#18-132 IPPA


Date Full Report Received


Date Abstract Report Received



Primary Investigator:

The goal of this research was to find cost-effective methods to establish and maintain monarch habitat – milkweeds and native wildflowers – on Iowa swine production confinement sites to support monarch butterfly conservation in Iowa. Results from the project were distributed through high-quality videos, print media, and other communications.

In 2016, twelve grass-dominated sites in four central Iowa counties were prepared for planting monarch butterfly habitat by applying glyphosate twice during the growing season. A diverse, native seed mix was planted in early December of 2016 and changes in plant density, plant diversity, and monarch utilization were monitored during the summer of 2017 and 2018. Data was collected three times each summer (June, July, August), beginning the summer before the habitat sites were planted with the native seed mix.

Survey teams recorded monarch presence (eggs, caterpillars, and adults), blooming plants, and vegetation growth and thickness. Increases in native flowers, native plant species diversity, and native milkweeds were recorded. Data analysis shows an increase in monarch eggs, caterpillars and adult butterflies using the new habitat from 2016 to 2018, as well as more blooms, more plant species, and more monarch activity.

The results show that hog confinement locations can provide suitable areas for monarch habitat conservation. This project appeared on the cover of Iowa Pork Producer magazine (May 2019) and farmers Ben Crawford and Tom Tiernan described what they have learned about monarch habitat in video interviews with ISU Extension (2018-2019), available to view at https://monarch.ent.iastate.edu/video.

Key Findings:
• Transitions from mowed turf to diverse native pollinator habitat require careful attention to site selection and site preparation to ensure successful establishment of native plant species at confinement facilities.
• Annual weeds are very common in the early years of site establishment, but the greatest concern is aggressive perennial or biennial weeds that can outcompete native species. For this reason, it helps to know the site’s history and potential weed problems before converting from non-native, cool-season grasses to prairie pollinator habitat.
• Best practices include multiple applications of glyphosate (spring, summer and fall) prior to a no-till, dormant planting of native seed, ideally mid-Nov to mid-Feb.
• Successful establishment of monarch habitat at the swine production sites resulted in a quantifiable increase in adult and larval monarch and bee utilization.
• With proper site selection and pre-planting preparation and maintenance, high- to medium-quality habitat plots can be established, at a reasonable cost, within a few years of planting.