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Evolution of Grasses and Grassland Ecosystems
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The evolution and subsequent ecological expansion of grasses (Poaceae) since the Late Cretaceous have resulted in the establishment of one of Earth’s dominant biomes, the temperate and tropical grasslands, at the expense of forests. In the past decades, several new approaches have been applied to the fossil record of grasses to elucidate the patterns and processes of this ecosystem transformation. The data indicate that the development of grassland ecosystems on most continents was a multistage process involving the Pale- ogene appearance of (C3 and C4) open-habitat grasses, the mid-late Cenozoic spread of C3 grass-dominated habitats, and, finally, the Late Neogene expansion of C4 grasses at tropical-subtropical latitudes. The evolution of herbivores adapted to grasslands did not necessarily coincide with the spread of open-habitat grasses. In addition, the timing of these evolutionary and ecological events varied between regions. Consequently, region-by-region investigations using both direct (plant fossils) and indirect (e.g., stable carbon isotopes, faunas) evidence are required for a full understanding of the tempo and mode of grass and grassland evolution.
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Climate Science Documents
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Afforestation Effects on Soil Carbon Storage in the United States: A Synthesis
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Afforestation (tree establishment on nonforested land) is a management option for increasing terrestrial C sequestration and mitigating rising atmo- spheric carbon dioxide because, compared to nonforested land uses, afforestation increases C storage in aboveground pools. However, because terrestrial ecosystems typically store most of their C in soils, afforestation impacts on soil organic carbon (SOC) storage are critical components of eco- system C budgets. We applied synthesis methods to identify the magnitude and drivers of afforestation impacts on SOC, and the temporal and verti- cal distributions of SOC change during afforestation in the United States. Meta-analysis of 39 papers from 1957 to 2010 indicated that previous land use drives afforestation impacts on SOC in mineral soils (overall average = +21%), but mined and other industrial lands (+173%) and wildlands (+31%) were the only groups that specifically showed categorically significant increases. Temporal patterns of SOC increase were statistically significant on former industrial and agricultural lands (assessed by continuous meta- analysis), and suggested that meaningful SOC increases require ≥15 and 30 yr of afforestation, respectively. Meta-analysis of 13C data demonstrated the greatest SOC changes occur at the surface soil of the profile, although par- tial replacement of C stocks derived from previous land uses was frequently detectable below 1 m. A geospatial analysis of 409 profiles from the National Soil Carbon Network database supported 13C meta-analysis results, indicating that transition from cultivation to forest increased A horizon SOC by 32%. In sum, our findings demonstrate that afforestation has significant, positive effects on SOC sequestration in the United States, although these effects require decades to manifest and primarily occur in the uppermost (and per- haps most vulnerable) portion of the mineral soil profile.
Abbreviations: BD, bulk density; CI, confidence interval; MAP, mean annual precipitation; MAT, mean annual temperature; SOC, soil organic carbon.
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Agenda - March 11, 2015 Workshop
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Urban Woodlands Conservation and Management Workshop. Organized and facilitated by the National Park Service to identify and create opportunities for greater collaboration among urban woodland researchers and managers working to restore and manage urban woodland ecosystems.
To view the goals and objectives of the workshop, please open the workshop agenda.
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Cultural Resources
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Urban Conservation
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Urban Woodlands Conservation and Restoration
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100 Case Studies Published Today Show How Communities Are Preparing Our Roads, Airports, and Transit Systems for Climate Change
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One hundred case studies released today by the Georgetown Climate Center demonstrate how leaders are responding to the growing threats from climate change to America's roads, airports, transit systems, and infrastructure.
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News & Events
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Secretary Jewell Announces New Wildlife and Climate Studies at the Northeast Climate Science Center
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Secretary of the Interior Sally Jewell announced recently that Interior’s Northeast Climate Science Center (NE CSC) is awarding nearly $700,000 to universities and other partners for research to guide managers of parks, refuges and other cultural and natural resources in planning how to help species and ecosystems adapt to climate change.
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Acquiring Information on the Climate Vulnerability of Appalachian Species and Habitats
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A new report out of the Climate Change Vulnerability Assessment research project addresses how the Cooperative should acquire information about the climate vulnerability of Appalachian species and habitats and share with its partners.
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GOT TREES? Building Climate-Ready Agriculture.
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Agricultural lands are having to meet ever-increasing production and conservation targets. At the same time agriculture’s capacity to deliver these services is being challenged by shifting climate, changing markets, and evolving environmental conditions.
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Enhancing the Climate Resilience of America’s Natural Resources
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The President's Climate and Natural Resources Priority Agenda is the result of an interagency process to inventory and assess current policies, programs, and regulations related to climate change adaptation. The Agenda builds upon the robust climate change adaptation work already accomplished by Federal agencies and identifies significant actions moving forward. It specifically mentions how Federal agencies working to address ecosystem management issues through LCCs and other multi-stakeholder bodies will work with partners to select flagship geographic regions for which they will identify priority areas for conservation, restoration, or other investments to build resilience in vulnerable regions, enhance carbon storage capacity, and support management needs. Within 24 months, these agencies and their partners will have identified and mapped the initial list of priority areas within each of the selected geographic landscapes or regions.
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Building community resilience by strengthening America’s natural resources and supporting green infrastructure
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President Obama has made it clear that we have a moral obligation to our children and future generations to leave behind a planet that is not polluted and damaged. That is why, as part of his effort to combat climate change, the President launched a Climate Action Plan last year to cut carbon pollution, prepare communities for the impacts of climate change, and lead international efforts to address this global challenge.
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Regional Science Efforts Highlighted in National Climate Adaptation Strategy Progress Report
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Report includes several projects in the northeast and the Chesapeake Bay among 50 nationwide examples that illustrate a long-term vision for adaptive management in the face of climate change.
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