Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population

@article{Pleasants2013MilkweedLI,
  title={Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population},
  author={John M. Pleasants and Karen S. Oberhauser},
  journal={Insect Conservation and Diversity},
  year={2013},
  volume={6}
}
Abstract.  1. The size of the Mexican overwintering population of monarch butterflies has decreased over the last decade. Approximately half of these butterflies come from the U.S. Midwest where larvae feed on common milkweed. There has been a large decline in milkweed in agricultural fields in the Midwest over the last decade. This loss is coincident with the increased use of glyphosate herbicide in conjunction with increased planting of genetically modified (GM) glyphosate‐tolerant corn… 
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References

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TLDR
It is found that monarchs use milkweed in cornfields throughout their breeding season, and that per plant densities are as high or higher in agricultural habitats as in nonagricultural habitats, suggesting that agricultural practices such as weed control and foliar insecticide use could have large impacts on monarch populations.
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1. We use an individual‐based model describing the life of a monarch butterfly, which utilises milkweeds both aggregated in patches and scattered across the wider landscape as a substrate for laying
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TLDR
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TLDR
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Abstract.  1. The status of the eastern North American monarch butterfly population is a highly sensitive issue, given that winter and breeding habitats are being lost at an alarming rate each year,
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