Conservation risks and benefits of establishing monarch butterfly (Danaus plexippus) breeding habitats close to maize and soybean fields in the north central United States: A landscape‐scale analysis of the impact of foliar insecticide on nonmigratory monarch butterfly populations

Thumbnail Image
Date
2021-01-01
Authors
Krishnan, Niranjana
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Person
Bradbury, Steven
Professor Emeritus
Person
Grant, Tyler
Postdoctoral Research Associate
Research Projects
Organizational Units
Organizational Unit
Natural Resource Ecology and Management
The Department of Natural Resource Ecology and Management is dedicated to the understanding, effective management, and sustainable use of our renewable natural resources through the land-grant missions of teaching, research, and extension.
Organizational Unit
Entomology

The Department of Entomology seeks to teach the study of insects, their life-cycles, and the practicalities in dealing with them, for use in the fields of business, industry, education, and public health. The study of entomology can be applied towards evolution and ecological sciences, and insects’ relationships with other organisms & humans, or towards an agricultural or horticultural focus, focusing more on pest-control and management.

History
The Department of Entomology was founded in 1975 as a result of the division of the Department of Zoology and Entomology.

Related Units

Journal Issue
Is Version Of
Versions
Series
Abstract

Establishing habitat in agricultural landscapes of the north central United States is critical to reversing the decline of North America's eastern monarch butterfly (Danaus plexippus) population. Insecticide use could create population sinks and threaten recovery. Discouraging habitat establishment within a 38‐m zone around crop fields is a suggested risk mitigation measure. In Story County, Iowa, United States, this mitigation would discourage habitat establishment in 84% of roadsides and 38% of noncrop land. It is unclear if the conservation benefits from establishing habitat close to crop fields outweigh suppression of population growth owing to insecticide exposure. Consequently, monarch conservation plans require spatially and temporally explicit landscape‐scale assessments. Using an agent‐based model that incorporates female monarch movement and egg laying, the number and location of eggs laid in Story County were simulated for four habitat scenarios: current condition, maximum new establishment, moderate establishment, and moderate establishment only outside a 38‐m no‐plant zone around crop fields. A demographic model incorporated mortality from natural causes and insecticide exposure to simulate adult monarch production over 10 years. Assuming no insecticide exposure, simulated adult production increased 24.7% and 9.3%, respectively, with maximum and moderate habitat establishment and no planting restrictions. A 3.5% increase was simulated assuming moderate habitat establishment with a 38‐m planting restriction. Impacts on adult production were simulated for six representative insecticides registered for soybean aphid (Aphis glycines) management. Depending on the frequency of insecticide applications over a 10‐year period, simulated production increased 8.2%–9.3%, assuming moderate habitat establishment with no planting restrictions. Results suggest that the benefits of establishing habitat close to crop fields outweigh the adverse effects of insecticide spray drift; that is, metapopulation extirpation is not a concern for monarchs. These findings are only applicable to species that move at spatial scales greater than the scale of potential spray‐drift impacts.

Comments

This article is published as Grant, Tyler J., Niranjana Krishnan, and Steven P. Bradbury. "Conservation risks and benefits of establishing monarch butterfly (Danaus plexippus) breeding habitats close to maize and soybean fields in the north central United States: A landscape-scale analysis of the impact of foliar insecticide on nonmigratory monarch butterfly populations." Integrated environmental assessment and management (2021). doi:10.1002/ieam.4402.

Description
Keywords
Citation
DOI
Copyright
Fri Jan 01 00:00:00 UTC 2021
Collections