Part 6—Compare Biodiversity of Regional Forest Plots and Consider Environmental Conditions

Step 1 – Analyze Forest Data From Nokomis, Maine

  1. If necessary, launch My World and open the Maine forest project file from part 5.
  2. If you had trouble making the selections or saving the project file, then use this completed (and saved) project file. Maine_Forest_Part_5.m3vz ( 17.6MB Jun30 10). Right-click or control-click (Mac) the link above to download the file.

  3. Turn on the Nokomis_FIG layer.
  4. Make it the Active layer and click the Zoom to the Active Layerzoom to active layer button.
    1. The Nokomis_FIG layer is on and active in this picture.
      1 Nokomis on Active
    2. After clicking the Zoom to Active Layer button, the Nokomis_FIG layer will be centered in the map window.
      1.5 Nokomis Centered

  5. Now zoom out to see both data sets.
    2 Nokomis and Auburn
  6. Generate a histogram for the Nokomis data layer. Set the View Histogram/Bar Chart for Field to "Species."
  7. Identify the two most abundant tree species. What are the relative percentages of the most abundant species?
    Paper Birch and Northern White Cedar are the two most abundant species. The total number of trees in the Nokomis data file is 134. There are 28 Paper Birch trees, which is 20.8% of the total; there are 22 Northern White Cedar, which is 16.4% of the total.
    3 Nokomis histogram

Step 2 – Compare Nokomis Forest Data to Auburn Data

Question: How do the two woods compare?

  1. Turn on the Auburn_FIG layer.
  2. Zoom to where you can see both layers and turn off the larger group of points, Auburn_FIA2.csv.
  3. Compare the Nokomis_FIG histogram to the Auburn_FIG histogram.
  4. Describe any differences in tree types between each site.
    There are several differences between the plot at Auburn and the plot at Nokomis. The predominant species at Auburn are the Red Maple and Red Oak, while the predominant species at Nokomis are the Northern White Cedar and the Paper Birch. Additionally, the diversity of tree species is greater at Nokomis. Notice also, that while some tree species are the same at both sites, there are a number of tree species found at one site, but not the other. (Click on the image for a larger view.)
    4 both histograms

Step 3 – Add Layers and Consider Environmental Factors That Can Influence Biodiversity

Many environmental factors contribute to, or inhibit, the success of different tree species. Several of these factors include elevation, climate (i.e, temperature and precipitation), drainage, recent fires, soil type, and the presence of invasive species.

  1. Leave both the Nokomis FIG and Auburn FIG layers on the map. Use the Zoom and Move Map tools to zoom out to the State of Maine level.
  2. Explore other layers to discover possible explanations for the differences in the diversity of these two forest plots.
  3. Click the Construct tab and locate the 30-yr average Precipitation and 30-yr Average Surface Temperature layers in the Climatology Data Library.
  4. Add both of these layers to the map. Use the pointer tool to click on the sites where the forest plots are located. Record the 30-yr Average Temperature and the 30-yr Average Surface Temperature for each of the two tree plot areas. Do you see any notable differences?
    1. Click the Construct tab to switch to construct mode.
    2. From the Data Library menu choose Climatology.
      6 climatology data library selected
    3. Click and drag to bring the 30-yr Average Precipitation and 30-yr Average Surface Temperature layers on to the map. Place them under the Biophysical Polygons layer in the Layer List.
      7 add 30 year precip


  5. When these layers are added the map will automatically zoom to the full world view.
    7.5 #0 year temperature added
  6. Zoom and Pan to adjust the map to the region of interest.
  7. Click the Visualize tab to return to visualize mode.
  8. The map now displays the 30-yr Average Precipitation and 30-yr Average Surface Temperature layers and is zoomed in to Maine.
    8 map with both T and P

    These environmental factors such as temperature, precipitation, and elevation may affect the growing season and availability of nutrients. Elevation can affect the drainage and water-retention of a locality.

  9. Turn on the Elevation & Bathymetry layer.
  10. Turn on and off, and otherwise adjust the layers included in the project file to investigate the conditions that might influence biodiversity.
  11. Last, consider other questions that this data might propose: what other variables would you like to investigate and the use of biodiversity as an indicator of forest health.
  12. If you had trouble making the selections or saving the project file, then use this completed (and saved) project file. Maine_Forest_complete.m3vz ( 19.3MB Jun30 10). Right-click or control-click (Mac) the link above to download the file.


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