Stephen Thomas Jackson - US grants

Abstract ATM-9729090 Jackson, Stephen T. University of Wyoming Title: Isotopic Composition of Aquatic-Plant Tissues as Paleoclimate Proxies The SGER award supports a pilot study on isotopic composition of aquatic plant tissues as a paleoclimate proxy. The project is aimed at developing, testing, and applying a new and untried approach for inferring precipitation seasonality, moisture source, and evaporation loss from small, freshwater lakes. The work will test a mass balance approach to determine whether it can successfully disentangle evaporation and precipitation signals from lakewater data. Stable isotopes will be studied from modern lakewater, aquatic-plant seeds, lake sediments, and precipitation from sites distributed over a wide area in the central and southern Rocky Mountains and the Colorado Plateau. If successful, this method should open the way for a variety of applications in paleoclimate inference and model testing.

9806574
Jackson

Local and regional expansion of native species due to migration, climate change or land use offer additional opportunities to study patterns and effects of invasion. Ongoing, natural invasions provide model systems to forecast biotic movements and consequences as climate and land use change in the future. This grant will use paleoecological and ecological methods to study the ongoing invasion of Utah juniper (Juniperus osteosperma) in central and eastern Wyoming and adjacent Montana, initiated when Utah juniper crossed the Rocky Mountains and the Continental Divide during the late Holocene. This invasion can be showcased as a model system for addressing central issues about natural invasions because: (1) it is ongoing and has been proceeding for at least 2000 years, long enough to encompass both long and short-distance dispersal events as well as population infilling at older sites; (2) it can be documented at unprecedented spatiotemporal resolution using fossil woodrat-middens, tree-ring based demographic analyses, and both ground and aerial repeat photography; (3) it has the potential to generate important hypotheses as well as provide diverse opportunities to study population dynamics, genetic consequences, and ecosystem effects across a chronosequence of sites representing different stages of invasion, and (4) it underscores the value of historical evidence in reexamining current paradigms about tree invasions in rangelands.

A stable isotope ratio mass spectrometer facility is proposed at the University of Wyoming to address several multidisciplinary processes including carbon flux between ecosystems and the atmosphere, ecosystem responses to simulated climate change, patterns of precipitation isotopic chemistry, reconstruction of climates using proxy records, and the geochemistry of environmental contamination. At present, no such facility exists in the state of Wyoming. This proposal funds the purchase of a dual inlet isotope ration mass spectrometer for high precision analysis of the stable isotopes of H, C, N, S, and O in air, water, soil, and vegetation. This instrument will support numerous ongoing studies that utilize stable isotope analyses to enhance a basic understanding of terrestrial processes. These include: 1) delineating the CO2 source and sink activity of native and agricultural ecosystems; 2) quantifying the degree to which changes in snow depth alter the patterns of water sources used by plants and modifies the flux of carbon; 3) assessing the weekly patterns of the isotopic composition of precipitation from an array of sites across the U.S; 4) applying the isotopic composition of plant tissues as paleoclimate proxies; 5) using stable isotopes to identify sources and processes affecting groundwater contaminants such as nitrate and hazardous organic compounds; and 6) characterizing the seasonal foraging patterns of free-ranging ungulates and applying this to the reconstruction of anthropological diets and predation strategies. The major focus of the proposed facility will be to nurture an expansion of interdisciplinary collaboration among diverse research teams. In addition, this instrumentation will provide regular exposure and research training opportunities for upper division undergraduates, graduate students, and postdoctoral scientists while encouraging other researchers on campus to utilize stable isotopes as part of their research. Finally, the facility will perform analyses that will contribute to several new national and international research initiatives, including a U.S. contribution to the Global Network of Isotopes in Precipitation (GNIP) and the Biosphere-Atmosphere Stable Isotope Network (BASIN).

This project explores the role of centennial to millennial-scale climate variability, particularly wet and dry extremes, in governing the tempo, rate, and spatial pattern of invasion and expansion of three economically and ecologically important tree species (yellow birch, hemlock, beech) near their northwestern range limits in the western Great Lakes region. Geographic ranges and population sizes of these species have expanded episodically in the last 5000 years, and preliminary evidence indicates that these expansions were paced by climate variability. We will use paleoecological methods (analysis of pollen, macrofossils, and stomates from lake and peatland sediments) to delineate the spatial and temporal patterns of these expansions, and paleoclimatological methods (analyses of paleontological and geochemical indicators from peatland sediments) to develop detailed, independent records of spatial and temporal patterns of climate variability. Comparison of the paleoecological and paleoclimatological data will link the ecological responses to climate variations across a range of timescales. Understanding ecological and climatic dynamics of the past will contribute to our ability to predict ecological responses to ongoing and future climatic change.

This award funds a project to investigate the utility of peatland in eastern North America as archives of climate information. The researchers will conduct multi-proxy paleoclimate studies in peatland areas located in the Canadian Maritime provinces, northern Minnesota, and southwest Ontario. Stable isotope studies will examine the unique hydrology of ombrotrophic peatlands and further understand late Holocene climate variability based on tree-rings and pollen. Most tree-ring records from the region extend only a few centuries and pollen sequences record responses to climate change but often lag and/or mask abrupt changes. The researchers aim to develop high-resolution and climate-sensitive datasets from peatlands to document climate variability during the past 3,000 years in the region.

The research will help quantify regional responses of forest ecosystems to climate change and support interdisciplinary training for a post-doctoral researcher and several undergraduate students.

Proposal: EPS-0447681

Proposal Title: Wyoming NSF EPSCoR Research Infrastructure
Improvement

Institution: University of Wyoming

The Wyoming EPSCoR Research Infrastructure Improvement award will build capacity and capability for national competitiveness in Natural Resource Sciences, especially emphasizing ecological topology of different spatial and time scales as it relates to ecosystem and global change: Currently, the university has 20 faculty members in diverse departments for this very broad, interdisciplinary area. The award will provide partial start-up support for five new hires to fill specific needed niches in a newly initiated interdisciplinary PhD program. Equipment and committed technical staff will be supported to enhance the Stable Isotope, Nucleic Acid Exploration, and GIS facilities, thereby strengthening research competitiveness and fostering additional collaborations in this research focus area and contributing to the development of a critical mass of research and educational expertise necessary for large, multi-investigator, competitive research programs. This focus relating to ecosystem responses to global change has significant current merit and importance both for Wyoming and, more broadly, for national and international concerns. There is growing recognition of the need for modeling and understanding ecological processes at different spatial scales. This project will provide a research and education focus related to that need for the university. More importantly, Wyoming's strength in geological studies will give added value in being able to address questions in different time scales as well as spatial scales. This perspective will be of particular value in informing policy decisions.

Integration of research and education will be emphasized in all aspects of the project. In the faculty recruitments researchers who are also excellent teachers will be sought to strengthen the new interdisciplinary PhD program. The award will supplement the university's level of graduate student stipends and this greater level of support will require that participating students take a course in Teaching for Scientists and Engineers. A different kind of graduate student support is to be provided for graduate student mentors for the Science Education program. Students receiving this mentorship support will assist secondary science education students in a summer research experience. Undergraduate fellowships for university and community college students will engage these students in research experiences. Outreach efforts will expand the number of high students participating in a previously successful summer research program. In addition, technical assistance will be engaged for efforts to increase public awareness of the role of research in higher education and its contribution to the state's economic growth and especially to make high school students and their parents more aware of undergraduate research opportunities.

In the eastern United States, forest plant communities that were present 17,000 to 12,000 years ago are no longer represented on the landscape. This project will determine whether these historic assemblages of vegetation arose from: 1) unusually high temperature seasonality, 2) low atmospheric carbon dioxide concentrations, and/or 3) herbivory by now-extinct ''''megafauna'''' (e.g. mammoths, mastodons). This project integrates paleoecological data and mechanistic vegetation models. Specifically, this project will study lake-sediment cores from seven mid-continental sites from Tennessee to Minnesota and model climatic and carbon dioxide controls on vegetation composition. Sediments will be analyzed to infer ecological histories of vegetation, fire, and megafaunal population density and determine the timing of key ecological events.

This study of past environmental change has direct implications for current climate-change concerns. In particular, for planning purposes, there is an urgent need for accurate ecological forecasts, but the robustness of current ecological models, when applied to environmental conditions outside the range of modern observations, is poorly understood. Moreover, climates at the end of the 21st century will likely include combinations of temperature and precipitation unlike any observed today. The well-documented anomalous late-glacial climates and ecological communities are a good testing ground for evaluating the adequacy of current models of ecological response to complex environmental change. This work will support student training and outreach activities for high school teachers and students.

Sediments of Sphagnum-dominated peatlands constitute a valuable archive of Holocene climate change and variability. These peatlands are broadly distributed at mid to high latitudes in both the Northern and Southern Hemispheres, and at high elevations at lower latitudes, including tropical mountains. Their sediments contain a variety of microfossil, macrofossil, geochemical, and stable-isotope proxies of temperature and hydrology, and records are demonstrably sensitive to subcentennial to subdecadal climate variation.

This grant supports an international workshop to take place in May 2009, assembling 36 leading researchers to identify critical research needs and priorities, develop a comprehensive science agenda to advance peatland paleoclimatology, and initiate planning for a global network of Holocene peatland records. Participants will include scientists with expertise in peatland paleoclimatology, hydrology, and biogeochemistry, as well as paleoclimatologists with expertise in modeling, and statistical analysis, and other late Holocene archives (e.g., tree rings, speleothems, lake sediments).

Intellectual Merit:
The workshop will advance the science of Holocene paleoclimatology by fostering paleoclimate studies using peatland archives and integrating them with other high-resolution archives. Workshop products will include summary articles, research collaborations, and spinoff proposals to scientific agencies in North America (including NSF), Europe, and elsewhere.

Broader Impacts:
The workshop will foster international scientific cooperation and collaboration in paleoclimatology. At least 25% of the participants will be from outside North America and western Europe (Asia, South America, former Soviet Bloc), and at least 15% of the participants will be early-career scientists, primarily graduate students and post-docs.

Many species are predicted to shift their ranges over the coming decades in response to changing climate. While much is understood about the climatic controls on species' ranges, little is known about the temporal, ecological, or genetic factors that influence range shifts. This project will examine the expansion of ponderosa pine into the Bighorn Basin of north-central Wyoming to gain an understanding of these factors. This study combines tree-ring analysis and molecular genetic tools to assess species migration and establishment and reveal the patterns of population growth over the landscape over a roughly 500 year time span. Project data will be used to evaluate the ecological and genetic factors that influence colonization, range expansion, and long-term viability of populations at their range margins.

The results of this project provide information on how climate change may influence plant migrations and how these migrations in turn may alter ecosystem structure and function at local to regional scales. This project will foster dialogue between the natural resource management and academic communities through organization of a workshop to communicate findings. A high school student will gain research experience and interdisciplinary training through participation in the project.

Species extinction is a poorly understood process, particularly at local scales, because there are few ecological data sets that span long enough time periods to reveal patterns of extinction. There is perhaps no single place on Earth where changes in the local assemblage of species have been carefully observed and documented continuously at a decadal time scale over several centuries. As a consequence, many basic questions about patterns and rates of species extinction following environmental change are difficult to answer. For example, how many species have been lost from local areas? Do extinctions follow immediately after a disturbance, or are post-disturbance extinctions delayed, resulting in an 'extinction debt' to be paid in the future? Data collected by this project will begin to fill a deficit that has limited scientists' ability to answer these basic questions. Paleontological techniques that have traditionally been used to study changes in plant communities over many thousands of years will be used to examine changes in plant communities in the past few hundred years. Seeds, leaf fragments, and pollen will be analyzed in sediment cores from disturbed wetlands in the Indiana Dunes to create a long-term ecological data set with approximately ten-year intervals from the present day to about 300 years ago. Analysis of these long-term data will advance ecological theory and aid conservation practice by supplying information critically needed to gauge what current patterns of ecosystem change mean for the future.

This project will provide training and mentorship for several undergraduate students, a high school student, a high school teacher, a technician, and a postdoctoral researcher. The project will also support the development of educational and outreach material for K-12 programs.

This project tests a Dynamic Global Vegetation Model (DGVM) using reconstructions of past vegetation for North America and Europe based on paleoecological data. The DGVM is driven by past climate simulated with a fully coupled General Circulation Model (GCM), and the paleovegetation reconstructions are taken from continental scale databases of pollen and plant macrofossil data covering North America and Europe. Past vegetation can also serve as a direct proxy of past climate variations, and recent studies have shown that a DGVM can be used to help interpret the climate signal from pollen and macrofossil data. These techniques allow assessment of the role of non-climatic factors (e.g., CO2) in driving vegetation change. The project is able to identify and reduce bias in climate reconstructions for glacial periods, where these factors are significantly different from the present day.

DGVMs are one of the primary tools used to understand how terrestrial ecosystems might be affected by future climate change under various scenarios. By studying past periods, the predictive ability of these models in simulating ecosystem change under conditions that are different from the present day can be tested. The results from the model runs can also be used to investigate past changes in services provided by terrestrial ecosystems, including carbon sequestration and water resources. The work will also provide an assessment of the GCM used to simulate past climates, which will help to understand its skill in simulating future global change. The project results will include a consistent dataset of environmental conditions covering the last 21000 years. This will be made publicly available at the end of the project, and will provide a context for archeological studies and studies of land-surface history and processes. These results will be transformed into publicly accessible online teaching resources.

Because of the slow pace of terrestrial ecosystem processes, including the slow generation time, growth rate, and decomposition rate of trees, the impact of changing climate and disturbance on forests plays out over hundreds of years. For this reason, centennial scale projections of terrestrial ecosystem models are used to anticipate the trajectory of forest response to environmental change. Modelers would like to have data on how forests have changed at regional scales and over hundreds of years to help assess such projections. A rich assemblage of relevant paleoecological data has been collected, but they have not been synthesized into a form that can be incorporated into broad-scale modeling efforts. Funding provided will support the establishment of a paleoecological observatory network (PALEON) to address this challenge. PALEON is an interdisciplinary team of paleoecologists, environmental statisticians, and ecosystem modelers with the goals of producing rigorous and robust reconstructions of forest change from the Atlantic to the Great Plains over the past 2,000 years, and then using these reconstructions to validate and improve the predictions of terrestrial ecosystem models.

PALEON has identified the integrated analysis of paleoecological data with statistical and mechanistic modeling as a key challenge for improving research capacity for anticipating the future of environmental change. For this reason, PALEON incorporates interdisciplinary training and community building into all aspects of the PALEON mission. In addition to focused working groups, PALEON works with relevant disciplinary communities to develop common approaches to data collection, analysis, and experimental protocols to ensure that long-term data can be seamlessly integrated into macroscale ecosystem analyses. Interdisciplinary training of post-doctoral fellows and graduate students, including a summer short course, will ensure that the next generation of researchers thinks naturally at the spatial and temporal scales relevant to understanding the broad scale impact of changing climate and land-use disturbance.