Establishing habitats in GM crop landscapes to benefit monarch butterflies, pollinators and ecological services

Abstract: For two decades genetically modified (GM) maize and soybeans have dominated crop fields in Iowa. Among other benefits their use led to reduced insect pressure and initially more efficient weed control. There are concerns that herbicide use associated with herbicide-tolerant crops reduced common milkweed (Asclepias syriaca) in crop fields. Common milkweed is the most important host plant of the monarch butterfly (Danaus plexippus) in the United States (U.S.) Corn Belt. The monarch butterfly is perhaps the most recognizable insect in North America. Their populations have declined dramatically over the past two decades due to multiple factors, including loss of overwintering habitat in Mexico, breeding habitat in the U.S., and milkweed within crop fields. Research has focused on ways to increase biodiversity in agricultural landscapes in Iowa by planting native plants near and sometimes in borders of crop fields. These plantings provide shelter and food for butterflies, pollinators, birds and other organisms. Strategically placed habitat also can be stacked with edge of field practices designed to control erosion and nutrient runoff. The Iowa Monarch Conservation Consortium that includes agricultural, conservation, academic and governmental organizations was formed to improve survival and reproduction success through voluntary action. The goal is to establish native plant habitats throughout Iowa with a focus on areas near agricultural land by working with the more than 30 consortium members and partners. Science-based approaches will be used to develop practical, cost-effective guidelines to help landowners establish habitats in filter strips, bioreactors and grass-dominated land. The premise is that growers do not want milkweeds on productive land but they would consider establishing them and nectar plants on non-crop and non-productive land.