Met with Stephen Pacala last week, who suggested we look into records of pollen sediments in lakes (varves) as potential data sources for early warning signals. Some potential sources:
- A paper reviewing regime shifts in the pollen records:
- Drying period in N. American midwest look promising
- Williams, J. W., J. L. Blois, and B. N. Shuman. 2011. Extrinsic and intrinsic forcing of abrupt ecological change: case studies from the late Quaternary. Journal of Ecology 99:664-677. doi: 10.1111/j.1365-2745.2011.01810.x
- Paper outlining dataset for N. American vegetation based on varve records:
- Williams, J. W., B. N. Shuman, T. Webb III, P. J. Bartlein, and P. L. Leduc. 2004. Late-Quaternary vegetation dynamics in North America: scaling from taxa to biomes. Ecological Monographs 74:309–334. Eco Soc America. doi: 10.1890/02-4045.
- Data is here, but this is the spatially interpolated set. The original varve data might be more useful.
Started a Mendeley group for this topic.