Long-term Trends in Midwestern Milkweeds and their Relevance for Monarchs



This is the dataset used in the BioScience publication of the same name.

More information about this dataset:

Interested parties can request data from the Critical Trends Assessment Program, which was the source for the data on natural areas in this study. More information on the program and data requests can be obtained by visiting the program webpage.
Critical Trends Assessment Program, Illinois Natural History Survey. http://wwx.inhs.illinois.edu/research/ctap/

These spatial datasets were used for analyses:

Illinois Natural History Survey. 2003. Illinois GAP analysis land cover classification 1999-2000, 1:100 000 Scale, Raster Digital Data, Version 2.0. Champaign, IL, USA.
Illinois State Geological Survey. 1995. Illinois Landcover Thematic Map Coverage Map 1991-1995. Champaign, IL, USA.
Illinois State Geological Survey. 2001. Illinois Landcover Thematic Map Coverage Map 1999-2000. Champaign, IL, USA.
USDA National Agricultural Statistics Service Cropland Data Layer. 1999-2015. Published crop-specific data layer [Online]. Available at https://nassgeodata.gmu.edu/CropScape/. USDA-NASS, Washington, DC.

Information on agricultural practices and landcover changes were derived from the following U.S. Department of Agriculture (USDA) resources:

USDA Economic Research Service. 2016. Adoption of Genetically Engineered Crops in the U.S. Available at http://www.ers.usda.gov/data-products/. USDA-ERS, Washington, DC.

USDA Natural Resources Conservation Service. 2015. Summary Report: 2012 National Resources Inventory. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcseprd396218.pdf. USDA-NRCS, Washington, DC, and Center for Survey Statistics and Methodology, Iowa State University, Ames, Iowa.
Date made availableNov 30 2016
PublisherUniversity of Illinois at Urbana-Champaign


  • BioScience
  • Monarch Butterfly
  • CTAP Critical Trends Assessment Program
  • Milkweed

Research Output

Long-term trends in midwestern milkweed abundances and their relevance to monarch butterfly declines

Zaya, D. N., Pearse, I. S. & Spyreas, G., Jan 1 2017, In : BioScience. 67, 4, p. 343-356 14 p.

Research output: Contribution to journalArticle

  • Cite this

    Spyreas, G. R. (Creator), Zaya, D. N. (Creator), Pearse, I. (Creator) (Nov 30 2016). Long-term Trends in Midwestern Milkweeds and their Relevance for Monarchs. University of Illinois at Urbana-Champaign. 10.13012/B2IDB-5072223_V1