Overwintering Habitat of the Danaus plexippus L. (Monarch

Butterfly

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

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

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

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

California Minimum and Maximum Temperatures

California Annual Precipitation

California Land Usage and Elevation

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

Mexico Minimum and Maximum Temperatures

Mexico Annual Precipitation

Mexico Vegetation and Elevation

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

Results-California

Results-Mexico