19 Mar 2012:
U.S. Monarch Butterfly Decline
May Be Linked to GM Crop Use, Study Says
A new study suggests that the increased use of genetically modified (GM) crops across the Midwestern U.S. may be causing a decline in monarch butterfly populations
. From 1999 to 2010, a period when GM crops
A monarch butterfly
became more common on U.S. farms, the number of monarch eggs in the Midwest declined by 81 percent, according to researchers from the University of Minnesota and Iowa State University. The reason, according to the study, is the near-disappearance of milkweed, an important host plant for monarch eggs and caterpillars. The researchers attribute sharp declines in milkweed to widespread use of genetically modified corn and soybeans that are resistant to the herbicide, Roundup, which is then sprayed on fields, killing milkweed. Other experts say it is too early to link GM crops to population declines, suggesting that other causes, including damage to the butterflies’ wintering grounds in Mexico, may be a factor. In a separate study, U.S. researchers say early snowmelt in the Colorado Rocky Mountains may be causing a decline in populations of the Mormon Fritillary butterfly because the advanced melting is triggering a decline in the insect’s preferred flower species
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Tribal people and ranchers join together to stop a project that would haul coal across their Montana land. Watch the video.
is now available for mobile devices at e360.yale.edu/mobile
An aerial view of why Europe’s per capita carbon emissions are less than 50 percent of those in the U.S. View the photos.
Ugandan scientists monitor the impact of climate change on one of Africa’s most diverse forests and its extraordinary wildlife. Learn more.
video series looks at the staggering amount of food wasted in the U.S. – a problem with major human and environmental costs. Watch the video.
video goes onto the front lines with Colorado firefighters confronting deadly blazes fueled by a hotter, drier climate. Watch the video.
A three-part series Tainted Harvest
looks at the soil pollution crisis in China, the threat it poses to the food supply, and the complexity of any cleanup. Read the series.