Data & Visualizations
- North American Surface Sample Dataset
- Modern Plant-Climate Research Dataset for Eastern North American Plant Taxa
- Pollen Viewer
- Climate-Dissimilarity Data from Williams et al. 2007, PNAS
- Woody cover reconstructions from Williams et al. 2009, GPC
- Climate-Analog Mapper
This dataset archives pollen surface samples from North America, along with attributed climatic and vegetational data for each location. A full description of the dataset and its compilation is provided by Whitmore et al. (2005). This data is the foundation for a new atlas of modern pollen-climate and pollen-vegetation relationships (Williams et al., 2006). Additionally, PDFs of maps and climate-vegetation-pollen plots though NOAA here.
Whitmore, J., Gajewski, K., Sawada, M., Williams, J. W., Shuman, B., Bartlein, P. J., Minckley, T., Viau, A. E., Webb, T., III, Anderson, P. M., and Brubaker, L. B. (2005). North American and Greenland modern pollen data for multi-scale paleoecological and paleoclimatic applications. Quaternary Science Reviews 24, 1828-1848.
Williams, J. W., B. Shuman, P. J. Bartlein, J. Whitmore, K. Gajewski, M. Sawada, T. Minckley, S. Shafer, A. E. Viau, T. Webb, III, P. M. Anderson, L. B. Brubaker, C. Whitlock, and O. K. Davis. (2006). An Atlas of Pollen-Vegetation-Climate Relationships for the United States and Canada. American Association of Stratigraphic Palynologists Foundation, Dallas, TX, 293p.
This research dataset was created from the North American Modern Pollen Database (version 1.6.1) (Whitmore et al., 2005) with the purpose of modeling plant-climate relationships for taxa in eastern North America. The dataset contains 2,613 sites in eastern North America and Canada. The majority of sites (70.9%) in the research dataset are lacustrine. Palustrine sites compose 2.2% of the dataset and are concentrated in north-eastern Canada in areas where there is a paucity of lacustrine sites. Moss polsters compose 12.1% of the research dataset, and are most concentrated in south-eastern North America and in parts of northern Canada where lacustrine sites are scarce . We also included sites with unknown depositional environments (14.7%) because it is possible they are lacustrine sites. The dataset contains pollen counts, percentages, environmental variables, and fractional woody cover for each site.
Although the primary purpose for creating this dataset was to model late-glacial pollen-climate relationships in eastern North America, other potential uses of this dataset include vegetation reconstruction at local to subcontinental scales and forward modeling of pollen and vegetation from climate variables. For regional- to subcontinental-scale climate and vegetation reconstructions for eastern North America, the research dataset can be used without further modification. Other uses may require either selecting other sets of samples from the North American Modern Pollen Database or collecting additional information not yet available in the NAMPD (e.g. lake area and local vegetation types).
Gonzales, L.M., Grimm, E.C., Williams, J.W, and Nordheim, E.V. (2009) A modern plant-climate research dataset for modeling eastern North American plant taxa. Grana 48: 1-18. (pre-print)
Pollen Viewer (18MB)
Visualizations (online resource)
Pollen Viewer presents animated maps of pollen distributions in North America since the last glacial maximum, which can be used to study how plant distributions responded to late-Quaternary environmental change. The animations can be viewed at the World Data Center; the data files and java applet can be downloaded here. Pollen Viewer was created by Phil Leduc of Brown University. The data and maps underlying Pollen Viewer are described by Williams et al. (2004).
Williams, J. W., Shuman, B. N., Webb, T., III, Bartlein, P. J., Leduc, P.(2004) Quaternary vegetation dynamics in North America: Scaling from taxa to biomes. Ecological Monographs 74: 309-334. (PDF)
These files contain the climate-dissimilarity results reported in Williams et al. 2007, PNAS
The following runs are stored here: 1) "novel" climates: Dissimilarities between each 21st-century target gridcell and its closest 20th-century analogue. These results are shown in Panels 2C and 2D of Williams et al. 2007. 2) "local" climate change: Dissimilarities calculated between the late 20th-century and late 21st-century climate for each gridcell. These results are shown in Panels 2A and 2B of Williams et al. 2007. 3) "disappearing" climates: Dissimilarities between each 20th-century target gridcell and its closest 21st-century analogue. These results are shown in Panels 2E and 2F of Williams et al. 2007. 4) same as "novel" climates, except that a 500-km constraint was placed on the search for analogues. High SED values indicate novel climates within this search radius. These results are shown in Panels 3A and 3B of Williams et al. 2007. 5) same as "disappearing" climates, except that a 500-km constraint was placed on the search for analogues. High SED values indicate disappearing climates within this search radius. These results are shown in Panels 3C and 3D of Williams et al. 2007.
Williams, J. W., Jackson, S., and Kutzbach, J. (2007). Projected distributions of novel and disappearing climates by 2100 AD. Proceedings of the National Academy of Science 104: 5738-5742. (PDF)
Woody cover reconstructions (782KB)
This dataset archives woody cover reconstructions for Midwestern US pollen records, based on the modern analog technique applied to AVHRR data. Data and methods described in Williams et al. (2009), Global and Planetary Change.
Williams, J.W, Shuman, B., and Bartlein, P.J. (2009) Rapid responses of the prairie-forest ecotone to early Holocene aridity in mid-continental North America. Global and Planetary Change. 66: 195-207
Climate-Analog mapper (online resource)
This website allows you to ask a simple question: What climates today most resemble the future climates projected for my location? An interactive map interface enables users to find contemporary analogs for the future climates projected for Wisconsin locations. Developed as part of the Wisconsin Initiative on Climate Change Impacts (WICCI).
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