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Assignment 2 – Pollen Diagram Analysis (10% total)
Overview and Due Date
Due Date: November 14th, 2024, 10:00 pm (Toronto/Eastern Time)
Format: Submit your completed pollen diagram and an associated written discussion.
Reminders
• Read the assignment instructions carefully to fully understand what is expected of you.
Make sure to fully respond to all questions in the assignment to receive full marks.

• You are expected to submit your own work supported by relevant and reliable sources.
These sources must be credited using in-text citations and a references list in APA (7th
edition) format. The use of generative AI tools or apps may be permitted within the
limitations stated in the syllabus. Microsoft Copilot is the only acceptable AI application
for this course.

• After the assignment deadline and applicable extensions, a penalty of 5% per day
(including Saturday and Sunday) will be applied for up to one week past the original due
date on late submissions. See the syllabus for full details on late penalties and missed
term work. Extensions will be granted upon request, question-free with documentation
or for 5 “Weekly Challenge” points without.

Introduction
In Assignment 1, we explored how different plants from around the world have adapted to
their current environmental conditions. Yet, environmental conditions are temporally dynamic
which can result in changes in community composition and biome shifts over time (Cox et al.,
2020)
The goal of this assignment is for you to consider how plant communities and biomes have
changed over time following a recent deglaciation event using preserved pollen data.
Based on the course learning outcomes, this assignment provides an opportunity for you to:
• Identify and describe patterns of species distributions and explain how they are
shaped by various physical and ecological controls across spatial and temporal
scales.
• Explain how evolutionary, tectonic, and climatic processes influence the
distribution of species over geologic time.
GGR305 Biogeography
Fall 2024
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• Discuss modern species distributions in the context of biogeographical processes
and human activities.
• Apply quantitative and spatial reasoning through analysis and interpretation of
data, graphs, and maps.
• Synthesize reliable literature related to biogeography into written formats aimed at
an appropriate audience.
Background Information
Palynology and Pollen Diagrams
Palynology is the study of microscopic objects of
organic composition – things like pollen and
spores (amongst others) (MacDonald, 1988). An
abundant source of information concerning past
plant taxa stems from the preservation of
unique pollen and spores in various
environments, including lakes, bogs, peat
deposits, and more. Combined with radiocarbon
dating techniques, these preserved pollen and
spores can provide a record of changing local
communities over time (Figure 1) (MacDonald,
1988).
Using our modern understanding of the linkages
between vegetation and climate, we can apply
space-for-time substitution to approximate past
environmental conditions (Figure 2) (Chevalier
et al., 2020).
Figure 1 – Examples of different pollen morphologies and their associated common species names (top). Bottom -
simplified pollen diagram from Nelson Lake, Illinois showing the changes in species-specific pollen abundance over the
last ~17 000 years (Bierman & Montgomery, 2020).
GGR305 Biogeography
Fall 2024
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Figure 2 - Space-for-time substitution principle used in many pollen-based climate reconstructions. At the top of the
diagram, the modern climate, vegetation, and pollen relationships are observed and known. These relationships are
then used to predict past climatic conditions based on the presence of certain observed fossilized pollen (bottom)
(Chevalier et al., 2020).
How to Read a Pollen Diagram
A pollen diagram generally displays pollen data for various plant species side-by-side (Figure 3).
In Figure 3, the x (horizontal) axis shows the abundance (e.g., percent) of each type of pollen
within the sample and the y (vertical) axis shows depth or time increments with the most recent
deposits at the top.

Figure 3 - Example pollen diagram for Nelson Lake, Illinois. The diagram shows how regional plant communities
changed over the last ~17,000 years. Note major changes in pollen types and/or percentages occurred
approximately 14 000, 12 000, 11 000, 2 000, and less than 1000 years ago. (Source: Illinois State Museum, 2000).
GGR305 Biogeography
Fall 2024
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Taxa represented in pollen diagrams may be grouped into representative categories. In Figure 3
it is done by colour – evergreen (blue), deciduous (green), evergreen/deciduous (orange), herbs
(yellow) (Illinois State Museum, 2000).
Obvious changes in pollen types and/or relative abundance are used to divide the pollen record
into ‘pollen zones’ (see the horizontal lines in Figures 1 and 3) (Allaby, 2010). Therefore, each
zone represents a period of time with relatively consistent pollen types and abundances (Allaby,
2010). With knowledge of the general environmental preferences of the taxa associated with
each pollen type, changes in composition may be broadly related to changing environmental or
land management conditions through time (Figure 2).
For example, compared to spruce trees, oak trees are generally found in warmer and wetter
climates (Bierman & Montgomery, 2020). Therefore, we can expect that around 11,000 - 12,000
years ago the conditions around Nelson Lake were becoming warmer and wetter as ash and oak
trees began to establish and the abundance of spruce trees declined (Figure 1 and Figure 3).
Other changes in plant species composition examples are less environmentally driven. For
example, the appearance of ragweed in the last several hundred years is indicative of land
clearing following European settlement (Figure 1 and Figure 3) (Bierman & Montgomery, 2020).
Additional Background Resources
The following resources will provide important information for how to interpret your results. In
addition, the papers by Anderson (1989) and Jacobson et al. (1987) are great examples of how to
discuss pollen data. The following are available through Quercus ‘Library Reading List’ or online.
Anderson, T.W. (1989). Vegetation changes over 12,000 years: changes in eastern Ontario and
adjacent areas give evidence of global change. GEOS (Energy, Mines and Resources
Canada), 18, 39-47.
• Includes a vegetation reconstruction for eastern Ontario/southern Quebec, a site
located to the east of ours. It experienced slightly different patterns of vegetation
change and perhaps unique driving forces; the discussion in this paper will assist in
interpreting your own results.
Burns, R. M. & Honkala, B.H. (1990). Silvics of North America. U.S. Department of Agriculture,
Forest Service. https://www.srs.fs.usda.gov/pubs/misc/ag_654/table_of_contents.htm
• Provides helpful details on the known growth and climate conditions of trees.
Cox, C. B., Ladle, R. J., & Moore, P. D. (2020). Biogeography: An ecological and evolutionary
approach (10th ed.). John Wiley & Sons Ltd.
• Chapter 12, including pollen diagram examples
• Chapter 13, Section: The Environmental Impact of Early Human Cultures
GGR305 Biogeography
Fall 2024
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