Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): Evaluate how warming and increasing atmospheric CO2 concentration affect the structure and functioning of Great Plains grasslands through their affects on primary production, N and C cycling, water relations, and plant community dynamics. Approach (from AD-416): Stable Isoptope Lab/University of Wyoming (SILUW) and ARS will collaborate in planning and conducting cooperative global change research at the High Plains Grasslands Research Station (HPGRS) to investigate how global change influences ecosystem functioning through evaluating the combined effects of rising atmospheric CO2 and temperature on C and N cycling, plant/soil water relations, weed invasions and plant community ecology. Research will be conducted under realistic field conditions in a native, semi-arid grassland in which ambient CO2 is increased from present-day levels of 390 ppm to 600 ppm and temperatures increased 1.5/3 C day/night. These altered environmental conditions are predicted to develop in Wyoming over the second half of the century. Collaborators at the University of Wyoming are working with ARS to increase our understanding of how plants and soils respond to global warming, rising atmospheric carbon dioxide (CO2), and altered precipitation, as part of a comprehensive research project predicting how western rangelands will respond to climate change. We are in the 8th year of the Prairie Heating and CO2 Enrichment (PHACE) experiment, being conducted at the USDA-ARS High Plains Grassland Research Station in Cheyenne, WY. Research through this cooperative agreement on the PHACE experiment focused on obtaining a more thorough understanding of below- ground global change responses through extensive sampling during the final growing season of the experiment. New sub-studies included effects of elevated CO2 and warming on 1) root architecture and chemistry of key rangeland species; 2) microbial carbon use efficiency and effects on nitrogen availability; rhizosphere N fixation; root crown biomass and chemistry; soil nematodes; and mycorrhizae. This work complements ongoing studies at PHACE to determine how elevated CO2 and warming influence the cycling of key resources: water, nitrogen and carbon. In addition, a sub- experiment started in FY 2012, to examine success of restoration under different climate conditions was continued. The work follows emergence and establishment of grass and forb species of different biogeographic origins across the northern and southern mixed-grass prairies in North America. Three graduate students are contributing to this research. The PHACE experimental treatments will be terminated in September 2013. Above and below ground biomass and soils will be harvested for analysis and disturbed plots will be restored. To ensure accountability of funds utilized, the ADODR and his staff hold meetings every 6 months with collaborators to discuss research and site issues; staff of both groups communicates regularly on experimental protocols, site management, and presentation of results. The group continues to coordinate on modeling and data base management efforts so the results of this work can be extrapolated by modeling projects involving project scientists and potential future collaborators.
Impacts
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Publications
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): Evaluate how warming and increasing atmospheric CO2 concentration affect the structure and functioning of Great Plains grasslands through their affects on primary production, N and C cycling, water relations, and plant community dynamics. Approach (from AD-416): Stable Isoptope Lab/University of Wyoming (SILUW) and ARS will collaborate in planning and conducting cooperative global change research at the High Plains Grasslands Research Station (HPGRS) to investigate how global change influences ecosystem functioning through evaluating the combined effects of rising atmospheric CO2 and temperature on C and N cycling, plant/soil water relations, weed invasions and plant community ecology. Research will be conducted under realistic field conditions in a native, semi-arid grassland in which ambient CO2 is increased from present-day levels of 390 ppm to 600 ppm and temperatures increased 1.5/3 C day/night. These altered environmental conditions are predicted to develop in Wyoming over the second half of the century. Collaborators at the University of Wyoming are working with ARS to increase our understanding of how plants and soils respond to global warming, rising atmospheric carbon dioxide (CO2), and altered precipitation, as part of a comprehensive research project predicting how western rangelands will respond to climate change. We are in the 7th year of the Prairie Heating and CO2 Enrichment (PHACE) experiment, being conducted at the USDA-ARS High Plains Grassland Research Station in Cheyenne, WY. Research through this cooperative agreement on the PHACE experiment focused on three major elements: 1) leaf carbon metabolism; 2) ecosystem scale CO2 and H2O exchange; and 3) plant community restoration. Light- and dark-acclimated leaf respiration for the dominant perennial grass, western wheatgrass (Pascopyrum smithii), was determined. These measurements provide important mechanistic information about how climate change influences carbon exchange in semiarid rangelands. The measurements complement ongoing studies at PHACE examining ecosystem scale respiration and photosynthesis. In addition, efforts continue to monitor CO2 exchange at the plot level to examine how climate change impacts net carbon uptake. A new subexperiment was implemented within PHACE plots to examine success of restoration under different climate conditions. The work follows emergence and establishment of grass and forb species of different biogeographic origins across the northern and southern mixed-grass prairies in North America. Three graduate students are contributing to this research. The PHACE experimental treatments will be terminated in September 2013. Above and below ground biomass and soils will be harvested for analysis and disturbed plots will be restored. To ensure accountability of funds utilized, the ADODR and his staff hold meetings every 6 months with collaborators to discuss research and site issues; staff of both groups communicates regularly on experimental protocols, site management, and presentation of results. The group continues to coordinate on modeling and data base management efforts so the results of this work can be extrapolated by modeling projects involving project scientists and potential future collaborators.
Impacts
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Publications
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) Evaluate how warming and increasing atmospheric CO2 concentration affect the structure and functioning of Great Plains grasslands through their affects on primary production, N and C cycling, water relations, and plant community dynamics. Approach (from AD-416) Stable Isoptope Lab/University of Wyoming (SILUW) and ARS will collaborate in planning and conducting cooperative global change research at the High Plains Grasslands Research Station (HPGRS) to investigate how global change influences ecosystem functioning through evaluating the combined effects of rising atmospheric CO2 and temperature on C and N cycling, plant/soil water relations, weed invasions and plant community ecology. Research will be conducted under realistic field conditions in a native, semi-arid grassland in which ambient CO2 is increased from present-day levels of 390 ppm to 600 ppm and temperatures increased 1.5/3 C day/night. These altered environmental conditions are predicted to develop in Wyoming over the second half of the century. University of Wyoming collaborators are working with ARS to increase our understanding of how soils and plants respond to global warming, rising CO2, and altered precipitation, as part of a comprehensive research project predicting how western rangelands will respond to climate change. We are in the 6th year of the Prairie Heating and CO2 Enrichment (PHACE) experiment. Work on the PHACE project led by the UW research teams continues to evolve and expand. UW collaborator submitted two large research proposals to continue below ground studies on C and N dynamics, and both have been recommended for funding. The NSF-Ecosystems grant started in Sept., 2010, and examines plant-microbe feedback mechanisms related to C and N cycling. The DOE-TCP grant is expected to start by October, 2011, and provides funding for continuation of the experimental treatments through the summer of 2013, in addition to modeling. A proposal by UW collaborator and his postdoc was recommended for funding by the UW NASA Space Grant Consortium to begin examining how plant invasion alters ecosystem water and carbon exchange. The University of Wyoming Stable Isotope Facility (UWSIF) will continue to provide expertise and analyses for the PHACE project. In addition to continuing work on C cycling in native mixed-grass prairie using stable isotopes at PHACE, a UW collaborator's group has expanded their research questions to the role of invasive species in mediating C and N cycling by measuring net ecosystem exchange (NEE), evapotranspiration (ET) and soil biogeochemical processes within the �weeds� portion of the PHACE experiment. Additional, species-specific experiments have been conducted outside the PHACE plots using stable isotope tracer techniques. The Williams Rangeland Plant Ecophysiology Lab (RPEL) at UW continues to contribute to the PHACE project with studies on leaf to whole plant photosynthetic and water relations responses and N uptake patterns and by supporting NEE and ET measurements led by a UW collaborator�s group and focusing on leaf photosynthetic biochemistry, leaf gas exchange, plant water relations, leaf isotopic discrimination analysis and N uptake and utilization patterns in an effort to characterize plant responses to warming, CO2 enrichment and experimental irrigation, and to upscale leaf gas exchange to the ecosystem level. New studies are planned in the final three years of this experiment to evaluate how global change treatments effect plant respiration as well as studies on longterm stomatal responses to CO2 warming. The ADODR holds meetings every 6 months with UW collaborators to discuss research and site issues. Staff of both groups communicate regularly on experimental protocols, site management, and presentation of results. The group continues to coordinate on modeling and data base management efforts so the results of this work can be extrapolated by modeling projects involving project scientists and potential future collaborators.
Impacts
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Publications
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) Evaluate how warming and increasing atmospheric CO2 concentration affect the structure and functioning of Great Plains grasslands through their affects on primary production, N and C cycling, water relations, and plant community dynamics. Approach (from AD-416) Stable Isoptope Lab/University of Wyoming (SILUW) and ARS will collaborate in planning and conducting cooperative global change research at the High Plains Grasslands Research Station (HPGRS) to investigate how global change influences ecosystem functioning through evaluating the combined effects of rising atmospheric CO2 and temperature on C and N cycling, plant/soil water relations, weed invasions and plant community ecology. Research will be conducted under realistic field conditions in a native, semi-arid grassland in which ambient CO2 is increased from present-day levels of 390 ppm to 600 ppm and temperatures increased 1.5/3 C day/night. These altered environmental conditions are predicted to develop in Wyoming over the second half of the century. Collaborating UW scientists are working with ARS to increase our understanding of how soils and plants respond to global warming, rising CO2, and altered precipitation, as part of a comprehensive research project predicting how western rangelands will respond to climate change. We are midway through the Prairie Heating and CO2 Enrichment (PHACE) experiment. Work on the PHACE project led by the UW research teams is progressing rapidly. The collaborative engagement between two UW research groups on this project continues to evolve and expand. One UW scientist submitted two large research proposals to continue below ground studies on C and N dynamics, and one, the NSF ETBC proposal has been recommended for funding. A proposal by a UW scientist and his postdoc was recommended for funding by the UW NASA Space Grant Consortium to begin examining how plant invasion alters ecosystem water and carbon exchange. The University of Wyoming Stable Isotope Facility (UWSIF) will continue to provide expertise and analyses for the PHACE project; technical difficulties in analyzing high 15N enrichment values for PHACE samples have been remedied. Research activities by the UW teams for the PHACE project during the period from October 2009 to present involved 4 undergraduate technicians, 3 graduate students, 2 postdocs and 2 senior faculty scientists. In addition to continuing work on carbon cycling using stable isotopes at PHACE, a UW scientist group conducted a growth chamber experiment to test the role of mycorrhizae in affecting nutrient uptake under elevated CO2. This experiment involved development of new infrastructure at the Crops Lab in Fort Collins to provide isotopic labeling of both ambient and elevated CO2 conditions. Additionally, new 15N labeling techniques were developed. Preliminary results from this project are forthcoming. Another UW scientist's Rangeland Plant Ecophysiology Lab (RPEL) at UW continues to contribute to the PHACE project with studies on leaf to whole plant photosynthetic and water relations responses and N uptake patterns and by supporting NEE and ET measurements. A UW lab's work focuses on leaf photosynthetic biochemistry, leaf gas exchange, plant water relations, leaf isotopic discrimination analysis and N uptake and utilization patterns, all in an effort to characterize plant responses to warming, CO2 enrichment and experimental irrigation, as well as to upscale leaf gas exchange to the ecosystem level. With leveraging from the University of Wyoming Stable Isotope Facility, the another UW lab has led studies on leaf carbon isotope discrimination. To ensure accountability of funds utilized, the ADODR and his staff hold meetings every 6 months with UW collaborators to discuss research and site issues; staff of both groups communicates regularly on experimental protocols, site management, and presentation of results.
Impacts
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