ENVS 110 - Analysis of a Pollen Diagram

After analyzing two synthetic pollen diagrams in class, here is the real thing. Mudge Pond is a small pond in north-western Connecticut. We obtained quite a few cores from it in 2003 - 2006, and Jeff Abrams ('05) analyzed the pollen variations as part of his senior thesis. The figure below shows a summary of his results. Shown are the relative pollen abundances of five tree species and ambrosia (ragweed - read more about it here). For a map of Mudge Pond click here.

Note: the abundances shown below are relative abundances. that means if one component increases all the others have to decrease as their sum adds up to a total of 100%. Sediment age increases downwards (as you go down into the hole) and is given in years before present (years B.P.).

To help you with your interpretation use the following links:

distribution maps of selected US tree species
climate of the United States - mean annual precipitation
climate of the United States - mean annual temperature

Assignment:

Based on the variations in tree pollen, what can you say about climatic changes (or the lack thereof) that occurred in western Connecticut over the last 12,000 years.
Ambrosia, a weedy plant that requires ample sunlight has been mostly absent from the pollen record except for the very recent past. Can you imagine any likely causes for this dramatic change?

I expect you to write about half a page (typed, 12 pt. font). Make sure you include your climatic interpretation and tell me how you arrived at your conclusions.

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