John Warren Williams - US grants

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.

Floral and Faunal Community Responses to Late-Quaternary Climate Change

John Williams, Stephen Jackson, Eric Grimm and Russell Graham


The PIs propose a study of the responses of species and communities to
late- Quaternary environmental variations and, in particular, the environmental drivers of species turnover, community assembly and disassembly, and the formation of no-analog communities. Their research will demonstrate the power of NEOTOMA, a new community paleoecological database that reduces informatics costs and removes barriers to interdisciplinary collaboration by storing in a single database most of the major late-Neogene paleoecological databases. The proposed research will be the first-ever synoptic analyses of late-Quaternary community dynamics in North America that directly integrate fossil pollen, plant-macrofossil, and faunal records. The PIs propose improving the resolution of the NEOTOMA database by obtaining 100 new AMS radiocarbon dates for key vertebrate fossil localities, adding recent high-quality records to NEOTOMA, revising existing chronologies in NEOTOMA in light of this new data, and mapping all data for 15 time-windows covering the last 21,000 years. These time windows are more finely subdivided than the original FAUNMAP synthesis, and will permit study of species responses to the rapid climate changes of the last deglaciation. The PIs will test such hypotheses by comparing the distributions of the floral and faunal no-analog communities to each other and to the distributions of no-analog climates. They will create plant based and animal based biome maps to see whether such maps are complementary or in contradiction. The PIs will further conduct generalized dissimilarity modeling to reveal patterns of species turnover, along environmental gradients, in both space and time.

This project will help support the continued development of the field of biogeography, an interdisciplinary study that integrates topics of importance in evolutionary biology, paleo-biology, conservation biology, and ecology. It will accomplish this through funding the travel costs of 40 US graduate students and post-docs to attend the annual meeting of the International Biogeography Society (IBS) in Merida, Mexico, in January 2009. The conference is organized to provide young scientists with networking and educational opportunities that will provide many benefits of broader impact to their professional development, as well as their intellectual development. The IBS meeting emphasizes interaction among scientists from diverse countries, institutions, and career stages, and is designed to highlight and explore the frontiers of the field, fostering the intellectual development of scientists and progress of the field. Additionally, this project significantly enhances international contacts between U.S. graduate students, foreign students, and other scientists of all career stages.

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.

This project will provide new data on the paleoclimates, paleoenviroments and the biodiversity impacts of sea level rise on the southern edge of the Bering Land Bridge (BLB), and is intended to facilitate a better understanding of why woolly mammoths survived late into the mid-Holocene only in the environments of Arctic islands of this area. Furthermore, this research will attempt to establish the actual time of extinction of the Holocene mammoth population on St. Paul Island, Pribilof Islands, Alaska, and apply this information to test various proposed causal hypotheses for the extinction.

Cores from Cagaloq Lake, St. Paul, will be sampled for chironomids (aquatic invertebrates), pollen, coprophilous fungi spores, plant macrofossils, charcoal, ancient DNA and cryptotephras. Oxygen isotopes from the heads of chironomids will provide an independent climate record that can be supplemented by paleoecological analyses of the chironomid assemblages. Studies will also test chironomid species for isotope fractionation to disentangle climate signals from ground water effects. Terrestrial community changes will be reconstructed from pollen, spores and plant macrofossils; and charcoal frequency will be used to document fire events. Analysis of ancient DNA will provide data on cryptic plant and animal species that have not been detected by traditional methods of analysis, and can also be used to identify taxa to species.

Spores that grow on animal dung will be used as proxies for the mammoth population size and to document the time of mammoth extinction on the island. Ancient DNA will serve as an important cross-check by helping to resolve specific identifications of these spores as well as providing an independent estimate the time of extinction by the absence of mammoth DNA.

Digital elevations, bathymetric data, sea level curves, and Geographic Information System (GIS) technology will be used to reconstruct island size from the time of its isolation until today. A highly constrained chronology of the Cagaloq record will be achieved by using 14 C dates and tephras. All data can be compared temporally in order to test hypotheses for mammoth extinction.

This project will provide opportunities for two PhD students, a postdoctoral fellow, graduate student assistant and undergraduate student. Results of the study will be disseminated widely in peer-reviewed journals. An exhibit on the results of the project will be prepared by the EMS Museum at Penn State University with a web component. In addition, a special on-line, interactive exhibit will allow participants to reconstruct the island at various sizes, populate it with differing mammoth populations and define different climate and environmental factors to observe how each of these components affects mammoth extinction. The interactive exhibit will be available on the Neotoma database. Members of the group will make presentations on the project at the Alaska Quaternary Center in Fairbanks, which serves as a hub for promoting Alaska Quaternary research and outreach to the public.

How biological communities respond to environmental change is determined both by the tolerances of individual species and by interactions among species, such as competition, predation, and mutualism. However, little progress has been made in understanding how biotic interactions influence species distributions or in incorporating their effects into models of species assemblages at regional to continental scales. This project will develop and test new methods that consider species interactions by accounting for patterns of species co-occurrence to predict how species and biological communities respond to changes in climate. Observed changes in the distributions of plants and mammals in eastern North America during the last 21,000 years will be combined with independent simulations of past climates to examine how the strength and direction of species interactions vary across broad regions and in response to changes in climate. These data and analyses will also be used to test whether ecological models that consider species co-occurrences have a better predictive ability than existing approaches that model species individually and to identify possible limits to our ability to predict how biological communities may respond to future changes in climate. Results will help address the grand challenge of understanding how changes in climate alter natural systems and their associated ecosystem services.

Beyond providing important insights into how species interactions influence the response of biological communities to changes in climate and our ability to predict these responses, this project will also provide cross-disciplinary training of undergraduate and graduate students and early-career scientists in global change ecology, paleoecology, and statistical modeling. Minority and first-generation undergraduate students will be recruited through campus programs at Frostburg State University and the University of California-Merced. Public outreach to rural communities will be conducted through public lectures and engagements at open house events in an underserved region. In support of open, reproducible science, all publications, datasets, and computer code will be made publicly available.

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, terrestrial ecosystem models are used to anticipate the centennial scale projections of forest response to environmental change. Current terrestrial ecosystem model predictions vary widely and results have large statistical uncertainties. Furthermore, testing and calibration of these models relies on short term (sub-daily to decadal) data that fail to capture longer term trends and infrequent extreme events. The capacity of ecosystem models for scientific inference and long-term prediction would be greatly improved if uncertainties can be reduced through rigorous testing against observational data. PalEON is an interdisciplinary team of paleoecologists, statisticians, and modelers that have partnered to rigorously synthesize longer term paleoecological data and incorporate into ecosystem models to provide a deeper understanding of past dynamics and to use this knowledge to improve long-term forecasting capabilities.

Funds are provided to address four objectives and associated research questions: 1) Validation: How well do ecosystem models simulate decadal-to-centennial dynamics when confronted with past climate change, and what limits model accuracy? 2) Initialization: How sensitive are ecosystem models to initialization state and equilibrium assumptions? Do data-constrained simulations of centennial-scale dynamics improve 20thcentury simulations? 3) Inference: Was the terrestrial biosphere a carbon sink or source during the Little Ice Age and Medieval Climate Anomaly? and 4) Improvement: How can parameters and processes responsible for data-model divergences be improved? The data synthesis will include wide range of ecosystems, encompasses past climate variations that were large enough to affect tree growth rates, disturbance regimes, and forest demography, and leverages available paleodata. The synthesis will include 1) fossil pollen and Public Land Survey data to reconstruct forest composition, 2) sedimentary charcoal, stand-age and firescar indicators of past disturbance regimes, 3) tree-ring records of tree growth rates, and 4) multiple paleoclimatic proxies and paleoclimatic simulations. Bayesian hierarchical statistical models will be used to reconstruct key ecological variables and their associated uncertainty estimates. A standardized model intercomparison involving 13 ecosystem modeling groups will be used to evaluate the robustness of the modeling approach.

Three areas will be emphasized for PalEON's broader impacts. Community Building: The PalEON research community has doubled over the past 10 months, with more than 60 participants now. It is anticipated to nearly another doubling over the next five years, and the funds will allow the ongoing community-building via annual large meetings and task-oriented workshops. Interdisciplinary Training and Mentoring: A new generation of researchers will be trained to naturally conceptualize large spatial and temporal scales and to approach ecological forecasting as an integrative activity spanning data collection to model prediction. Eight postdocs and seven graduate students will be involved in proposed PalEON research, with multiple opportunities for cross-training. Additionally, the PalEON Summer Short Course provides an intensive cross-training experience for young scientists in all areas encompassed by PalEON. The 2012 course will be followed by courses in 2014 and 2016. Building Scientific Infrastructure: All PalEON datasets will be made publicly available upon publication, as will our new data-assimilation methods and model intercomparison protocols. Tools will be developed for optimal site selection (given the goal of reducing the integrated prediction uncertainty about past vegetation and climate over space and time) and will distribute a publicly available webtool version that will be linked directly to the Neotoma Paleoecology Database.

This doctoral dissertation research project will investigate the role of climate change and land use in the emergence and decline of the complex agricultural society at Cahokia, the largest prehistoric Native American settlement north of the Rio Grande. Cahokia was located in southwestern Illinois in the Mississippi River valley near present-day St. Louis. Agriculture began to develop in eastern North America around 4,000 years ago, and by 1050 CE, Cahokia had emerged in the central Mississippi River valley with a population of approximately 10,000 inhabitants, monumental earthworks, and an expansive trade network. Despite its role as a cultural and political center, Cahokia was almost completely abandoned by 1350 CE for reasons that remain unclear. One hypothesis is that prolonged drought or severe flooding caused Cahokia's decline. Other prehistoric agricultural societies appear to have been highly vulnerable to periods of water scarcity that reduced crop yields and triggered social instability. Environmental degradation caused by agricultural intensification may have exacerbated the effects of climatic change and further contributed to Cahokia's decline. To assess the potential role of climate change and resource overexploitation in the emergence and decline of Cahokia, the doctoral student will collect lake sediment cores from four oxbow lakes in in the Mississippi River floodplain along a transect beginning at Cahokia and moving southward towards areas that were less populated during the late prehistoric period. From all sediment cores, the student will develop long-term records of agricultural expansion and contraction (using fossil pollen, charcoal, and carbon isotopes) and hydroclimatic variability (using sediment mineral content and particle-size) that span the last two millennia. These high-quality records of changing land use, land cover, fire regimes, and hydroclimatic conditions that permit tests of hypotheses concerning the role of environmental change in Cahokia's abandonment.

This project will contribute to a broader understanding of the resilience and vulnerability of agricultural societies to land-use intensification and climate variability. By developing an understanding of why past agricultural societies collapsed, this project will provide insights into how to manage contemporary agricultural systems in order to increase their resilience in the face of environmental perturbations. This project lies at the intersection of the earth sciences, ecology, geography, and anthropology, and the researchers will present their work at national conferences to both social and natural scientists. The results of this research will be shared with the public through presentations at the interpretive center at Cahokia. All data will be made publicly available through the Neotoma Paleoecology Database, an online repository for data from lake sediment cores. As a Doctoral Dissertation Research Improvement award, this project will provide support to enable a promising student to establish an independent research career.

Ecologists have long sought to understand how species reshuffle into novel ecological communities during periods of major environmental change, and the consequences of this reshuffling for the services that those ecological communities provide for human society. This project capitalizes on a major historical event - massive changes in plant communities roughly 17,000 years ago - to determine the relative roles that climate change, species interactions, and fire played in the creation of novel communities. Results from this research will inform contemporary debates about the potential for climate change to create 'no analog' communities that differ fundamentally in their structure, function, and the services they provide to society. They will also guide management practices intended to restore communities to prior states and improve our understanding of the consequences of widespread extinctions.

This project builds on prior evidence that plant communities changed dramatically during the last deglaciation because the extinction of large grazers released plants from herbivore suppression. New research will test the novel Megafaunal Release Hypothesis by assessing the relative importance of climate and species interactions on vegetation and fire dynamics. The investigators will collect and analyze a series of lake-sediment cores in the eastern US, and quantify relationships among independent climatic and ecological proxies within and across sites in order to test the Megafaunal Release Hypothesis. Eight new lake sites will be analyzed for indicators of past vegetation composition (fossil pollen), fire regime (sedimentary charcoal), megafaunal abundance (spores from fungi found in dung), and temperature (organic geochemistry). Broader impacts include the mentoring and training of a postdoctoral research scientist, a graduate student, and several undergraduates, and the expansion of collaborations among paleontologists, geographers, and ecologists to understand future environmental change. All data will be made publicly available through standard community data repositories.

Paleontologists provide data about the past distribution and diversity of life. These data are useful both to geologists, because they can help determine the age of rocks, reconstruct past environments, and constrain models of the Earth system; and to biologists interested in the evolutionary history of organisms and the behavior of ecological systems during past global changes. Currently, data about fossils are dispersed across thousands of scientific publications, and dozens of small to large databases, only some of which are publicly available via the Internet. Even publicly available databases can be difficult to access because each stores different kinds of data with different conventions, requiring researchers to individually harmonize searches and their outputs. This project brings together six paleobiological databases so that they share a single set of Internet-based commands by which researchers and the public can easily access fossil records from all of Earth history. By coordinating with other emerging efforts in geological and biological data sharing, best practices, and protocols, we ensure that data will be freely available to all, enabling new scientific syntheses and discovery, more powerful educational opportunities, and general exploration of the history of life on Earth.

The paleobiological sciences sit at the nexus between geosciences and the biosciences, with close interdependencies in both domains. Within the geosciences, information about the past spatiotemporal distribution of organisms, species, and assemblages of species is essential to a wide array of allied disciplines: to sedimentologists and economic geologists studying facies relationships and employing biostratigraphic controls for correlating rock strata, to structural geologists and geophysicists seeking biogeographic constraints on reconstructions of former tectonic plate positions, to paleoclimatologists extracting paleoclimatic signals from paleoecological data, and to earth system modelers seeking to understand how biospheric dynamics have shaped, and continue to shape, the history of the Earth-Life system. Within the biosciences, the fossil record is essential for understanding how contemporary ecological systems are shaped by historical legacies of slow-acting processes, for testing climate-driven models of species distribution and diversity that are being used to project the impacts of 21st century climate change, for constraining phylogenetic models of species divergence and rates of evolution, and for understanding the fundamental drivers of biodiversity (i.e. species extinctions and originations). In an era of global change, when stewarding biodiversity is an urgent societal concern, conservation biologists, global change ecologists, and earth system scientists are all looking to the past to study the behavior of the Earth-Life system during rapid transitions. Paleobiological data are currently served by a wide array of databases that vary in structure, composition, temporal scales, types of data and metadata. To conduct ?global? or holistic analyses of the paleobiological record it is necessary to retrieve data from a variety of these databases - requiring queries of each database to retrieve the types of data needed. The purpose of this project is to make six different paleobiological databases interoperable so that they can be accessed via a common Application Programming Interface (API) to query the data from these and other databases. Towards that end, five key records of North American Pleistocene lakes will be uploaded and become available through this integrative project. This project also will increase the interoperability between these paleobiological resources and contemporary databases of species distributions and diversity, enabling continuous time-series analyses (e.g., of biodiversity) from the beginning of life on earth to today. Integration of the paleobiological databases with databases of the stratigraphic record (Macrostrat) will enhance the value of both types of data. New R packages will facilitate retrieval and analysis of data from all of the databases. Finally, this proposal establishes a Paleobiological Data Consortium, consisting of leaders of cyberinfrastructure resources in the paleobiosciences and allied disciplines, with the goal of sharing best practices and protocols among the geoinformatic and bioinformatic communities.

This Division of Earth Sciences Geoinformatics collaborative award supports continued development of Neotoma, a web-accessible centralized data clearinghouse for paleoecological data for which initial development support was provided by the EAR Geoinformatics Program (EAR- 0948652). This effort will enhance the current Neotoma platform by: 1) maximizing rates of data ingest through on-going data mobilization campaigns, recruitment and training of new data stewards, and development of facilitation software; 2) expanding the Neotoma data model to facilitate new proxy acquisition and secondary data including organic biomarkers, isotopic data from faunal specimens, and faunal taphonomic information; 3) developing new tools for data visualization and scientific exploration; 4) fostering engagement and growth of the Neotoma research community through support for a series of workshops intended to train data users, data stewards, and teachers, and by development of an on-line blog.

The Neotoma geoinformatics platform will promote integrative studies of the biotic impacts of climate change over the past five million years by allowing greater access to previously collected geoscience data sets of relevance and the tools to support analysis at marginal cost. The project will promote community engagement, support ease of data set ingestion, address PI team succession and promote educational module development. This award directly addresses OMB Memo M-13-13 ?Open Data Policy-Managing Information as an Asset.?

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Data heterogeneity and accessibility are major barriers to scientific progress. Many community curated data repositories (CCDRs) have emerged in the paleogeosciences in response to the needs of their scientific communities, but these CCDRs are not well integrated. This project seeks to transform geoscientific research by breaking down the barriers among the CCDRs that serve geoscientists. All participating resources are closely engaged with their respective disciplinary communities and each is mobilizing data from its communities; the key need is to facilitate data interchange among CCDRs. The work will align several major CCDRs using a system that develops new shared services that rely on common standards, and demonstrates the kinds of new scientific insights that become possible with an integrated geoscientific infrastructure.

This collaborative project will accomplish the following: 1) A survey of existing data structures and standards, their suitability for paleogeoscience CCDRs and alignment with requirements identified by the paleogeosciences research coordination network, and their degree of adoption. This will lead to recommendations for adoption by participating resources (EarthChem, Flyover Country, IODP, LacCore/CSDCO, LinkedEarth, Neotoma) and documentation written for geoscientific audiences. 2) Alignment of participating CCDRs to recommended standards and development of a common API that will allow data exchange among CCDRs and to third-party users. 3) Development of an Annotation Engine, which will provide a credentialed, crowd-sourced system for scientists to flag changes to datasets, to connect datasets post hoc, to add context to legacy data, and to provide link-back notification among CCDRs when linked dataset attributes change. Annotation Engine will be embedded into existing scientific CCDR-based workflows, minimizing disruption to users. 4) Development of GeoNoteBase to enable scientists to generate citeable, reproducible workflows that draw information from across data resources, with workflows made available through keyword searches, with full attribution. This is a pilot effort to begin some of the work Through two pilot scientific projects, THROUGHPUT will test and evaluate these new capabilities and demonstrate kinds of new scientific insights that can be gained through integration.

Our understanding of the past is being revolutionized by the study of ancient DNA recovered from fossils and sediments. Because many species do not preserve well in the fossil record, our knowledge is limited about the past locations of species. Ancient DNA can allow the detection of many species that lived in the past. Therefore, understanding how species migrate or otherwise survive past environmental changes can occur. Ancient DNA can also allow the detection of past losses of genetic diversity, due to species extinctions. However, as a data type, ancient DNA falls in a gap between databases designed to store genetic data and other kinds of databases designed to store fossil data. Because of this gap, researchers cannot easily assemble ancient DNA data to study biodiversity changes at large spatial and temporal scales. This project will support a workshop of leading researchers in ancient DNA, biodiversity databases, and paleontological databases, to build new systems for archiving and sharing ancient DNA data. The workshop will allow more open access to ancient DNA data by both researchers and educators. This access will enable more powerful integrative research approaches and authentic teaching experiences.

Specific workshop goals include: 1) review the current state of the art with respect to ancient DNA data; 2) review the current capabilities of existing cyberinfrastructures in genomics and paleoecology; 3) identify gaps and misalignments among existing resources; 4) establish priorities and initial standards for data and metadata reporting in community resources; and 5) envision the establishment of an informatics infrastructure for sedimentary ancient DNA. The people attending this workshop will maximize interdisciplinary exchange of ideas. The workshop will include early career researchers from groups traditionally underrepresented in science and technology. Ultimately, the workshop will produce guidance and resources for researchers working with ancient DNA.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The geoscience community bridges a variety of research areas which use a wide variety of paleoclimatic, geochemical, paleobiological, and archaeological records. This research coordination network supports groups of investigators to communicate, innovate, coordinate, and standardize research practices, training, and educational activities across disciplinary, organizational, geographic and international boundaries.<br/> <br/>Community curated data resources (CCDRs) in the paleoecological, contemporary ecological, paleoclimatic, and archeological disciplines will be improved through three aims: 1) Improving interoperability and reproducibility by developing guidance for interoperability among long-tail CCDRs and promoting adoption of common metadata standards and FAIR (Findability, Accessibility, Interoperability, and Reusability) data principles, 2) Fostering data curation and stewardship by promoting best practices in data science, curation, and stewardship, particularly for early-career researchers, 3) Supporting equity and improving democratization and access to science by promoting the learning and implementation of CARE (Collective Benefit, Authority to Control, Responsibility, and Ethics) principles in disciplinary data resources. Communities of practice will be developed to further these aims through annual in-person symposia and project activities including workshops, working group meetings, and webinars.<br/><br/>This award by the Office of Advanced Cyberinfrastructure is jointly supported by the Directorate for Geosciences.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.