1. Overwintering Habitat of the
Danaus plexippus L. (Monarch
Butterfly

2. Monarch Butterfly
• Herbivore
• Overwinters in cool,
moist forests
• Found along the coast
of California and in the
state of Michoacán,
Mexico
• Preferred trees are the
Oyamel Pine in Mexico
and the Monterey Pine,
Monterey Cypress and
Blue Gum trees in
California

3. Sources of Information
• Habitat characteristic data from:
• Brower, Lincoln. “Monarch Butterfly Orientation: Missing Pieces of a Magnificent Puzzle”. The Journal of
Experimental Biology 1996: 93-103.
• Brower, Lincoln, Williams, Ernest, Slayback, Daniel, Fink, Linda, Ramirez, Isabel, Zubieta, Raul, Garcia, M.
Ivan, Gier, Paul, Lear, Jennifer and Van Hook, Tonya. “Oyamel fir forest trunks provide thermal advantages for
overwintering monarch butterflies in Mexico”. The Royal Entomological Society 2009: 163-175.
• Tuskes, P.M., Brower, L.P., “Overwintering ecology of the monarch butterfly, Danaus plexippus L., in California”.
Ecological Entomology 1978: 141-153
• Weiss, Stuart, Rich, Paul, Murphy, Dennis, Calvert, William, Ehrlich, Paul. “Forest Canopy Structure at
Overwintering Monarch Butterfly Sites: Measurements with Hemispherical Photography” Conservation Biology
1991: 165-175.
• Clavert, William and Brower, Lincoln. “The location of Monarch Butterfly (Danaus plexippus L.) overwintering
colonies in Mexico in relation to topography and climate”. Journal of the Lepidopterists’ Society 1986: 164-187.
• Spatial and attribute data for California from:
• http://data.geocomm.com
• www.prism.oregonstate.edu
• Spatial and attribute data for Mexico from:
• Dr. Kyle E. Murray
• http://forest.moscowfsl.wsu.edu/climate/current

4. Suitable Factors
• Vegetation: Evergreen Forest
• Minimum Temperatures: 3°C
• Maximum Temperatures: 22°C
• Precipitation: 64cm to 162 cm
• Elevation: 2400m to 3500m in Mexico
• Elevation: 0m to 300m (0ft – 1000ft) in
California

5. GIS Data Processing-California
• Added datasets to ArcCatalog
• Processed vector datasets through the ArcCatalog Toolbox-Import from Interchange
• Unzipped raster datasets and processed through the Tool-ASCII to Raster
• Defined projection on raster data sets to GCS_North America_1983, to match vector
data sets
• Raster maps for precipitation, maximum temperature and minimum temperatures were
clipped
• Built attribute tables for raster datasets
• Increased unique values allowed to include highest number of unique values
• Added new field to minimum and maximum temperatures and precipitation attribute
tables
• Recalculated temperatures in new fields to Celsius and precipitation to centimeters
• Converted elevation and vegetation vector data to raster data
• Reclassified all data to show suitable and unsuitable habitat
• Used the weighted overlay tool to bring all information together into one dataset
• Created various maps

6. California Minimum and Maximum
Temperatures

7. California Annual Precipitation

8. California Land Usage and Elevation

9. GIS Data Processing-Mexico
• Added datasets to ArcCatalog
• Unzipped raster datasets and processed through the Tool-ASCII to
Raster
• Defined projection on raster data sets to GCS_North
America_1927, to match vector data sets
• Raster maps for precipitation, maximum temperature and minimum
temperatures were clipped
• Converted elevation and vegetation vector data to raster data
• Reclassified all data to show suitable and unsuitable habitat
• Used the weighted overlay tool to bring together the elevation and
vegetation information
• Used the weighted overlay tool to bring together the maximum and
minimum temperatures and precipitation
• Created various maps

10. Mexico Minimum and Maximum
Temperatures

11. Mexico Annual Precipitation

12. Mexico Vegetation and Elevation

13. Results
• Large areas appear to be suitable overwintering
habitats for the Monarch Butterfly
• Monarch Butterflies are found in just a few small areas
• Monarchs prefer the older trees for added warmth
• Forest type, temperature and precipitation seemed to
be the most important factors
• Elevation was not consistent between California and
Mexico habitat sites
• Urbanization and deforestation are destroying their
overwintering habitats

14. Results-California

15. Results-Mexico