Long-term Trends in Midwestern Milkweed Numbers and Their Relevance for Monarchs

Declines in Milkweed abundances are assumed responsible for declines in Monarch butterfly numbers. We use data from the most exhaustive Milkweed surveys ever conducted to test whether the Monarch’s host plants are declining, and whether this explains butterfly declines. We also describe what these results mean for land management and land use in the Midwest if Monarchs are to be conserved.