dillman, Karen To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Title: A simple tool for estimating throughfall nitrogen deposition in forests of western North America using lichens Author: Ahuja, Suraj, Fenn, Mark E., Berryman, Shanti, Hutten, Martin A., McMurray, Jill A., Schirokauer, David, Root, Heather T., Jovan, Sarah, Geiser, Linda H., Dillman, Karen To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Close

• 5. [Article] Lichen Functional Trait Variation Along an East-West Climatic Gradient in Oregon and Among Habitats in Katmai National Park, Alaska

  Functional traits of vascular plants have been an important component of ecological studies for a number of years; however, in more recent times vascular plant ecologists have begun to formalize a set ...

  Citation × Citation Citation Abstract Copy Title: Lichen Functional Trait Variation Along an East-West Climatic Gradient in Oregon and Among Habitats in Katmai National Park, Alaska Author: Spickerman, Kaleigh Functional traits of vascular plants have been an important component of ecological studies for a number of years; however, in more recent times vascular plant ecologists have begun to formalize a set of key traits and universal system of trait measurement. Many recent studies hypothesize global generality of trait patterns, which would allow for comparison among ecosystems and biomes and provide a foundation for general rules and theories, the so-called “Holy Grail” of ecology. However, the majority of these studies focus on functional trait patterns of vascular plants, with a minority examining the patterns of cryptograms such as lichens. Lichens are an important component of many ecosystems due to their contributions to biodiversity and their key ecosystem services, such as contributions to mineral and hydrological cycles and ecosystem food webs. Lichens are also of special interest because of their reliance on atmospheric deposition for nutrients and water, which makes them particularly sensitive to air pollution. Therefore, they are often used as bioindicators of air pollution, climate change, and general ecosystem health. This thesis examines the functional trait patterns of lichens in two contrasting regions with fundamentally different kinds of data. To better understand the patterns of lichen functional traits, we examined reproductive, morphological, and chemical trait variation along precipitation and temperature gradients in Oregon. Specifically, we measured traits of 102 macrolichen species collected from 166 USDA Forest Service program for Forest Inventory and Analysis (FIA) plots. These plots were located in a more-or-less continuous swath across Oregon between 43°W and 45°W. Plots were grouped into seven regions (the Oregon Coast, Coast Range, Willamette Valley, Western Cascades, High Cascades, Eastern Cascades, and Eastern Oregon). Using multivariate analysis techniques we found strong linear and nonlinear trait patterns along precipitation and temperature gradients, and were able to characterize the seven main regions of Oregon by the relative abundance of lichen traits. The literature on what lichen traits are most common in which habitats is sparse and anecdotal; understanding trait-habitat patterns could have management implications due to lichen importance as bioindicators and animal forage. Understanding how key traits are distributed among habitats could provide insight into potential air pollution impacts on certain habitats, animal movement among habitats, etc. To examine trait-habitat patterns, we measured the reproductive, morphological, and chemical traits of 429 lichen species collected haphazardly (without a formal sampling framework) from ten distinct habitats within Katmai National Park in southwest Alaska as part of a taxonomic inventory. Using multivariate analysis techniques we grouped habitats based on the expression of lichen traits and described the relative abundance of each trait in different habitats. The second goal of this study was to examine the potential usefulness of herbarium collections in ecological studies of this type. Herbarium specimens are a large potential resource that is generally unused in ecological studies due to concerns over potential bias and noise introduced by variation in collection methods. However, recent work has suggested that herbarium specimens may yield more useful results than previously thought and could be a valid resource for ecological studies. The data for our study were collected in a haphazard manner for a floristic inventory, similar to the collection methods used for many herbarium specimens. The patterns that we observed indicates that herbarium specimens may be a good resource for future research. Title: Lichen Functional Trait Variation Along an East-West Climatic Gradient in Oregon and Among Habitats in Katmai National Park, Alaska Author: Spickerman, Kaleigh Functional traits of vascular plants have been an important component of ecological studies for a number of years; however, in more recent times vascular plant ecologists have begun to formalize a set of key traits and universal system of trait measurement. Many recent studies hypothesize global generality of trait patterns, which would allow for comparison among ecosystems and biomes and provide a foundation for general rules and theories, the so-called “Holy Grail” of ecology. However, the majority of these studies focus on functional trait patterns of vascular plants, with a minority examining the patterns of cryptograms such as lichens. Lichens are an important component of many ecosystems due to their contributions to biodiversity and their key ecosystem services, such as contributions to mineral and hydrological cycles and ecosystem food webs. Lichens are also of special interest because of their reliance on atmospheric deposition for nutrients and water, which makes them particularly sensitive to air pollution. Therefore, they are often used as bioindicators of air pollution, climate change, and general ecosystem health. This thesis examines the functional trait patterns of lichens in two contrasting regions with fundamentally different kinds of data. To better understand the patterns of lichen functional traits, we examined reproductive, morphological, and chemical trait variation along precipitation and temperature gradients in Oregon. Specifically, we measured traits of 102 macrolichen species collected from 166 USDA Forest Service program for Forest Inventory and Analysis (FIA) plots. These plots were located in a more-or-less continuous swath across Oregon between 43°W and 45°W. Plots were grouped into seven regions (the Oregon Coast, Coast Range, Willamette Valley, Western Cascades, High Cascades, Eastern Cascades, and Eastern Oregon). Using multivariate analysis techniques we found strong linear and nonlinear trait patterns along precipitation and temperature gradients, and were able to characterize the seven main regions of Oregon by the relative abundance of lichen traits. The literature on what lichen traits are most common in which habitats is sparse and anecdotal; understanding trait-habitat patterns could have management implications due to lichen importance as bioindicators and animal forage. Understanding how key traits are distributed among habitats could provide insight into potential air pollution impacts on certain habitats, animal movement among habitats, etc. To examine trait-habitat patterns, we measured the reproductive, morphological, and chemical traits of 429 lichen species collected haphazardly (without a formal sampling framework) from ten distinct habitats within Katmai National Park in southwest Alaska as part of a taxonomic inventory. Using multivariate analysis techniques we grouped habitats based on the expression of lichen traits and described the relative abundance of each trait in different habitats. The second goal of this study was to examine the potential usefulness of herbarium collections in ecological studies of this type. Herbarium specimens are a large potential resource that is generally unused in ecological studies due to concerns over potential bias and noise introduced by variation in collection methods. However, recent work has suggested that herbarium specimens may yield more useful results than previously thought and could be a valid resource for ecological studies. The data for our study were collected in a haphazard manner for a floristic inventory, similar to the collection methods used for many herbarium specimens. The patterns that we observed indicates that herbarium specimens may be a good resource for future research. Close