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• 1. [Article] Soil-Climate Feedbacks: Understanding the Controls and Ecosystem Responses of the Carbon Cycle Under a Changing Climate

  Soil organic matter (SOM) decomposition and formation is an important climate feedback, with the potential to amplify or offset climate forcing. To understand the fate of soil carbon (C) stores and fluxes ...

  Citation × Citation Citation Abstract Copy Title: Soil-Climate Feedbacks: Understanding the Controls and Ecosystem Responses of the Carbon Cycle Under a Changing Climate Author: Reynolds, Lorien Year: 2016 Soil organic matter (SOM) decomposition and formation is an important climate feedback, with the potential to amplify or offset climate forcing. To understand the fate of soil carbon (C) stores and fluxes (i.e., soil respiration) under future climate it is necessary to investigate responses across spatial and temporal scales, from the ecosystem to the molecular level, from diurnal to decadal trends. Moreover, it is important to question the assumptions and paradigms that underlie apparently paradoxical evidence to reveal the true nature of soil-climate feedbacks. My dissertation includes research into the response of soil respiration in Pacific Northwest prairies to warming and wetting along a natural regional climate gradient (Chapter II), and then delves deeper into the mechanisms underlying SOM decomposition and formation, examining the temperature sensitivity of SOM decomposition of prairie soils that were experimentally warmed for ~2 yr, and a forest soil in which litter-inputs were manipulation for 20 yr (Chapter III), and finally testing soil C cycling dynamics, including mineral-associated C pools, decomposition dynamics, and the molecular nature of SOM itself, under litter-manipulation in order to understand the controls on SOM formation and mineralization (Chapter IV). This dissertation includes previously published and unpublished coauthored material; see the individual chapters for a list of co-authors, and description of contributions. Title: Soil-Climate Feedbacks: Understanding the Controls and Ecosystem Responses of the Carbon Cycle Under a Changing Climate Author: Reynolds, Lorien Year: 2016 Soil organic matter (SOM) decomposition and formation is an important climate feedback, with the potential to amplify or offset climate forcing. To understand the fate of soil carbon (C) stores and fluxes (i.e., soil respiration) under future climate it is necessary to investigate responses across spatial and temporal scales, from the ecosystem to the molecular level, from diurnal to decadal trends. Moreover, it is important to question the assumptions and paradigms that underlie apparently paradoxical evidence to reveal the true nature of soil-climate feedbacks. My dissertation includes research into the response of soil respiration in Pacific Northwest prairies to warming and wetting along a natural regional climate gradient (Chapter II), and then delves deeper into the mechanisms underlying SOM decomposition and formation, examining the temperature sensitivity of SOM decomposition of prairie soils that were experimentally warmed for ~2 yr, and a forest soil in which litter-inputs were manipulation for 20 yr (Chapter III), and finally testing soil C cycling dynamics, including mineral-associated C pools, decomposition dynamics, and the molecular nature of SOM itself, under litter-manipulation in order to understand the controls on SOM formation and mineralization (Chapter IV). This dissertation includes previously published and unpublished coauthored material; see the individual chapters for a list of co-authors, and description of contributions. Close

• 2. [Article] The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies

  To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial ...

  Citation × Citation Citation Abstract Copy Title: The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies Author: Hendricks, Lauren Year: 2016 To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial forb species native to Pacific Northwest prairies: Ranunculus austro-oreganus, Sidalcea malviflora spp. virgata, Microseris laciniata, and Eriophyllum lanatum. These populations were distributed along a 700 kilometer latitudinal gradient from southern Oregon to Whidbey Island, Washington. We found significant differences in plant size and reproduction among populations for all species, but correlations among edaphic and climate variables and plant size and reproduction were weak. Instead, density was more strongly correlated with both edaphic and climate variables, suggesting that this is a better indicator of long-term demographic processes. Although a few factors are important across species (e.g., nutrient availability and minimum temperature), response is idiosyncratic at the individual species level in Pacific Northwest prairies. Title: The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies Author: Hendricks, Lauren Year: 2016 To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial forb species native to Pacific Northwest prairies: Ranunculus austro-oreganus, Sidalcea malviflora spp. virgata, Microseris laciniata, and Eriophyllum lanatum. These populations were distributed along a 700 kilometer latitudinal gradient from southern Oregon to Whidbey Island, Washington. We found significant differences in plant size and reproduction among populations for all species, but correlations among edaphic and climate variables and plant size and reproduction were weak. Instead, density was more strongly correlated with both edaphic and climate variables, suggesting that this is a better indicator of long-term demographic processes. Although a few factors are important across species (e.g., nutrient availability and minimum temperature), response is idiosyncratic at the individual species level in Pacific Northwest prairies. Close